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Liberty Basic Manual - Epping Boys High School

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6. mainLoop print graph setfocus input r fetch a character was typed key InkeyS if len key 1 then notice key was pressed else keyValue asc right key 1 if keyValue VK SHIFT then notice Shift was pressed else if keyValue VK CONTROL then notice Ctrl was pressed else notice Unhandled key pressed end if end if end if WAIT Inkey holds multiple key information If Inkey holds more than one character the first character will indicate whether the Shift Ctrl or Alt keys was depressed when the key was pressed These keys have the following ASCII values Shift 4 Ctrl 8 Alt 16 They can be used in any combination If Inkey contains more than one character you can check to see which if any of the three special keys was also pressed by using the bitwise AND operator If shift alone was pressed then the ASCII value of the first character will be 4 If Shift and Alt were both pressed then the ASCII value of the first character will be 20 and so on Special keys trigger a new value for Inkey when they are pressed and again when they are released Here is an example that uses bitwise AND to determine which special keys were pressed open Inkey with Shift for graphics nf nsb as 1 1 setfocus when characterInput check 1 down place 10 30 1 Make the mainwindow visible 1 then click this window and 1 begin pressing key combinations 1 Watch the printout
7. next index DisplayWidth Description The special variable DisplayWidth contains the width of the display screen in pixels DisplayHeight Description The special variable DisplayHeight contains the height of the display screen in pixels DO LOOP do code in here loop while booleanExpr execute the code inside this loop at least once do code in here loop until booleanExpr do while expr some code loop do until expr some code loop Description DO and LOOP cause code to be executed while a certain condition evaluates to true or until a certain condition evaluates to true The while and until parts of this expression can be located either in the DO statement or the LOOP statement The following form is good for cases when you want a loop that always executes once and then only loops back as long as a condition is met It will continue looping back and executing the code as long as the booleanExpr evaluates to true execute the code inside this loop at least once do code in here loop while booleanExpr You can also use the UNTIL keyword to reverse the logic of the expression execute the code inside this loop at least once do code in here loop until booleanExpr Usage examples using loop while and loop until print print a zero do print a a a 1 loop while a gt 10 print print print 1 to 9 do print a a a 1 loop while a lt 10 print examples using l
8. Pick a contact status options 0 Cold Contact Phone Call options 1 Send Literature options 2 Follow Up Call options 3 Send Promotional optionss 4 Final Call listbox status list options selectionMade 5 35 250 90 button status Continue selectionMade UL 5 5 button status Cancel cancelStatusSelection UR 15 5 WindowWidth 270 WindowHeight 180 open Select a contact status for window as status wait selectionMade print status list selection selections notice selection was chosen close status end cancelStatusSelection notice Status selection cancelled close status end Control of the listbox in the sample program above is provided by printing commands to the listbox just as with general window types in Liberty BASIC The listbox has the handle status list so to find out what was selected use the statement print status list selection selection If the result is a string of length zero a null string this means that there is no item selected Subroutine Event Handler Sample program Pick a contact status options 0 Cold Contact Phone Call options 1 Send Literature options 2 Follow Up Call options 3 Send Promotional optionss 4 Final Call listbox status list options selectionMade 5 35 250 90 button status Cancel cancelStatusSelection UR 15 5 WindowWidth 270 Windo
9. input Pleas nter the upper limit limit produces Please enter the upper limit and input limit produces simply H In the simple form input limit the question mark is inserted automatically but if a prompt is specified as in the above example only the contents of the prompt are displayed and nothing more Ifit is necessary to obtain input without a prompt and without a question mark then the following will achieve the desired effect input limit Additionally in most Microsoft BASICs if INPUT expects a numeric value and a non numeric or string value is entered the user will be faced with a comment something like Redo From Start and be expected to reenter Liberty BASIC does not automatically do this but converts the entry to a zero value and sets the variable accordingly The prompt may be expressed as a string variable as well as a literal string promptS Pleas nter the upper limit input promptS limit See also INPUT h n INPUTTO h c Line Input INPUTS h n INPUT handle items Description This permits the retrieval of a specified number of items from an open file or device using handle If handle does not refer to an open file or device then an error will be reported It can also be used to read a character at a time from the mainwindow see example below Usage read and display a file one character at a time open c autoexec bat for input as 1 loop
10. open name for input as pic picS input pic 29 close pic HeightBitmap asc mid pic 23 1 _ asc mid pic 24 1 256 end function sub MakeMask wide high hWnd cursor hourglass white 255 256 256 255 256 4 255 black 0 open user32 for dll as user Open gdi32 for DLL as Zodi CallDll user GetDC hWnd as long hDC as long for i 0 to wide 1 for j 0 to high 1 CallDll Zodi GetPixel hDC as long _ i as long _ j as long _ pColor as long if pColor black then newColor white else newColor black end if CallDll gdi SetPixel hDC as long _ i as long j as long _ newColor as long r as long next j next i CallDll user ReleaseDC hWnd as long hDC as long _ r as long close user close gdi cursor normal end sub Step by Step Here is a step by step review of sprite animation See a Simple Demo Program 1 Open a window containing a graphicbox or open a graphics window 2 Load bitmaps for all sprites with the LOADBMP command Sprite bitmaps can also be created at runtime For an example see the Simple Demo Program 3 Optional Load bitmap for background s with the LOADBMP command OR 4 Optional Load bitmap for background s by drawing desired background onscreen and saving it to memory with the GETBMP command 5 Set the background for animation with the BACKGROUND command 6 Add all sprites with an ADDSPRITE command for each
11. 0 then wait this causes any extra ticks to be x x 5 y y 5 print w g backgroundxy x y print w g drawsprites print w g spritecollides guy lists if listS girl then print w g color black font arial 14 print w g place 140 280 Boy meets girl ms end if wait timerScroll 0 function timerScroll ms timer ms scroll timerScroll ms end function quit close w end ignored Lander bas Here is a more advanced game that uses sprite graphics It is a clone of the arcade game Lunar Lander Lunar Lander Lander bas written by Carl Gundel carlg world std com Needs at least Liberty BASIC v2 0 This file is contributed to the public domain At this stage it is merely a prototype Use the keys 0 through 9 to control thrust Use the and keys to rotate the ship You must make a VERY gentle and level landing on one of the flat areas open game window nomainwin UpperLeftX 50 UpperLeftY 50 WindowWidth 500 WindowHeight 340 dim terrain 500 open Lunar Lander for graphics nsb as lander print lander when characterInput userInput print lander trapclose quit WindowWidth 640 call makeSprites call setBackground print lander spritexy lem 50 50 print lander spritescale lem 200 startGame initialize print lander setfocus fuel 10000 altitude 0 attitude 0 longitude 10 thrust 0
12. 50 Produces hello world MID string index number Description This function permits the extraction of a sequence of characters from string starting at index number is optional If number is not specified then all the characters from index to the end of the string are returned If number is specified then only as many characters as number specifies will be returned starting from index Usage print mid greeting Earth creature 10 5 Produces Earth And stringS The quick brown fox jumped over the lazy dog for i 1 to len stringS step 5 print mid string i 5 next i Produces The_q uick_ brown _fox_ jumpe_ d_ove r_the _lazy _dog LOWER string Description This function returns a copy of the contents of string but with all letters converted to lowercase Usage print lower The Taj Mahal Produces the taj mahal UPPER string Description This function returns a copy of the contents of string but with all letters converted to uppercase Usage print upperS The Taj Mahal Produces THE TAJ MAHAL TRIM string Description This function removes any spaces from the start and end of string This can be useful for cleaning up data entry among other things Usage Ww sentenceS Greetings print len trim sentence Produces 9 SPACE n Description This function will a return a string of n space characters ASCII 32 It is useful when p
13. Cancel Add to Custom Colors SEED ERAN 4 4 Combobox Combobox Combobox First Hem Second Hem Third Item Fourth Wem R Fifth Item Sixth Item Seventh Wem Eighth Item Ninth Item Tenth Item Eleventh Wem Twelfth Hem Thirteenth Item Fourteenth Hem Fifteenth Item Sixteenth Wem COMBOBOX handle ext array eventHandler xPos yPos wide high Description Comboboxes are a lot like listboxes but they are designed to save space Instead of showing an entire list of items they show only the selected one When the user clicks on the checkbox arrow button to the right a list appears drops down It is then possible to browse the possible selections and pick one if so desired When the selection is made the new selection is highlighted The user can type into the textbox part on top of the combobox rather than choosing an item from the dropdown list The program can get the contents of this field The combobox is loaded with a collection of strings from a specified string array and a reload command updates the contents of the combobox from the array when the contents of array change handle ext The handle part of this item needs to be the same as the handle of the window containing the combobox The evt part needs to be unique so that the program can send commands to the combobox and get information from it later array This is the name of the array must be a
14. GOTO label Description GOTO causes Liberty BASIC to proceed to the program code following the label using the form GOTO label The label can be either a traditional line number or a branch label in the format branchLabel where the branch label name can be any upper lowercase letter combination Spaces and digits are not allowed Here are some valid branch labels mainMenu enterLimits repeatHere Here are some invalid branch labels enter limits mainMenu 1moreTime Usage repeat askAgain print Make your selection m r x input selections if selectionS M then goto menu if selection S R then goto repeat if selections X then goto exit goto askAgain menu print Here is the main menu exit print Okay bye end Notes In the lines containing IF THEN GOTO the GOTO is optional The expression IF THEN menu is just as valid as IF THEN GOTO menu But in the line GOTO askAgain the GOTO is required See also GOSUB Graphicbox graphicbox handle ext xOrg yOrg width height Description The graphicbox is a control that can be added to any window type It understands all of the commands of that are used in a window of type graphics handle ext The handle part must be the same as the window that will contain the graphicbox The ext part must be unique for the graphicbox xOrg amp yOrg These specify the position of the graphicbox
15. Some common window and control styles are listed below To find all possible style bits used to create controls in Windows refer to API references online or in books for the functions to CreateWindow and CreateWindowEx handle This must be a handle of handle variable that refers to a control See the code below for a demonstration addBits This contains all style bits that should be added to the control If there are more than one they must be put together with the bitwise OR operator like this ES AUTOVSCROLL or _ES MULTILINE removeBits This removes style bits from the control To remove a border from a control this value would be _WS_BORDER addExtendedBits This adds bits to the extended style Windows created with an extended style have extended style bits like WS EX _CLIENTEDGE removeExtendedBits This removes bits from the extended style Windows created with an extended style have extended style bits like WS EX _TOOLWINDOW Usage here is a textbox with a password setting stylebits main pw E PASSWORD _ES AUTOVSCROLL or ES MULTILINE 0 0 textbox main pw 10 10 250 25 here is one right justified and we use a handle variable justHandle main rjust stylebits justHandle ES RIGHT 0 0 0 textbox main rjust 10 40 250 25 here s a silly example of twiddling style bits for a window stylebits main WS SYSMENU WS POPUP WS EX CONTEXTHELP 0
16. end For information on creating controls with different background colors see Colors and the Graphical User Interface Texteditor extEditor TEXTEDITOR handle ext xpos ypos wide high Description Texteditor is a control similar to textbox but with scroll bars and with an enhanced command set The commands are essentially the same as that of a window of type text NOTICE that texteditor commands start with an exclamation point because the control will simply display anything printed to it if it doesn t start with an exclamation point The texteditor provides a method for the user to create and edit large amounts of text The addition of a texteditor control to a window automatically causes the menubar to contain an EDIT menu Right clicking within a texteditor control pops up an automatic EDIT menu handle ext The handle part must be the same as for the window that contains the texteditor control The ext part must be unique for the texteditor xpos amp ypos This is the position of the texteditor in x and y from the upper left corner of the window wide amp high This is the width and height of the texteditor in pixels Here are the texteditor commands print handle autoresize This works with texteditor controls but not with textbox controls or text windows This causes the edges of the control to maintain their distance from the edges of the overall window If the user resizes the window the texteditor
17. end The prompt may be expressed as a string variable as well as a literal string promptS Pleas nter the upper limit input prompt limit Most versions of Microsoft BASIC implement INPUT to automatically place a question mark on the display in front of the cursor when the user is prompted for information input Pleas nter the upper limit limit produces Please enter the upper limit Liberty BASIC makes the appearance of a question mark optional input Pleas nter the upper limit limit produces Please enter the upper limit and input limit produces simply In the simple form input limit the question mark is inserted automatically but if a prompt is specified as in the above example only the contents of the prompt are displayed and nothing more Ifit is necessary to obtain input without a prompt and without a question mark then the following will achieve the desired effect input limit Additionally in most Microsoft BASICs if INPUT expects a numeric value and a non numeric or string value is entered the user will be faced with a comment something like Redo From Start and be expected to reenter Liberty BASIC does not automatically do this but converts the entry to a zero value and sets the variable accordingly Mainwin Size It is possible to set the number of columns and rows in the mainwindow using the MAINWIN statement Here is how to set 40 columns and 20 rows
18. print handle ext reload This will reload the listbox with the current contents of its array and will update the display print handle ext locate x y width height This repositions the listbox control in its window This only works if the control is placed inside window of type window The control will not update its size and location until a REFRESH command is sent to the window See the RESIZE BAS example program print handle ext font facename pointSize This sets the listbox s font to the specified face and point size If an exact match cannot be found then Liberty BASIC will try to find a close match with size taking precedence over face For more on specifying fonts read How to Specify Fonts Example print handle ext font times new roman 10 print handle ext singleclickselect This tells Liberty BASIC to jump to the control s branch label on a single click instead of the default double click print handle ext setfocus This causes the control to receive the input focus This means that any keypresses will be directed to the control print handle ext enable This causes the control to be enabled print handle ext disable This causes the control to be inactive and grayed out print handle ext show This causes the control to be visible print handle ext hide This causes the control to be hidden or invisible Sample Program Branch Label Event Handler Sample program
19. print hexdec amp HFF See also DECHEXS HWND handle Description This function returns the Windows handle a numeric value for the window referred to by the Liberty BASIC handle This is very useful for making many different kinds of Windows API calls and many third party DLLs will require that this value be provided for their own purposes Usage open Example for window as 1 hl hwnd 1 IF THEN ELSE END IF IF test expression THEN expression s IF test expression THEN expression s 1 ELSE expression s 2 IF test expression THEN expression s 1 END IF IF test expression THEN expression s 1 ELSE expression s 2 END IF Description The IF THEN statement provides a way to change program flow based on a test expression For example the following line directs program execution to branch label soundAlarm if fuel runs low if fuel lt 5 then soundAlarm Another way to control program flow is to use the IF THEN ELSE statement This extended form of IF THEN adds expressiveness and simplifies coding of some logical decision making software Here is an example of its usefulness Consider retry input Please choose mode N ovice or e X pert modes if len mode 0 then print Invalid entry Retry goto retry mode left mode 1 if instr NnXx mode 0 then print Invalid entry Retry goto retry if instr Nn modeS gt 0 then print Novice mode goto
20. 1 so info n 1 0 the complete path of a directory entry ie work math info n 1 1 the name of the directory in specified ie math You can optionally specify a wildcard This lets you get a list of all ini files for example This is how you do it files DefaultDir ini info This also makes it practical to use to check for file existence If you want to know if a file c config bak exists you could try files c config bak infoS If val info 0 0 gt 0 then the fil xists FONTDIALOG Font Font Font style Si arial Italic O Arial Black O Arial Narrow O Arial Rounded MT Bok O Arial Unicode MS O Baskerville Old Face Batang hd Bold Bold Italic Sample AaBbYyZz Script Western This is an OpenType font This same font will be used on both your printer and your screen FONTDIALOG fontSpec fontSpecVar Description This command opens a Windows Common Fontdialog It allows a user to select a font face size and attributes After the user closes the dialog the font chosen is contained in the receiver variable fontSpecVar fontSpec This parameter describes a font by name size and other attributes The font dialog opens with a best fit to this specification The user can then accept or adjust the font selection fontSpecVar This variable holds a font specification chosen by the user after the Fontdialog is closed
21. 150 listbox win vehicles vehicle selectVehicle 150 10 150 statictext win label mn 10 170 300 25 open Branch label handler for window as win win pets singleclickselect selectPet win vehicles singleclickselect selectVehicle wait selectPet win pets selection items print win label Pet gt items wait selectVehicle win vehicles selection items print win label Vehicl gt items wait loadData for x 0 to 2 read a pet x a next x for x 0 to 2 read a vehicle x a next x return data dog cat bird data car bike boat end The new way subroutines for event handlers In the example the code specifies the selectionMade subroutine to handle the user actions for the two listboxes in the window When the event handler is called it passes the window handle into the event handler 150 sub gosub loadData listbox win pets petS selectionMade 10 10 140 listbox win vehicles vehicle selectionMade 150 statictext win label mn 10 170 300 25 open Branch label handler for window as win win pets singleclickselect selectionMade win vehicles singleclickselect selectionMade wait selectionMade handles handlesS selection items select case case handleS win pets print win label Pet gt items case handleS win vehicles print win label Vehicl gt items
22. AS b rename file named a to b NEXT used with FOR NOMAINWIN keep a program s main window from opening north graphics command to set the current drawing direction NOT logical and bitwise NOT operator NOTICE open a notice dialog box ONCOMERROR set an error handler for serial communications ON ERROR set an error handler for general program errors OPEN opena file or window OPEN COMn open a communications port for reading writing OR logical and bitwise OR operator Iorigin text command to set origin lorigin text command to return origin OUT port byte send a byte to a port OUTPUT purpose parameter in fileopen statement Ipaste text command to paste text from clipboard pie graphics command to draw pie section piefilled graphics command to draw filled pie section place graphics command to locate pen Platform special variable containing platform name PLAYWAVE plays a wav sound file PLAYMIDI plays a midi sound file POPUPMENU pops up a menu posxy graphics command to return pen position print graphics command to print hard copy PRINT print to a file or window PrintCollate user choice in printerdialog PrintCopies number of copies chosen in printerdialog PRINTERDIALOG open a printer selection dialog box PrinterFont returns or sets the font used with LPRINT PrinterName name of printer PROMPT open a prompter dialog box PTR data type for calldll and structs PUT h n puts a random access r
23. If the user clicked the Cancel button this variable contains an empty string The string variable contains this information facename size attributes arial 14 italic courier new 12 bold FONT SPECIFICATIONS FaceName The facename is case insensitive so Arial is the same as ARIAL and arial To specify a font which has spaces in its name use underscores in place of the spaces like this Courier New becomes Courier_New or ignore the uppercase letters and type courier_new Size in Points Specify a point size as above by using a single size parameter A point is 1 72 of an inch so there are 72 points in an inch A font that is 14 points high is not the same size as a font that is 14 pixels high Size in Pixels To specify font size by pixel rather than by point include parameters for both width and height in the font command Ifthe width parameter is set to 0 the default width for that font face and height is used Here are some examples that set font size by point and by pixel specify just a point size with a single size parameter print fontExample font Arial 14 specify a width and height in pixels with two size parameters print fontExample font Arial 8 15 specify a height and let Windows pick the width for compatibility with earlier versions of Liberty BASIC print fontExample font Arial 0 15 Attributes Any or all of these attributes modifiers can be added italic
24. Run menu When run with Lite Debug a program will run as usual and you will not see the Debug window If the program encounters an error during execution the Debug window will pop up with the problem line of code highlighted This incredibly handy feature allows you to isolate errors quickly Lite Debug in Action To see it in action type the following code into the Liberty BASIC editor for x 10 to 0 step 1 print 10 x next x Now choose Lite Debug from the RUN menu The program will run normally at first and print the following in the main window 11111111 e 42857143 66666667 lt 3 733333333 o OD AHA aa ta ta ta 0 When the value of x gets to 0 the program halts with an error The Debug window will pop up with the title Debugging a ZeroDivide The problem line of code will be highlighted in the code pane of the debugger print 10 x A quick check of the variable list in the top pane shows that x is equal to 0 Substituting the value of x in the highlighted line of code shows that it is print 10 0 It is not possible to divide by 0 so the expression 10 0 has caused the program to stop running You now know that you can fix the problem by preventing the value of x from reaching 0 by changing the loop target from 0 to 1 for x 10 to 1 step 1 print 10 x next x Running the corrected code by choosing Lite Debug will cause the program to run and since there is no longer an error the
25. Set a custom size mainwin 40 20 for x 1to4 for y 0 to 9 print y next y next x print print 1 This screen is forty columns print 2 and twenty lines for x 3 to 19 print x next x Clearing the Mainwin The CLS statement clears previous text from the mainwin show a range of values for x 0 to 4 cls print The sine of x 0 1 to x 1 for y 0 1 to 1 step 0 1 print sine x y sin x y next y input Press enter for more go next x end Locating Text Using LOCATE in the mainwin causes text to be printed at the x y location specified These coordinates refer to the column and row of text not to screen pixels This command functions in the same way as the QBasic LOCATE command and is used to position text on the mainwin Here is a short demo plot a wave for x 1 to 50 i i 0 15 locate x 12 int cos i 10 princ wey next x Print TAB n Liberty BASIC 4 has the ability to use the TAB function for formatting output n is the character location where the next output will be printed tab 7 causes the next output to print beginning at column character 7 while tab 21 causes the next output to print beginning at column 21 show how tab works print x tab 7 sine tab 21 cosine for x 1 to 10 print x tab 7 sin x tab 21 cos x next x end Printing columns with commas A new feature of Liberty BASIC 4 is the use of commas for columnar printing
26. The extension begins with a dot and may include any alpha numeric characters A button contained on a window whose handle is win will have win as the first part of its handle Examples of button handles are as follows win no extension win okay win 1 win cancel win bmpbutton2 label This parameter specifies the caption that will appear on the button It may be expressed as a literal text string or as a string variable See String Literals and Variables returnVar returnVar is expressed as one word and it is not enclosed in quotes It cannot be expressed as a string variable It must begin with a letter but it can contain numerals as well If returnVar is set to a valid branch label enclosed in square brackets then a button click will cause program execution to continue at the specified branch label The code that follows the branch label will be executed when the button is pressed If returnVar is the name of a subroutine then that subroutine will be activated when the button is clicked and the button handle will be passed into the subroutine as an argument See also Controls and Events If returnVar is not a valid branch label or subroutine name then the value of returnVar is available to be read when the program is halted at an input var statement The value will be placed into the specified variable An example appears below corner This parameter must be one of the following UL UR LL or LR It specifies which cor
27. UPPER s Description This function returns a copy of the contents of the string string variable or string expression s but with all letters converted to uppercase Usage print upperS The Taj Mahal Produces THE TAJ MAHAL USING USING templateString numericExpression Description This function formats numericExpression as a string using templateString The rules for the format are similar to those in Microsoft BASIC s PRINT USING statement but since using is a function it can be used as part of a larger BASIC expression instead of being useful only for display output directly The template string consists of the character to indicate placement for numerals and a single dot to indicate placement for the decimal point The template string must be contained within double quotation marks If there are more digits contained in a number than allowed for by the template string the digits will be truncated to match the template A template string looks like this amountS using 1234 56 As part of a larger expression notice Your total is using 1234 5 A template string can be expressed as a string variable templateS Ain amount using templateS 1234 56 Using may be used in conjunction with print The following two examples produce the same result amountS using t 123456 78 print amounts print using Hrttit 123456 78
28. _modal window must be closed before another window can gain focus Liberty BASIC Window Types There are four types of windows available These four types include style variations as specified above The styles of these windows can be changed if the STYLEBITS command is issued before the command to open the window Here are the descriptions of the four window types Window Windows of type window are the most used and useful windows used by Liberty BASIC programmers They can contain any of the controls They can have a sizing frame or omit it They can have a titlebar or they can appear with no titlebar They can include a menu but they do not have to have a menu It is also possible for the user to hit the TAB key to move focus from one control to the next in a window of type window Graphics Windows of type graphics are especially suited to displaying graphics and graphical sprites They are not intended to contain controls and some controls do not work properly when placed in a graphics window A sizing frame and scrollbars are optional in a graphics window Dialog Windows of type dialog are similar to windows of type window in that they can contain all of the other controls except menus Menus cannot be placed on a dialog window Dialog windows allow the user to hit the TAB key to move focus from one control to the next A dialog can have a default button that is activated when the user hits the ENTER key For this reason t
29. handle locate x y width height This command is for a graphicbox not a graphics window and it repositions the control in its window This is effective when the control is placed inside a window of type window The control will not update its size and location until a refresh command is sent to the window See the included RESIZE BAS example program print handle north This command sets the current direction to 270 north Zero degrees points to the right east 90 points down south and 180 points left west print handle pie w h angle1 angle2 This command draws a pie slice inside an ellipse of width w and height h The pie slice will begin at angle1 and sweep clockwise angle2 degrees if angle2 is positive or sweep counter clockwise angle2 degrees if angle2 is negative print handle piefilled w h angle1 angle2 This command draws a pie slice inside an ellipse of width w and height h The pie slice will begin at angle1 and sweep clockwise angle2 degrees if angle2 is positive or sweep counter clockwise angle2 degrees if angle2 is negative The pie slice is fillled with the color specified using the BACKCOLOR command print handle place X Y This command positions the pen at XY No graphics will be drawn even if the pen is DOWN print handle posxy xVar yVar This command assigns the pen s current position to xVar amp yVar print handle print This command sends the plotted image to the Windows Print Ma
30. input Enter another number b print The smaller value is min a b See also MAX MKDIR Description The MKDIR function attempts to create the directory specified If the directory creation is successful the returned value is 0 If the directory creation was unsuccessful a value indicating a DOS error is returned Usage create a subdirectory named temp in the current directory result mkdir temp if result lt gt 0 then notice Temporary directory not created Note See also RMDIR NAME a AS b NAME StringExpr1 AS StringExpr2 Description This command renames the file specified in the string expression StringExpr1 to StringExpr2 StringExpr1 can represent any valid filename that is not a read only file and StringExpr2 can be any valid filename as long as it doesn t specify a file that already exists Usage rename the old file as a backup name rootFileName fre as rootFileNameS bak open a new file and write data open rootFileName fre for output as disk NOMAINWIN Description This command instructs Liberty BASIC not to open a main window the mainwin for the program that includes this statement Some simple programs which do not use separate windows for graphics or text may use only the mainwin Other programs may not need the mainwin to do their thing If the mainwin is not needed including NOMAINWIN somewhere in the program source code prevents the wind
31. is returned if the Yes button is pressed and the string no is returned if the No button is pressed by the user The result is placed in responseVar Usage quit bring up a confirmation box to be sure that the user wants to quit confirm Are you sure you want to QUIT answer if answer no then mainLoop end Multiline Message If line breaks are inserted into the message it appears as a multiline message Line breaks are represented by chr 13 The CONFIRM dialog window is sized to accomodate the message Please Confirm This operation will reset defaults we All changes will be lost This operation is not reversable Continue anyway c This operation will reset defaults chr 13 c c All changes will be lost chr 13 c c This operation is not reversable chr 13 c c Continue anyway confirm c answers COS n COS n Description This function returns the cosine of the angle n The angle n should be expressed in radians Usage for c 1 to 45 print The cosine of c is cos c next c Tip There are 2 pi radians in a full circle of 360 degrees A formula to convert degrees to radians is radians degrees divided by 57 29577951 Note See also SIN and TAN CURSOR Description The CURSOR command makes it easy to change the mouse pointer to be one of 5 predefined shapes NORMAL the default pointer ARROW the standard Win
32. main print eXpert mode main print Main Selection Menu The conditional lines can be shortened to one line as follows if instr Nn mode gt 0 then print Novice mode else print eXpert mode Some permitted forms are as follows if a lt b then statement else statement if a lt b then label else statement if a lt b then statement else label if a lt b then statement statement else statement if a lt b then statement else statement statement if a lt b then statement goto label else statement if a lt b then gosub label1 else gosub label2 Any number of variations on these formats are permissible The a lt b BOOLEAN expression is of course only a simple example chosen for convenience It must be replaced with the correct expression to suit the problem IEF THEN END IF is another form using what are called conditional blocks This allows great control over the flow of program decision making Here is an example of code using blocks if qtySubdirs 0 then print None goto noSubs end if A block is merely one or more lines of code that are executed as a result of a conditional test There is one block in the example above and it is executed if qtySubdirs 0 It is also possible to use the ELSE keyword as well with blocks if qtySubdirs 0 then print None else print Count of subdirectories qtySubdirs end if This type of coding is easy to read and understand There are t
33. open STYLEBITS demo for window popup as main main pw please main rjust on the right wait WINDOW AND CONTROL STYLE CONSTANTS window styles some also work for controls _WS_BORDER Creates a window that has a thin line border _WS_CAPTION Creates a window that has a title bar includes the WS_BORDER style _WS_HSCROLL Creates a window that has a horizontal scroll bar _WS_MAXIMIZE Creates a window that is initially maximized _WS_MAXIMIZEBOX Creates a window that has a Maximize button _WS_MINIMIZE Creates a window that is initially minimized Same as the WS_ICONIC style _WS_MINIMIZEBOX Creates a window that has a Minimize button _WS_VSCROLL Creates a window that has a vertical scroll bar button styles _BS_LEFT Left justifies the text in the button rectangle _BS_RIGHT Right justifies text in the button rectangle _BS_RIGHTBUTTON Positions a radio button s circle or a check box s square on the right side of the button rectangle editbox textbox styles EG CENTER Centers text in a multiline edit control _ES PASSWORD Displays an asterisk for each character typed into the edit control EG RIGHT Right aligns text in a multiline edit control listbox styles _LBS_MULTICOLUMN Specifies a multicolumn list box that is scrolled horizontally _LBS_ SORT Sorts strings in the list box alphabetically statictext styles _SS_CENTER Specifies a simple rectangle and centers the text in the rectangle _SS_RIGHT Sp
34. with the LOADBMP command so that they can be displayed with the DRAWBMP command Usage open NViewLib dll for DLL as nv fileS test jpg calldll nv NViewLibLoad file AS ptr 1 as short hImage AS short handle of loaded image close nv loadbmp newimage hiImage open Drawbmp Test for graphics as main print main drawbmp newimage 10 10 wait when program exits unloadbmp newimage See also BMPSAVE UNLOADBMP LOCATE LOCATE has two uses The first usage listed here locates a control on its parent window The second usage is for the mainwin only LOCATE CONTROLS print handle ext locate x y width height or print handle ext locate x y width height Description This command for windows of type window causes a control to be moved and or resized Always issue a REFRESH command after the LOCATE command to cause the window to be repainted to reflect the control s new position and size For a demonstration see Resize bas Usage print handle ext locate 20 12 300 200 or x 20 y 12 width 300 height 200 print handle ext locate x y width height See also RESIZEHANDLER REFRESH Window and Dialog Commands LOCATE IN MAINWINDOW locate x y Description Using LOCATE in the mainwin causes text to be printed at the x y location specified These coordinates refer to the column and row of text not to screen pixels This command functions in the same was as the
35. 18 statictext member City 10 70 60 18 statictext member State 10 100 50 18 statictext member Zip 10 130 30 18 textbox member name 90 10 180 25 textbox member address 90 40 180 25 textbox member city 90 70 180 25 textbox member state 90 100 30 25 textbox member zip 90 130 100 25 button member amp OK memberOK UL 10 160 WindowWidth 300 WindowHeight 230 open Enter Member Info for dialog as member print member trapclose quit wait memberOK print member name contents name print member address contents addresss print member city contents city print member state contents states print member zip contents zips er chr 13 note name cr address cr city cr _ stateS cr zips notice Member Info cr notes quit close member end For information on creating controls with different background colors see Colors and the Graphical User Interface Stop Description Identical to END and used interchangeably STOPMIDI STOPMIDI Description This command stops a MIDI file that is being played with the PLAYMIDI command It must be issued before a new PLAYMIDI command can be issued and to stop MIDI files from playing when a program ends See also PLAYMIDI MIDIPOS STR n STR numericExpression Description This function returns a string expressing the result of
36. 4 1 2002 print date 1 1 1901 print date April 1 2002 print date Apr 1 2002 Here is a small program that demonstrates the last two implementations of the date function It determines the number of shopping days until the holiday season today dateS days target date 12 25 2003 subsititute current year and desired holiday print Shopping days left print target today Dechex DECHEX number Description Returns a string representation of a decimal number converted to hexadecimal base 16 Usage print dechex 255 prints FF See also HEXDEC DefaultDir Description A string variable that contains the default directory for the running Liberty BASIC program The format is drive dir1 or drive dir1 dir2 etc There is no backslash appended to the DefaultDir variable Usage print DefaultDir As used with a FILES statement files DefaultDirS txt infoS As used to access a text file in the same directory as the program Notice that the backslash must be added to the beginning of the filename open DefaultDir S readme txt for append as f print Ef Sample close f DIM array DIM array size or DIM array size size DIM array1 size1 array2 size2 array3 size3 etc Description DIM sets the maximum size of an array Any array can be dimensioned to have as many elements as memory allows If an array is not DiMensioned explicitly
37. 400 graphichbox w g 0 0 400 300 open sprite test for window nf as w A window that contains sprites must include a graphicbox or it must be a graphics window Only one graphicbox or graphics window in a program may use sprites BACKGROUND FROM LOADED BITMAP There are several ways to designate a background image One way is to use a loaded bitmap as the background The bitmap must first be loaded with the LOADBMP command loadbmp landscape bgl bmp The BACKGROUND command sets the bitmap called landscape to be the background print w g background landscape Note that simply setting the background bitmap does not cause the background image to display onthe screen See the section on Drawing and Collision Detection to find out about updating the display NOTE ABOUT BACKGROUND BITMAP SIZE If the loaded bitmap is the same width and height as the graphicbox or the client area of the graphics window it is used just as it is If the width of the bitmap is less than the width of the graphicbox or graphics window then it is stretched to fit If the height of the bitmap is less than the height of the graphicbox or graphics window then it is stretched to fit Here is an example The width of the following bitmap is greater than the width of the graphicbox so it remains unchanged The height of the bitmap is less than the height of the graphicbox so it is stretched to fit GraphicBox Result Original Bitmap IMPORTANT N
38. 7 For all sprites that are to cycle through frames of animation issue a CYCLESPRITE command 8 For all sprites that are to have a size different from the actual bitmap image size issue a SPRITESCALE command 9 For all sprites that are to appear in a different orientation issue SPRITEORIENT commands 10 For all sprites that are to move automatically with each frame of animation issue a SPRITEMOVEXY command DURING ANIMATION 11 Scroll background if desired with the BACKGROUNDXY command 12 Move sprites individually if desired with the SPRITEXY command 13 Change scale cycling orientation and visibilty of sprites as required by the specifics of the program with SPRITESCALE SPRITEORIENT SPRITEVISIBLE SPRITECYCLE 14 Obtain current location of desired sprites with the SPRITEXY command 15 Retrieve lists of sprites that have collided with designated sprites with the SPRITECOLLIDES command 16 Place frames of animation on the screen with the DRAWSPRITES command Simple Demo Program This simple demo draws a background and sprites on the screen using GETBMP to set up the bitmaps for sprite animation The program scrolls the background moves the sprites automatically checks for collisions and acts when the sprites collide nomainwin WindowWidth 410 WindowHeight 450 UpperLeftX 50 UpperLeftY 5 graphicbox graphicbox open Animation for window nf as w print w draw backg print w g print w g
39. BASIC 4 introduces the GLOBAL statement to create global variables Variables declared as GLOBAL can be seen everywhere in a program See GLOBAL The special system variables like WindowWidth WindowHeight etc now have true global status GLOBALS are specified and used like this global true false maxNum true 1 false 0 maxNum 128 Mathematical Operations ABS n Description This function returns n the absolute value of n n can be a number or any numeric expression Usage print abs 5 produces 5 print abs 6 13 produces 7 print abs 2 4 produces 6 print abs 3 produces 3 print abs 3 2 produces 1 5 print abs 5 75 produces 5 75 SQR n Description This function returns the square root of the number or numeric expressioin n Usage print The square root of 2 is print SOQR 2 EXP n Description This function returns e n with e being 2 7182818 Usage print exp 5 produces 148 41315 LOG n Description This function returns the natural log of n Usage print log 7 produces 1 9459101 INT n Description This function removes the fractional part of number which is the part of the number after the decimal point leaving only the whole number part behind Usage retry input Enter an integer number gt 1 if i lt gt int i then print i isn t an integer R nter goto retry end if Ww MAX expr1 expr2 Description This f
40. Enable parity checking RS Disable detection of RTS request to send Other defaults DTR detection is disabled XON XOFF is disabled binary mode is the default To set the in and out communications buffers each port has its own set the variable Com notice the uppercase C to the desired size before opening the port Changing the variable after opening a port does not affect the size of the buffers for that port while it is open set the size of the communications buffers in and out to 16K each Com 16384 Usage Notes To open com port 2 at 9600 baud 8 data bits 1 stop bit and no parity use this line of code open com2 9600 n 8 1 for random as commHandle It is recommended that you set the the timeout on the DSR line to 0 so that your program doesn t just freeze when waiting for data to come in Todo this we can add a dsO for DSR 0 timeout as below Notice we use a different communications speed in this example open com2 19200 n 8 1 ds0 for random as commHandle Remember that when a modem dials and connects to another modem it negotiates a cpnnectopm speed In the case of 14400 speed modems you need to specify 19200 as the connection speed and let the modems work it out between themselves during the connect This is because 14400 is not a baud rate supported by Windows and you ll find that QBASIC doesn t directly support 14400 baud either Once the port is open sending data is accomplished by printing to the
41. Joy2z Joy2button1 Joy2button2 KILL s delete file named s A C D F G K L M N P R S T Z Command Reference L M Commands and Keywords A C D F G K L M N P R S T Z LEFT s n first n characters of s LEN s length of s LET var expr assign value of expr to var line graphics command to draw line Iline text command to return text from specified line in texteditor control lines text command to return number of lines in texteditor control LINE INPUT get next line of text from file LISTBOX add a listbox to a window ListboxColor sets or returns listbox color LOADBMP load a bitmap into memory LOC handle return current binary file position locate locate a control LOF h returns length of open file h or bytes in serial buffer LOG n retums the natural logarithm of n LONG data type for calldll and structs LOWERS s s converted to all lowercase LPRINT print to hard copy MAINWIN set the width of the main window in columns and rows MAPHANDLE change window handles dynamically MAX return the greater of two values MENU adds a pull down menu to a window MID amp return a substring from a string MIDIPOS return position of play in a MIDI file MIN return the smaller of two values MKDIR make a new subdirectory Imodified text command to return modified status Command Reference A C D F G K L M N P R S T Z Command Reference N P Commands and Keywords A C D F G K L M N P R S T Z NAME a
42. NAME VISIBLE SCALE ORIENTATION CYCLE LOCATION MOTION TRAVEL Z ORDER The properties VISIBLE and NAME are discussed in Designating Sprites Sprites have several other properties that can be set by the programmer CYCLE Liberty BASIC will automatically cycle through the image list for a sprite if given the CYCLESPRITE command The command also requires the sprite s NAME and a value for the frame count A value of 1 will cause the sprite to cycle through all images in its list from first listed to last listed A value of 1 will cause the sprite to cycle through all of its images in the reverse order from which they were listed A value equal to one of the images in the list will cause the sprite to cycle to that image To cycle forward through all images print w g cyclesprite smiley 1 or backwards print w g cyclesprite smiley 1 For the example with three frogs Liberty BASIC will cycle through these three images when drawing frames of animation loadbmp frogl frogl bmp loadbmp frog2 frog2 bmp loadbmp frog3 frog3 bmp print w g addsprite frog frogl frog2 frog3 print w g cyclesprite frog 1 CYCLE ONCE Adding ONCE to the CYCLESPRITE command causes the sprite to cycle through its frames of animation either forward or backward only one time and then stop at the last or first frame After the single cycle through frames the sprite will appear as the last or first frame
43. OKM OIA sovs ADmMWPLETSYM en w eg Mee OKOM EMQG ONKA ia ODA eOnmssom ZS OE Oude E QO DE GOUD S OR OWL mate Zo OR JEU DEL 60 S55 ONE PILIOS cal SIT CO tre eA E ege Aso E evIvehe Cree ROL AOOOOM E O8x 00 E e D e Sei Ovoee HODeokXhs kOm AL eA sooneemoa Loe IU seus Recs Ces Sins AOS E OOOeE MOM LOOM IxM e sSoOHXSQem e b itb epobo BOS bees Geiben AAA S POOOemxNHsexOm D00 zoo ON Slt p lt aeOKOXMy BAB ue S eee be BOS K Z ec MR OOHEY e KHEOO AR pn MrLee OB eoem DEL FHOMESOM AC PDAM Som 2 GOAR D Keel 2 SE Dessmm ZS K G o e er eOxXeeono 100 vap Det OH EI amp OXmeesDeessen Arne MESSE ale OOWOASSOOKE OSS ODN De BOR Cal B m P P er aD E B B 3 OIeuUHArKeeps ODEA BO HomO SMMM oye BA HM GR SOAM SSM me OURA Jm meee S on Qoo Reeve LOS op Bi S Ju SL amp Ue a Cs Bye pes BB omemoen2 002 DOUG wPIL9 eH omeOeeoxoOm Diff Tele EE TT Te Ge ot BRE Gab e OXY MOOS DLT E 0 BBZ Oeem z Ox wen BB
44. Qbasic LOCATE command and is used to position text on the mainwin Here is a short demo plot a wave for x 1 to 50 i i 0 15 locate x 12 int cos i 10 prank m next x LOF h LOF handle Description This function returns the number of bytes contained in the open file referenced by handle Usage open autoexec bat for input as 1 qtyBytes lof 1 for x 1 to qtyBytes print inputS 1 1 next x close 1 end LOC h LOC handle Description The LOC handle function retrieves the current position of the file pointer when a file whose handle is specified has been opened for BINARY access The current position of the file pointer is used when reading or writing data to a binary file See also SEEK Usage open myfile ext for binary as handle get the current file position fpos loc handle LOG n Description This function returns the natural logarithm of n Usage print log 7 produces 1 9459101 LOWER3S s LOWER s Description This function returns a copy of the contents of the string string variable or string expression s but with all letters converted to lowercase Usage print lower The Taj Mahal Produces the taj mahal LPRINT LPRINT expr Description This statement is used to send data to the default printer as determined by the Windows Print Manager A series of expressions can follow LPRINT there does not need to be an
45. The using function for Liberty BASIC 3 has been modified so that it rounds its output like PRINT USING does in other BASICs Usage print a column of ten justified numbers for a 1 to 10 print using rnd 1 1000 next a sample output from the routine above 72 06 134 601 19 697 91 5 82 619 22 UpperLeftX Description The special variables UpperLeftX and UpperLeftY specify the distance inpixels from the topleft of the display for the next opened window For example the following code will open a graphics window whose upper left corner is located 50 pixels from the left of the display and 25 pixels from the top of the display UpperLeftX 50 UpperLeftY 25 open test window for graphics as testHandle input r See also WindowWidth Window Height UpperLeftY Description The special variables UpperLeftX and UpperLeftY specify the distance inpixels from the taoleft of the display for the next opened window For example the following code will open a graphics window whose upper left corner is located 50 pixels from the left of the display and 25 pixels from the top of the display UpperLeftX 50 UpperLeftY 25 open test window for graphics as testHandle input r See also WindowWidth Window Height VAL s VAL stringExpression Description This function returns a numeric value for stringExpression if stringExpression represents a valid numeric value or if it
46. Variables Literal Strings A string literal always starts with a quotation mark and always ends with a quotation mark No quotation marks are allowed in between the starting and ending quotation marks Here is an example that prints a string literal in the mainwin print Hello World The program above would produce this in the mainwin Hello World String Variables There are special variables for holding words and other non numeric character combinations These variables are called string variables they hold strings of characters Characters are Letters of the alphabet abcdefghijkimnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ Digits 0123456789 Any other special symbols like lt gt 2 amp etc String variable names must end with a dollar sign Text is assigned to a string variable using the equals sign This example assigns Hello World to the string variable hello and then prints it in the mainwin hello Hello World print hellos The program above produces this in the mainwin Hello World NOTE A string can have zero characters Such a string is often called an empty string In BASIC an empty string can be expressed in a string literal as two quotation marks without any characters between them For example noCharactersHere is the name of our string variable let noCharactersHere Concatenation Two strings of text can be joined together concatenated either as vari
47. Window A rectangle portion of the display which is being used for a specific program Word Processor A computer program that helps you create change format and print documents such as letters and reports WYSIWYG Stands for What You See Is What You Get It is pronounced wizzy wig It means that what you see on your screen while you edit your file looks the same as what you get when you print the file Zipped file A file that has been made smaller using a compression utility Overview of Liberty BASIC v 4 Welcome to our Liberty BASIC overview In this section we will introduce you to Installing and Uninstalling How to install Liberty BASIC and how to remove it from your system Registering Liberty BASIC Why and how to register this software The Liberty BASIC Editor This is the place where BASIC programs are written and compiled Editor Preferences How to configure the Liberty BASIC editor The Liberty BASIC INI file How editor preferences are stored Writing Programs Getting started Freeform Creating windows with the visual designer called Freeform GUI Programming Using windows and controls such as buttons textboxes etc Using the Debugger How to debug find errors in Liberty BASIC programs Lite Debug Run programs normally and pop up the debugger when there is an error Compiler Reporting The Liberty BASIC Editor looks for potential problems in code Creating a Tokenized File Converting code to
48. World he text window s font 1 font hely 16 37 change prin ct ct read line 1 print 1 line 1 input 1 string S print The first line is print strings input Press Return r close the window close 1 Proper use of semicolons and the print command In the following example semicolons are omitted in printed commands They are used to force carriage returns when printing text It is also possible to omit the word print and to omit the comma after the handle when printing to a text window or texteditor This means that the word print and the comma following the handle are optional nomainwin open Example for text as 1 print 1 trapclose quit Carriage return suppressed by semicolon print 1 Hello this line will have a carriage return 1 World this command omits the word print 1 font courier new 12 print some more text into the window no carriage return print 1 This is a font called print text with carriage returns print 1 Courier new blank line print 1 1 Done wait quit close 1 end Note Most of the commands listed below work with windows of type text and also with the texteditor control except where noted Here are the text window commands print handle cls This command clears the text window of all text print handle contents varname print handle contents han
49. a TKN format to be used by the runtime engine Using the Runtime Engine How to create programs for distribution Icon Editor How to create an icon to incorporate into the runtime engine Lesson Browser Using the lesson browser to learn and to teach Using a Different Code Editor Running Liberty BASIC from the command line Using Inkey Trapping and evaluating keyboard input Using Virtual Key Constants with Inkey A more advanced method for evaluating keyboard input Reserved Word List A list of keywords commands functions and variables used by Liberty BASIC Error Messages Understanding the errors that halt program execution Error Log Explained How to use the error log file Port I O Controlling hardware ports Making API and DLL Calls Extending the language with Dynamic Link Libraries TroubleShooting What to do when a program misbehaves Installing and Uninstalling Liberty BASIC To install Liberty BASIC simply run the setup program Either accept the default installation directory folder or specify another directory folder Liberty BASIC will be installed in this folder Subfolders containing files needed by Liberty BASIC will be installed in the main Liberty BASIC directory Do not modify these subfolders or the files contained in them To uninstall Liberty BASIC run uninstall exe which is found in the folder containing Liberty BASIC This folder also contains a file called uninstall ini Be car
50. a single item single line text entry control to a window It is useful for generating forms and getting small amounts of user input in the form of text Liberty BASIC 4 adds PASSWORD and RIGHTJUSTIFY commands See below handle ext The handle part must be the same as for the window that contains the textbox control The ext part must be unique for the textbox xpos amp ypos This is the position of the textbox in x and y from the upper left corner of the window wide amp high This is the width and height of the textbox in pixels Textbox commands print handle ext a string This sets the contents of the textbox to be a string Any previous contents of the textbox are overwritten To clear a textbox of text print a blank string to it print handle ext print handle ext contents varName This retrieves the contents of the textbox and places them into the variable varName print handle font fontName pointsize Tihs sets the font of the textbox to the specified name and size If an exact match cannot be found then Liberty BASIC will try to match as closely as possible with size taking precedence over the facename in the match Note that a font sized too large to fit in the textbox will not allow the text it contains to be displayed For more on specifying fonts read How to Specify Fonts Also see below for Dead Textbox Problem Example print handle font Times New Roman 10 print handle ex
51. also The Liberty BASIC Editor Notification Confirm on exit of Liberty BASIC This causes Liberty BASIC to ask Are you sure when you try to close down the Liberty BASIC editor Display execution notice This causes Liberty BASIC to display an execution complete notice in a program s main window if it has one when it is finished running Starting up Start Liberty BASIC Editor full screen This causes Liberty BASIC to open the editor so that it fills the whole screen whenever Liberty BASIC is started up Load on startup No file This causes Liberty BASIC to start with no text in the editor and a filename of untitled bas Most recent file This causes Liberty BASIC to start with the file the user was editing when it was last shut down This file This causes Liberty BASIC to start with the file specified in the text field Compiling Show Compile Progress Dialog This causes a popup dialog to appear when compiling for Run Debug Lite Debug or Make TKN file The user can press a cancel button on the dialog to abort the compile action Enable Compiler Reporting This tells the compiler to apply certain compile checks and list any interesting results at the bottom of the Liberty BASIC editor window See Compiler Reporting Create BAK File On Run Debug This activates a backup mechanism so that every time a program is run it is also backed up into a file of the same name but with a BAK extension The user can a
52. becomes Times_New_Roman and the font Courier New becomes Courier_New Example print handle font Times New Roman 10 For more on specifying fonts read How to Specify Fonts print handle insert varname This command inserts the contents of the variable at the current caret text cursor position leaving the selection highlighted print handle line n string Returns the text at line n In the code above n is standing in for a literal number If n is less than 1 or greater than the number of lines the text window contains then an empty string is returned After this command is issued the line s text is contained in the variable string This sample code retrieves the contents of line number 7 and places them into a variable called string print textwindow line 7 string print h lines countVar This command returns the number of lines in the text window placing the value into the variable countVar print handle modified answer This command returns a string either true or false that indicates whether any data in the text window has been modified The variable answer holds this returned string This is useful for checking to see whether to save the contents of the window before closing it print h origin columnVar rowVar This command causes the current text window origin to be returned The origin is the upper left corner of the texteditor or textwindow When a text window is
53. bold strikeout and underscore Usage open a font dialog fontdialog arial 10 italic chosenFont if chosenFont lt gt then open Font sample for graphics as font print font down font chosenFont print font AaBbCcDdEeFfGgHhIiJgj print font trapclose closeFont wait end if end closeFont close font end See also How to Specify Fonts FOR EXIT FOR NEXT Description The FOR NEXT looping construct provides a way to execute code a specific amount of times See the section below on the proper way to exit a loop before the counter variable reaches the limit A starting and ending value are specified for var 1 to 10 BASIC code next var In this case the BASIC code is executed 10 times with var being 1 the first time 2 the second and on through 10 the tenth time Optionally and usually var is used in some calculation s in the BASIC code For example if the BASIC code is print var 2 then a list of squares for var will be displayed upon execution The specified range could just as easily be 2 TO 20 instead of 1 TO 10 but since the loop always counts 1 ata time the first number must be less than the second The way around this limitation is to place STEP n at the end of for FOR statement for index 20 to 2 step 1 BASIC code next index This loops 19 times returning values for index that start with 20 and end with 2 STEP can be used with both p
54. can use a function which also contains a variable named counter in its code When the function is used the counter variable in the calling code doesn t lose its value when the function changes the value of its variable named counter They are in fact different variables although they share the same name Variables passed into subroutines may be passed by reference which allows them to be changed in the subroutine or function and the change is reflected in the main program For more on passing byref please see below Here is an example that uses a function set my variable counter for counter 1 to 10 print loop counter next counter end function loop limit for counter 1 to limit next counter loop counter end function Exceptions to the variable scoping mechanism include the following things which are globally visible everywhere in a Liberty BASIC program Arrays Things with handles files windows DLLs communications ports Structs GLOBAL In general variables used in the main program code are not visible inside functions and subroutines Variables inside functions and subroutines are not visible in the main program Liberty BASIC 4 introduces the GLOBAL statement to create global variables Variables declared as GLOBAL can be seen everywhere in a program See GLOBAL The special system variables WindowWidth WindowHeight UpperLeftX UpperLeftY ForegroundColor BackgroundColor ListboxColor TextboxCo
55. change modes between step animate and run This allows you to use the run button to debug a program and when it hits a TRACE 2 command in the code it will automatically drop down into step mode USING THE DEBUGGER You can write a short program that shows how to use the debugger In the Liberty BASIC editor click on the File menu and select New File You ll see Liberty BASIC 4 0 untitled bas OF EX File Edit Run Setup Help Cs e a BB Ze De Orr On Type in the following simple program for x 1 to 1000 print x next x Liberty BASIC 4 0 untitled bas for x 1 to 1000 print x next x Now click on the debug button E The program runs and a special Debugging window also appears Position the two windows so that you can see them both Now focus on the debugger Debugging Debugging OF EX Code File Edit gt Em A fd 9 UpperLefty Version 4 0 WindowHeight WindowWvidth TF Ontop Manually scroll variables V Show default variables 08 07 20 Execution stopped Notice the pane on the top This lists your program s variables There s a lot of information in there already because each program comes with some special variables already declared Scroll down to the bottom of the list where the variable named x is located Focus on this variable for this example UpperLeftyYy Version WindowHeight Windowidth There are buttons
56. code does not specify the values for these special variables their defaults will be 320 and 360 respectively After a resize event that is trapped by the resizehandler command these variables contain the width and height of the client area of the window the client area is the workspace of the window that is contained within the sizing frame border or titlebar See resize bas for an example of this usage Usage The following example will open a graphics window 250 pixels wide and 100 pixels high WindowWidth 250 WindowHeight 100 open test window for graphics as testHandle input r See also UpperLeftX UpperLeftY Resizehandler Winstring Ptr Winstring structName pointer struct Winstring pointer Description The WINSTRING function returns a string when a function returns a pointer to a string This function is especially useful when retrieving the text string from a STRUCT that has been altered by a function or when an API function returns a pointer to a text string in memory Usage struct demo name as ptr length as long call DoDemo hello print Uppercase string is print winstring demo name struct print Length of string is print demo length struct sub DoDemo avar demo name struct upperS avarS demo length struct len avar end sub OUTPUT Uppercase string is HELLO Length of string is 5 enagusis om2 Gm em CC Se soso GDOOgeR an 3 y A Kk
57. comma delimited item in a file on its own line open inputto test txt for input as test whil of test 0 print inputto test wend close test Inputto directly to an array You can use inputto to fill an array directly dim array 500 filedialog Open txt fileS open fileS for input as test whil of test 0 array total inputto test print arrayS total total totalt l if total gt 500 then exit while wend close test for i 0 to total print arrayS i next end See also INPUT INPUTS h n Line Input INSTR a b n INSTR string1 string2 starting Description This function returns the position of string2 within string1 If string2 occurs more than once in string1 then only the position of the leftmost occurance will be returned If the starting parameter is included then the search for string2 will begin at the position specified by starting Usage print instr hello there lo produces 4 print instr greetings and meetings eetin produces 3 print instr greetings and meetings eetin 5 produces 16 If string2 is not found in string1 or if string2 is not found after starting then INSTR will return 0 print instr hello el 3 produces 0 and so does print instr hello bye INT n Description This function removes the fractional part of n a number leaving only the whole number part behind
58. conjunction with print The following two examples produce the same result amountS using H t 123456 78 print amounts print using 123456 78 The using function for Liberty BASIC 3 has been modified so that it rounds its output like PRINT USING does in other BASICs Usage print a column of ten justified numbers for a 1 to 10 print using t xrnd 1 1000 next a sample output from the routine above 72 06 244 28 133 74 99 64 813 50 529 65 601 19 6 1 Ov RR WO oO J N O vo N N HEXDEC value Description Returns a numeric decimal from a hexadecimal number expressed in a string Hexadecimal values are represented by digits 0 F the hexadecimal number can be preceded by the characters amp H The hexadecimal string must be enclosed in quote marks Usage print hexdec FF or print hexdec amp HFF DECHEX number Description Returns a string representation of a decimal number converted to hexadecimal base 16 Usage print dechex 255 prints FF EVAL code and EVAL code Description Liberty BASIC now has two functions for evaluating BASIC code inside a running program The eval function evaluates the code and returns a numeric value and the eval function works the same way but returns a string value Both will execute the very same code but the string function converts the result to a string if it isn t already one
59. control also resizes print handle cls This clears the texteditor of all text print handle contents varname print handle contents handle This has two forms as described above The first form causes the contents of the text window to be replaced with the contents of varname and the second form causes the contents of the text window to be replaced with the contents of the stream referenced by handle this is the handle of a file opened for INPUT This second form is useful for reading large text files quickly into the window Here is an example of the second form open Contents of AUTOEXEC BAT for text as aetext open C AUTOEXEC BAT for input as autoexec print aetext contents autoexec close autoexec stop here input a print handle contents string This returns the entire text contained in the control After this command is issued the entire text is contained in the variable string print handle copy This causes the currently selected text to be copied to the WINDOWS clipboard print handle cut This causes the currently selected text to be cut out of the text window and copied to the WINDOWS clipboard print handle font fontName pointsize This sets the font of the text window to the specified name and size If an exact match cannot be found then Liberty BASIC will try to match as closely as possible with size taking precedence o
60. controls After all controls have been given a LOCATE command the window must be given a REFRESH command to cause it to be repainted New dimensions After the resizehandler has been activated the new dimensions of the window workspace are contained in the variables WindowWidth and WindowHeight Use these dimensions to calculate the desired size and placement for the controls in the window See also LOCATE REFRESH Window and Dialog Commands Usage See the example program RESIZE BAS and the demo below resizehandler using a sub button main close Close quit UL 10 10 open example for window as main main resizehandler resized main trapclose quit wait sub resized handle notice strS WindowWidth strS WindowHeight end sub sub quit handles if instr handles then handle left handleS instr handle 1 end if close handle end end sub RESTORE RESTORE RESTORE branchLabel Description RESTORE will reset the reading of DATA statements so that the next READ will get information from the first DATA statement in the program or the first DATA statement in a function or subroutine if this is where the RESTORE is executed Example show me my data in all uppercase while string lt gt end read strings print upperS string wend stringS clear this for next while wend loop now reset the data reading to the beginning restore show me my data in all lowerca
61. creating a new BASIC program or a new LESSON If LESSON is chosen a default empty lesson displays in the lesson browser It looks like this Liberty BASIC v4 0 untitled Isn File Edit Run Setup Help BEZ S a slale ze al 1 E Enter a helpful comment about the lesson here g place your ex camp le code her A right click in the TOC pane on the left pops up a menu with choices to give the lesson a name or to add a chapter If Rename is chosen from this menu an input box will pop up The desired name should be entered there If New Chapter is chosen from the menu an input box will pop up to input name the chapter 7 Liberty BASIC 4 0 untitled Isn Fie Edit Run Setup Help Del E Zei El 210 Untitled Les Enter a helpful comment about the lesson here X New Chapter Rename place your example code here Once a chapter has been added a right click activates a new menu with choices to rename the chapter delete it or add a section A click on the lesson name chapter name or section name in the TOC causes the comments for that item to display in the comment pane and the code to display in the code pane It is easy to add to or edit the comments and code The lesson is saved by choosing SAVE from the FILE menu It will be saved with the extension an Using a different code editor You may use a third party editor to create and modify Liberty BASIC code You can even write your own code editor in Lib
62. doSomething This similar example evaluates to FALSE because a is not less than 4 so the program will not advance to doSomething OR at least one of the conditions must be met for the test to evaluate to TRUE a 14 bz H If a lt 4 OR b 5 then doSomething In this code at least one of the conditions a must be less than 4 OR b must be equal to 5 must evaluate to TRUE for the program to branch to doSomething Since the example shows that b is equal to 5 the program will advance to doSomething because at least one of the conditions evaluates to TRUE XOR only one of the conditions must be met for the test to evaluate to TRUE a 14 bz H If a lt 4 XOR b 5 then doSomething In this code only one of the conditions a is less than 4 OR b is to 5 must evaluate to TRUE for the program to branch to doSomething In the example only the second condition evaluates to true so the program will advance to doSomething a 2 be 5 If a lt 4 XOR b 5 then doSomething In the second XOR example both conditions evaluate to true so the program will NOT advance to doSomething NOT reverses the value If NOT a lt 4 AND b 5 then doSomething In this code both of the conditions a must NOT be less than 4 AND b must be equal to 5 must evaluate to TRUE for the program to branch to doSomething BOOLEAN TRUTH TABLE Inputl OP Input2 Result A A ES 3 Lo ao SN Z e FORO A O
63. end if Instead in Liberty BASIC it looks like this Liberty BASIC no elseif if sis boom bah then print Yippie else if la dee da then print So what end if end if Select Case Statement Many BASICs have a Select Case statement and Liberty BASIC 3 adds that capability also It is a good alternative when many possible conditions must be evaluated and acted upon The Select Case construction also provides a Case Else statement for implementing a routine when the evaluated condition meets none of the cases listed For more see SELECT CASE SELECT CASE is a construction for evaluating and acting on sets of conditions The syntax for Select Case is SELECT CASE var CASE x basic code goes here CASE y basic code goes here CASE z basic code goes here CASE else basic code goes here END SELECT Details SELECT CASE var defines the beginning of the construct It is followed by the name variable that will be evaluated The variable can be a numeric variable or a string variable or an expression such as a b CASE value following the SELECT CASE statement are individual CASE statements specifying the conditions to evaluate for the selected variable Code after the case statement is executed if that particular case evaluates to TRUE There is no limit to the number of conditions that can be used for evaluation CASE ELSE defines a block of code to be executed if the selected value
64. expression referred to a field which is undefined for a struct which is defined named root in this example Errors when using serial communications There are a handful of run time error messages which terminate program execution These usually correlate to API function call failures that occur when attempting different operations In this case the error is reported by Windows but the description of the reported error is generated by Liberty BASIC Here is a list of the error messages Port must be open SetCommState failed Unable to get DCB Output queue full Unable to send RTS Unable to clear RTS Unable to clear DTR Unable to set DTR Byte size too small Byte size too large Invalid port or port not open Unable to get max port Unable to set break The device is already open The device identifier is invalid or unsupported The device s baud rate is unsupported The specified byte size is invalid The default parameters are in error The hardware is not available is locked by another device The function cannot allocate the queues The device is not open The following run time errors are indications of more subtle problems in Liberty BASIC If you see one of these errors send email to carlg libertybasic com describing in as much detail how the error happened If you have BASIC code that can reproduce the error please include it in your message Index n is outside collection bounds The collection is empty Object is not in
65. first opened the result would be row 1 column 1 The result is contained in the variables rowVar and columnVar print handle origin column row This command forces the origin of the window to be row and column This means that the row and column specified will appear in the upper left corner of the texteditor or text window Row and column must be literal numbers To use variables for these values place them outside the quotation marks preserving the blank spaces like this print handle origin column row print handle paste This causes the text in the WINDOWS clipboard if there is any to be pasted into the text window at the current cursor position print handle select column row This command puts the blinking cursor at column row Column and row must be literal numbers To express them as variables place the variables outside the quotation marks and preserve the blank spaces like this print handle select column row print handle selectall This causes everything in the text window to be selected highlighted print handle selection selected This command returns the highlighted text from the window The result will be contained in the variable selected print handle setfocus This causes Windows to give input focus to this control This means tht ifsome other amtrol in the same window was highlighted and active this omtrol now becomes the highlighted and a
66. for new messages The TIMER is deactivated by setting a time value of 0 and no branch label There is only one timer The elapsed time value and or branch label to execute can be changed at any time by issuing a new TIMER command There are 1000 milliseconds in one second A value of 1000 causes the timer to fire every one second A value of 500 causes the timer to fire every half second and so on Usage Branch Label Handler set a timer to fire in 3 seconds using branch label event handler timer 3000 itHappened wait here wait itHappened deactivate the timer timer 0 confirm It happened Do it again answer if answer then reactivate the timer timer 3000 itHappened wait end if end Subroutine handler set a timer to fire in 3 seconds using subroutine event handler timer 3000 itHappened wait here wait sub itHappened deactivate the timer timer 0 confirm It happened Do it again answer if answer then reactivate the timer timer 3000 itHappened end if end sub Be Careful Ifthe program attempts to execute more code within a timer routine than can be executed in the timer interval the timer ticks build up and the program will keep executing them as quickly as it can This might make the program appear to have locked up To avoid a lock up place a SCAN command within the timer routine so that the program knows when the user activates other controls or closes a window Titlebar Descript
67. for the possible debugging modes gt E Ki CH E W Resume Stop Steplnto Step Over StepOut Animate Resume runs your program at full speed in the debugger While in this mode you won t see variables change or program source code highlighted Stop will cause your program to stop and it will highlight the line where it stopped and it will show the current variable contents Step Into will execute the next line of code If the next line is inside a subroutine or function it will follow execution into the subroutine or function Step Over will execute the next line of code It will not step into subroutines or functions but skips over them Step Out will run until the current subroutine or function exits and then stops to show the next line of code and variables Animate runs your program showing each line as it executes and also updating variables as it runs Click on the Step Into button You ll see that the first line of code is executed The the variable x is no longer 0 but 1 Also the next line of code is highlighted Debugging Debugging iof x Code File Edit A f 3 UpperLeftyY Version WindowHe ight WindowWidth E Wi e or 360 zj Po Execute IT Ontop Manually scroll variables MV Show default variables 1 to 1000 08 15 02 Stepped Now click on the Step Into button again Notice that the value of x gets printed to the program window and also the next line o
68. function deg2rad num deg2rad asn 1 90 num end function ACS n Description This function returns the arc cosine of the number or numeric expression n The return value is expressed in radians Usage print The arc cosine of 0 2 is acs 0 2 ASN n Description This function returns the arc sine of the number or numeric expression n The return value is expressed in radians Usage print The arc sine of 0 2 is asn 0 2 ATN n Description This function returns the arc tangent of the number or numeric expression n The return value is expressed in radians Usage print The arc tangent of 0 2 is atn 0 2 COS n Description This function returns the cosine of the angle n The angle n should be expressed in radians Usage for c 1 to 45 print The cosine of c is cos c next c SIN ni Description This function returns the sine of the angle n The angle n should be expressed in radians Usage for t 1 to 45 print The sine of t is sin t next t TAN n This function returns the tangent of the angle n The angle n should be expressed in radians Usage for t 1 to 45 print The tangent of t is Cant next t Numbers and Strings Liberty BASIC has several functions that convert numeric values and strings VAL stringExpression Description This function returns a numeric value for stringExpression if stringExpression represents a valid numeric value or if it
69. g addsprite guy smiley The spritename is used to refer to this sprite when setting its properties or issuing commands to it The image for a designated sprite can be changed by issuing the ADDSPRITE command again loadbmp frown frown bmp print w g addsprite guy frown None of the properties of the guy sprite change when the image is changed VISIBILITY All added sprites will be drawn in each frame of animation The SPRITEVISIBLE command is used to specify whether a sprite is visible or not A sprite is hidden by issuing SPRITEVISIBLE the sprite name and off print w g spritevisible guy off A sprite is shown by issuing SPRITEVISIBLE the sprite name and on print w g spritevisible guy on INVISIBLE SPRITES AND COLLISIONS Invisible sprites still trigger collisions For more see the section on Drawing and Collision Detection MULTIPLE VERSIONS OF A SPRITE It is possible to have several different versions of a sprite image When the image moves it cycles through these versions to create the illusion of real movement The versions might look like this The individual bitmaps for the sprite images must be loaded with LOADBMP The bitmaps for the frog look like this The code to load them looks like this loadbmp froot frogl bmp loadbmp frog2 frog2 bmp loadbmp frog3 frog3 bmp print w g addsprite frog frogl frog2 frog3 Now the sprite with the NAME of frog contains three individ
70. in the directory that contains your copy of Liberty BASIC To order online visit http Awww libertybasic com The Liberty BASIC Editor When you start Liberty BASIC you will see a window like this Liberty BASIC 4 0 C Program Files Liberty BASIC 4 0 welcome bas Bisi x File Edit Run Setup Help Cs Gm A pe Ze Bl oO Thanks for helping us t t Liberty BASIC v4 0 alpha This is our second alpha test version This means that some more features will be added before our final release It also means that you should keep frequent backup copies of your work when developing with LB4 just in case Kal Since this is an alpha version we have two goals di Pl e let them to complete as 1 possible in your cription some code and a portion of the error log file if appropriate Oh and did I say THANKS some of the ideas in this release are n and probably novel in some ways If they f weird or wrong I don t mind hearing it If you can think of any way to tweak or improve these ideas give me a shout I may This is where code is written and this is where you will spend most of your time when writing Liberty BASIC programs Notice the various pull down menus along the top of the window These are for loading and saving files editing running debugging setting up configuration and getting help Running an example program Let s begin our exploration of Liberty BASIC by running one of the sample progra
71. in the main window Commas placed between outputs signal the starts of new columns Commas contained within quotation marks do not signal new columns a demonstration of printing columns using commas print x sine cosine for x 1 to 10 print x sin x cos x next x end Text Window Commands The commands in this topic work with the text window and texteditor control Anything printed to a text window is displayed exactly as sent To distinguish commands sent to a text window from text that is to be diplayed in the window the character should be the first character in the string It is no longer necessary to add a semicolon to the end of a printed command line to suppress a carriage return The semicolon at the end of a printed command is now optional When printing text rather than commands a carriage return is added to the text with each print statement unless the statement ends with a semicolon Note for instructions on sending text to the printer see LPRINT Using variables in text commands Literal values are placed inside the quotation marks print handle line 3 strings Variables must be places outside the quotation marks with blank spaces preserved lineNum 3 print handle line lineNum string See also Understanding Syntax how to use literals and variables in commands For example open a text window open Example for text as 1 print Hello World in the window print 1 Hello
72. item to be chosen popupMenu popupmenu amp Square Spiral asSquare _ amp Triangular Spiral asTriangle wait asSquare print geo cls home down color red for x 1 to 120 print geo go x turn 87 next x wait asTriangle print geo cls home down color blue for x 1 to 120 print geo go y x turn 117 next x wait quit close geo end Notice that the amp character placed in the title and text items for the menu determines the accelerator placement for each menu item See also MENU PRINT PRINT handle expression expression s Description This statement is used to send data to the mainwin to a disk file or to other windows A series of expressions can follow PRINT each separated by a semicolon Each expression is displayed in sequence Ifthe data is being sent to a disk file or to a window then handle must be present PRINTing to the mainwin After the expressions are displayed the cursor that blinking vertical bar will move down to the next line and the next time information is sent to the window it will be placed on the next line down To prevent the cursor from moving immediately to the next line add an additional semicolon to the end of the list of expressions This prevents the cursor from being moved down a line when the expressions are displayed The next time data is displayed it will be added onto the end of the line of data displayed
73. lowerS string wend data Sally Sells Sea Shells By The Sea Shore partTwo data Let s DOM y Only This A Second Time end end Reading DATA into Arrays DATA is READ into variables It cannot be READ directly into arrays To fill arrays with DATA items first READ the item into a variable then use that variable to fill an index of the array wrong read numericArray 1 correct read numl numericArray 1 numl Error Handling An attempt to read more DATA items than are contained in the DATA lists causes the program to halt with an error Notice that in the examples above an end tag is placed in the DATA and when it is reached the program stops READing DATA This is an excellent way to prevent errors from occuring If an end tag or flag of some sort is not used be sure that other checks are in place to prevent the READ statement from trying to access more DATA items than are contained in the DATA statements See also READ RESTORE DATA File Operations Liberty BASIC supports sequential binary and random access file operations See also OPEN Sequential Files Binary Files Random Access Files CLOSE INPUT INPUTS INPUTTO LINE INPUT PRINT Files can be created with the OPEN command Files can be renamed with the NAME command Files can be removed with the KILL command When a file is being read the EOF function returns 0 if the end of the file has been reached other
74. numericExpression Usage age 23 ageS strS age price 2 99 prices strS price totalApples 37 print Total number of apples is str totalApples STRUCT STRUCT name field1 as type field2 as typez2 Description This statement builds an single instance of a specified structure thatis required when making some kinds of API DLL calls This does not declare a type of structure but it creates a single structure Here is an example STRUCT statement that builds a Windows rect structure used in many Windows API calls create the structure winRect struct winRect _ orgX as long _ orgY as long _ extentX as long _ extentY as long A value is assigned to a field of a structure in a similar way to variable assignements The name of the struct is used first followed by a dot then by the name of the field being accessed then by another dot and last by the word struct This example assigns a value of 100 to the orgX field of the struct winRect winRect orgX struct 100 The structure s fields may be used in the same manner as any other variable print winRect orgX struct Or newOriginX offsetX winRect orgX struct Some API calls require the size of a struct to be passed as a parameter Determine the length size of a struct with the LEN function sizeStruct len winRect struct When passing a structure in a CALLDLL statement specify type as struct as is done in this
75. pane takes up a significant amount of workspace at the bottom of the Liberty BASIC editor It can be hidden by right clicking the mouse within the report pane and choosing Hide from the menu Creating a tokenized file Creating a tkn file from a bas source file makes a file that starts up much faster very important for large files can be distributed royalty free using Liberty BASIC s runtime engine gold license only can be added to the Liberty BASIC s Run menu as an external program and run instantly by selecting it from that menu How to Tokenize a Source Code File You can create a tkn file from one of the sample programs Reopen the drawing program used in The Liberty BASIC Editor section of this document Liberty BASIC 4 0 draw1_bas Iof x File Edit Run Setup Help von fe 2 U Cs e a BB Ze nomainwin lineThickness 1 menu 1 Object cLine setForLine sEllipse se menu 1 Color Red colorRed Yellow colorYell menu 1 Drawing Line Thickness lineThickness bmpbutton 1 bmp redbttn bmp colorRed UL 5 5 bmpbutton 1 bmp yllwbttn bmp colorYellow UL 4 bmpbutton 1 bmp grnbttn bmp colorGreen UL 75 hrmnhut ton Ri hmnihluehrt t n bmn TenlarRluel T uA Now pull down the Run menu and select Make TKN File for instance Liberty BASIC v4 0 draw1_bas e setForLine Ellipse se colorRed Yellow colorYell me Th
76. previously Usage Produces print hello world hello world print hello hello world print world age 23 print Ed is age years old Ed is 23 years old When sending data to a disk file and in regard to the use of the semicolon at the end of the expression list the rules are similar although the result is not displayed on the screen Use of a semicolon at the end of a line suppresses the carriage return line feed that causes text to be printed on the next line When printing to a window the expressions sent are usually commands to the window or requests for information from the window For more information see GUI Programming PRINTERDIALOG ei Ss Add Printer PRINTERDIALOG Description This command opens the standard Windows Common Printer Dialog If the user chooses a printer and accepts the next print job will go to this printer Accepting a printer also sets the global variables PrinterName PrintCollate and PrintCopies to reflect what the user chose for the Printer Name Collate and Copies If no printer is accepted then PrinterName is set to an empty string PrinterFont To set the font used when LPRINTing text use the PrinterFont variable See also PrinterFont PrintCopies If the printer driver can handle printing multiple copies PrintCopies will be set to 1 and the program only needs to Iprint the text one time If the printer driver cannot handle multiple copy printing the
77. print w g print w g w g 0 0 400 300 w s 0 301 100 100 trapclose quit round down fill blue color red backcolor red boxfilled 200 150 getbmp landscape 0 0 399 299 set background print w dra prin prin prin WwW Gh GG CI masks prin prin ct ct ct oO K H CT TTT TTT RB Se EE W gr S sy w background landscape sprite and mask down fill white backcolor black color black place 0 40 boxfilled 80 80 place 20 20 circlefilled 18 place 60 20 circlefilled 18 color yellow backcolor yellow place 20 60 circlefilled 18 color black backcolor black size 4 Set 12 55 set 28 55 size 1 place 20 67 ellipsefilled 20 5 Getbmp balll 0 0 40 80 add sprite set auto move print print sprite print print print addsprite guy balll spritemovexy guy 3 2 color pink backcolor pink place 60 60 circlefilled 18 color blue size 4 print w s print w s print w s print w s print w s add sprite2 print w g print w g print w g set 54 55 set 66 55 color darkpink backcolor darkpink size 1 place 60 67 ellipsefilled 20 7 Getbmp ball2 40 0 40 80 set auto move addsprite girl ball2 spritexy girl 380 280 spritemovexy girl 2 2 move sprites scroll background check for collisions ms timerScroll 100 wait scroll if ms
78. program called run time errors Here are some compile time errors Syntax error This means that some error was made while typing in a BASIC statement You should examine the line and look for typing mistake Type mismatch error This means that you tried to use a string where a number should be used or a number where a string should be used Here are some run time errors Branch label exampleLabel not found The program tried to GOTO or GOSUB to a label that doesn t exist Float divide by zero exception The program tried to divide a number by zero which is not possible to do File filename not found This error can occur when attempting to load a bitmap image from a disk file into memory using the LOADBMP statement and when no file of the specified filename is found to exist Bitmap named bitmapname not found This error can occur when attempting to save a bitmap from memory to a disk file using the BMPSAVE statement or when attempting to use the DRAWBMP command and a bitmap name is specified which doesn t exist in the program s memory Control type fonts are set with FONT face Name width height An error was made specifying the font for a control controls which return this error include button textbox radiobutton checkbox undefined struct structname An expression referred to the name of an undefined struct see the help file for information about the STRUCT statement root field struct undefined An
79. select a font face size and attributes NOTICE This dialog gives the user a message and it includes an OK button It stays onscreen until the user clicks the OK button PRINTERDIALOG This dialog allows the user to select a printer and the number of copies of a document to print PROMPT This dialog has a brief text message and a textbox that allows a user to enter a small amount of text It also contains an OK button and a CANCEL button Please see the topics for the individual dialogs for pictures and details on their use Sounds There are several ways to play sounds using Liberty BASIC BEEP The BEEP command plays the system default wav file This is often a DING sound See BEEP PLAYWAVE The PLAYWAVE command plays a wav sound file on disk See PLAYWAVE PLAYMIDI The PLAYMIDI command plays a midi sound file on disk See PLAYMIDI Mouse Keyboard and Joystick Liberty BASIC can read mouse events and keyboard input when a graphics window or graphicbox is used See Reading Mouse Events and Keystrokes Liberty BASIC can read the x y and z coordinates of up to two joysticks and it can read the status of the joystick buttons See READJOYSTICK Command Reference A C Commands and Keywords A C D F G K L M N P R S T Z ABS n absolute value of n ACS n arc cosine of n addsprite sprite command to add a sprite AND bitwise boolean AND operator APPEND purpose parameter in fileopen statement AS used in calldll and str
80. single and double dim d arrays SPACE n returns a string of n spaces Sprites all about using sprites in Liberty BASIC spritecollides sprite command to discover collisions spriteimage sprite command to set sprite image spritemovexy sprite command to auto move sprite spriteoffset sprite command to offset x y location of sprite spriteorient sprite command to orient sprite spriteround sprite command to change method of collision detection spritescale sprite command to set sprite s scale spritetoback sprite command to put sprite at bottom of z order spritetofront sprite command to put sprite at top of z order spritetravelxy sprite command to move sprite to desired position spritevisible sprite command to set visibility of sprite spritexy sprite command to set location of sprite spritexy sprite command to return location of sprite SQR n details about getting the square root of a number STATICTEXT add a statictext control to a window STOP marks end of program execution STOPMIDI stops a MIDI file from playing STR n returns string equivalent of n stringwidth graphics command to return width of text string STRUCT builds a structure used in calling of APIs and DLL functions STYLEBITS add or remove style bits from a control SUB defines a subroutine Command Reference A C D F G K L M N P R S T Z Command Reference T Z Commands and Keywords A C D F G K L M N P R S T Z TAB n cause tabular printing i
81. string array that contains the contents of the combobox Be sure to load the array with strings before opening the window If some time later it becomes necessary to change the contents of the combobox simply change the contents of the array and send a RELOAD command to the combobox The index numbers of items in the array may not match the index numbers of the same items in the control The control is loaded from the array and the first index used in the control is 1 No empty strings are loaded into the control so only array items that contain text are loaded eventHandler This is the branch label or subroutine where execution begins when the user selects an item from the combobox by clicking it See also Controls and Events xPos amp yPos These coordinates specify the the distance in x and y in pixels of the combobox from the upper left corner of the window wide amp high These parameters determine the width and height in pixels of the combobox Height in this case refers to the length of the selection list when the combobox s button is clicked not to the size of the initial selection window which is dependant upon the size of the font Here are the commands for combobox print handle ext contents This command sets the contents of the field part of the combobox to the string after the print handle ext contents text This retrieves the contents of the text field of the combobox into the variable called tex
82. text capabilities rather than a statictext control IMPORTANT NOTE In order to draw you must make sure that the drawing pen in down and not up See below for more information Here is an example using a graphics window open Drawing for graphics as handle print handle home center the pen print handle down ready to draw print handle fill red fill the window with red print handle circle 50 draw a circle print handle flush make the graphics stick wait And here is an example using a graphicbox graphicbox handle gbox 10 10 150 150 open Drawing for window as handle print handle gbox home center the pen print handle gbox down ready to draw print handle gbox fill red fill the graphics area red print handle gbox circle 50 draw a circle print handle gbox flush make the graphics stick wait Because graphics can involve many detailed drawing operations Liberty BASIC allows mutliple commands to be listed in a single command statement if they are separated by semicolons The following example shows several graphics commands each on its own line print handle up print handle home print handle down print handle north print handle go 50 The same commands can be issued on a single line and will execute slightly faster print handle up home down north go 50 If text is displayed using graphics commands a semicolon may not be used after
83. the actual sprite images are generally elliptical or round in shape A SPRITEROUND command is issued like this print w g spriteround smiley INVISIBLE SPRITES AND COLLISIONS Invisible sprites still trigger collisions Ifa sprite is to be out of action for a time in addition to being made invisible it should also be located to a spot outside the active viewing area Invisible sprites may be used to set up a screen area for collision detection For instance if it is necessary to know when a sprite is touching a doorway an invisible sprite can be placed at that spot on the screen so that it can be checked for collisions REMOVING SPRITES It is sometimes necessary to remove sprites from the collection of sprites so that they no longer appear and so that they no longer trigger collisions This might be done after a sprite collides with another sprite so that it is no longer in play in the game Remove sprites with the REMOVESPRITE command print w g removeSprite smiley DETECT SPRITE LOCATION The SPRITEXY command retrieves the current location of a sprite If a CENTERSPRITE command has been issued the x y location returned indicate the center of the sprite otherwise they indicate the upper left corner Just like the SPRITECOLLIDES command it can have two forms It can be followed by an input statement with two receiver variables for the x and y coordinates of the sprite or the receiver variables can be included inside the quo
84. then the array will be limited to 11 elements 0 to 10 Non DiIMensioned double subscript arrays will be limited to 100 elements 0 to 9 by 0 to 9 The DIM statement can be followed by a list of arrays to be dimensioned separated by commas Usage Example 1 print Please enter 10 names for index 0 to 10 input names name index nameS next index Example 2 Dimension three arrays at once dim arrayOne 100 arrayTwo 100 5 arrayThree 100 100 The FOR NEXT loop in the example above is limited to a maximum value of 10 because the array names is not dimensioned and therefore is limited to 11 elements numbered 0 10 To remedy this problem add a DIM statement as in the example below Notice that it is not necessary to use all available index numbers In the example the array is filled beginning at index 1 ignoring index 0 dim names 20 print Please enter 20 names for index 1 to 20 input names names index name next index Double subscripted arrays can store information more flexibly dim customerInfo 10 5 print Please enter information for 10 customers for index 0 to 9 input Customer name gt infoS customerInfoS index 0 info input Address gt infoS customerInfoS index 1 infos input City gt info customerInfo index 2 infos input State gt infoS customerInfo index 3 infos input Zip gt infoS customerInfo index 4 info
85. to label the Filedialog window It appears in the titlebar of the window If the window label specified has the word save in it then the save style of the dialog will be used instead of the open style This means that the button to approve the file selection will say save rather than open will have buttons that say OPEN and CANCEL filedialog Open text file txt fileName S print File chosen is fileNames will have buttons that say SAVE and CANCEL filedialog Save As txt fileName S print File chosen is fileNames templateString This parameter is used as a filter so that only files matching a wildcard are listed To view all file types the templateString is To access multiple extensions in a filedialog separate the desired extensions with a semicolon character like this example which displays files with extensions of both BAS and BAK files in the dialog filedialog Open code file bas bak fileNameS receiverVar When the user selects a filename the resulting full path specification will be placed into receiverVar This parameter contains an empty string if the user canceled the Filedialog Usage The following example produces a dialog box asking the user to select a text file to open filedialog Open text file txt fileNames If a file named c liberty summary txt was selected and Open was clicked then program execution would resume after placing the s
86. trapclose quit print 1 down place 20 40 print 1 Open the desired sprite image print 1 A mask will be added to the sprite print 1 las you watch print 1 This might take time for large images print 1 Images larger than the window print 1 will be cut off print 1 If it is satisfactory choose print 1 Save As from the File menu hWindow hwnd 1 loop input aVars quit close l end openSprite if hBitmap lt gt 0 then unloadbmp bm print 1 cls end if filedialog Open Sprite bmp bitmaps if bitmapS then notice No bitmap chosen goto loop end if print 1 cls loadbmp bm bitmaps hBitmap hbmp bm print 1 down drawbmp bm 0 0 bmpheight HeightBitmap bitmapS bmpwidth WidthBitmap bitmap P c g rint 1 drawbmp bm 0 bmpheight all MakeMask bmpwidth bmpheight hWindow oto loop saveAs print 1 getbmp SpriteMask 0 0 bmpwidth 2 bmpheight filedialog Save As bmp savefile if savefileS then notice No filename specified goto loop end if bmpsave SpriteMask savefile notice Sprite and mask saved as savefileS goto loop VkKK KKK KKK KKK KEUNCTIONS amp KKK KK KK KKK KK KK function WidthBitmap name open name for input as pic picS input pic 29 close pic WidthBitmap asc mid pic 19 1 _ asc mid pic 20 1 256 end function function HeightBitmap name
87. until a different cycle command is issued This is useful for animations such as explosions print w g cyclesprite frog 1 once SCALE A sprite may be scaled to a percentage of its original width and height with the SPRITESCALE command A percentage of 200 will cause the sprite to appear twice the original width and height while a percentage of 50 will cause it to be half as large as the width and height of the loaded bitmap To change the size of a sprite to be one and one half times the width and height of the loaded bitmap print w g spritescale smiley 150 ORIENTATION By default sprites are shown just as they appear in the loaded bitmap It is easy to cause them to appear as a mirror image of the loaded bitmap or flipped or rotated 180 degrees It is not possible to rotate 90 or 270 degrees so these rotations will require separate sprites bitmaps Sprites can have alterations in both scale and orientation at one time print w g spriteorient smiley normal print w g spriteorient smiley flip print E g spriteorient smiley mirror print w g spriteorient smiley rotatel80 POSITION AND MOVEMENT A sprite can be moved to the x y position indicated in the SPRITEXY command The following example places the sprite named smiley at x 100 y 137 print w g spritexy smiley 100 137 Liberty BASIC will automatically move a sprite each time a new frame is drawn if the SPRITEMOVEXY command is issu
88. which can be a disk file a window a dynamic link library or a serial communications port The command must be told what to open for what purpose and a descriptive unique name or handle must be assigned to it so that other functions can access the open device Handles must always begin with to identify them as such and to distinguish them from other variables The details for using the OPEN statement are shown below It will be necessary to refer to the individual topics for complete explanations for using OPEN with the various devices Note Any device that is opened during the normal operation of the program must be closed before program execution is finished See CLOSE Changing the handle of a device dynamically at runtime can be accomplished with the MAPHANDLE command device The device to be opened may be one of the following file If the device to be opened is a file the device parameter must be a valid disk filename This may be expressed as a string variable or as a literal text expression enclosed in quotes For more on coding file specifications see Path and Filename purpose Files may be opened for the purpose of INPUT OUTPUT APPEND RANDOM or BINARY access The final LEN n parameter applies to files opened for RANDOM access For more on opening files please see File Operations usage open c readme txt for input as f window If the device to be opened is a window the device parameter will become the capti
89. 01 print date 4 1 2002 36980 days since Jan 1 1901 for given date print dates 36980 04 01 2002 mm dd yyyy string returned when given days since Jan 1 1902 Date Math Here is a small program that demonstrates one way that Date can be used with math operators today dateS days target date 1 1 2004 subsititute value for next year print Days until the new year A print target today Time this form of time produces this format print time time now as string 16 21 44 print time seconds seconds since midnight as number 32314 print time milliseconds milliseconds since midnight as number 33221342 print timeS ms milliseconds since midnight as number 33221342 Time Math Here is a small program that demonstrates one way that Time can be used with math operators get start time startTime time ms do some computations for i 1 to 40000 X xt next get end time endTime times ms print Computations took print endTime startTime milliseconds end Text and Characters This section of the help system explains the use and manipulation of text as literal strings of characters or as string variables It also details commands for text windows and text editors String Literals and Variables Manipulating Characters Text Mode Display in the Mainwin Text Commands See also Sending text to the Printer with LPRINT String Literals and
90. ASIC v2 0 the placement of windows and dialog boxes is more or less the same Previous versions had two different helpfile sections to describe how window and dialog placement worked The size and placement of any window can be set before it is opened If no size and placement statements are specified before a statement to OPEN a window Liberty BASIC will pick default sizes There are four special variables that can be set to select the size and placement of windows UpperLeftX UpperLeftY WindowWidth WindowHeight The width and the height of the display screen can be retrieved with these variables DisplayWidth DisplayHeight The values set for UpperLeftX and UpperLeftY determine the number of pixels from the upper left corner of the screen to position the window Often determining the distance from the upper left corner of the screen is not as important as determining the size of the window If UpperLeftX and UpperLeftY values are not set the window will appear at a default location determined by Windows WindowWidth and WindowHeight can be set to the number of pixels wide and high desired for window These must be set before the OPEN statement for the window Once the size and placement of a window are set the window may be opened with an OPEN statement Here is an example openStatus UpperLeftX 32 UpperLeftY 52 WindowWidth 190 WindowHeight 160 open Status Window for window as stats print Screen width is
91. Contents Liberty BASIC v4 0 Help Document Copyright 1992 2003 Shoptalk Systems http www libertybasic com Windows is a registered trademark of Microsoft Corporation in the United States and other countries What s New What s new in version 4 Overview An overview of Liberty BASIC The Liberty BASIC Language Syntax and Usage for the Liberty BASIC Language Gui Programming Creating and using Graphical User Interfaces Command Reference Detailed Listing of Liberty BASIC Commands API and DLL Making API and DLL calls in Liberty BASIC Graphical Sprites Sprites for Games and Graphics Port I O Controlling Hardware Ports File Operations Accessing Disk Files Mathematics Mathematical Operators and Functions Text Text Manipulation and Functions Graphics Using Color and Drawing Commands Troubleshooting Solving Problems Registering Liberty BASIC Why and how to register Liberty BASIC http www libertybasic com The official Liberty BASIC web site Installing Liberty BASIC Installing and uninstalling Liberty BASIC What s New What s new in Liberty BASIC 4 additions and modifications that make Liberty BASIC 4 different from previous versions of Liberty BASIC Improvements to DIM TAB n Printing columns with commas Handle Variables Subs for Event Handlers Global Variables BYREF Passing by reference MAPHANDLE changing the handle of open devices Graphics window scrollbar changes EVAL code E
92. Debug window will not pop up The main window will display the following results and the program will terminate without an error 1 Ve REPLI TEL 1 25 42857143 66666667 a 233333333 Compiler Reporting Liberty BASIC includes compiler reporting This means that the compiler has a mechanism for reporting interesting things it finds while compiling For example if a program has two variable names which are the same except for their capitalization the reporter will find this Here is an example maxnum 200 MaxNum 300 Running a program containing the lines above anywhere in the code causes the compiler reporting pane to appear at the bottom of the Liberty BASIC editor It reports similar variables maxnum MaxNum Another example is variables with similar names If one variable is called names but there is another string variable name no letter ei a common mistake the reporter will mention it name Carl names Gundel If the lines above are contained in a program the compiler reports string variable warning nameS names Here is a picture of the compiler report pane Liberty BASIC v4 0 alpha 2 Alyce Watson untitled bas Iof x I U File Edit Run Setup Help DSU e a BO Ze axnum 200 MaxNum 300 name Carl names Gundel print maxnum String variable warning name names similar variables MaxNum maxnurm Hiding the Compiler Report Pane The compiler report
93. DisplayWidth print Screen height is DisplayHeight This will open a window 32 pixels from the left side of the screen and 52 pixels from the top of the screen and with a width of 190 pixels and a height of 160 pixels The screen resolution is contained in the special variables DisplayWidth and DisplayHeight A screen resolution of 800x600 pixels returns values of 800 and 600 respectively for DisplayWidth and DisplayHeight The sample code below prints the current screen resolution print Screen width is DisplayWidth print Screen height is DisplayHeight DisplayWidth and DisplayHeight can be used to compute values for WindowWidth and WindowHeight as in these examples WindowWidth DisplayWidth WindowHeight DisplayHeight 100 Window Types Liberty BASIC provides different kinds of window types Controls can be added to these windows as needed see help section Controls Menus Buttons Etc Here are the kinds of windows and the commands associated with them The way to specify what kind of window to open is as follows open Window Title for type as handle where type would be one of the descriptors below Style suffixes for window types not all suffixes are supported for each window type _fs window is sized to fill the screen nf window has no frame and cannot be resized by user _nsb window doesn t contain scroll bars _ins contains inset texteditor __popup window contains no titlebar or sizing frame
94. EM statement Note When using instead of REM at the end of a line the statement separator colon is not required to separate the statement on that line from its comment For example print Total dollar value dollarValue rem print the dollar value Can also be stated print Total dollar value dollarValue print the dollar value Notice that the colon is not required in the second form REFRESH print handle refresh Description This command is issued to a window of type WINDOW after the LOCATE command is used to move or resize controls It causes the window to be repainted For a demonstration see Resize bas See also RESIZEHANDLER LOCATE Window and Dialog Commands RESIZEHANDLER RESIZEHANDLER branch or RESIZEHANDLER subName Description This command sets up an event handler for the instance when the user resizes a window of type window This command is not useful for dialog windows graphics windows text windows or for windows without a sizing frame The resize event can be handled in a named branch or in a subroutine If a sub is used as the event handler the handle of the window being resized is passed into the sub set up a handler for when the user resizes a window print handle resizehandler branch OL es clear the resizing handler print handle resizehandler The branch that is activated for the resize event should contain the code to LOCATE the desired
95. ER is perfect for use with animation It will cause the branch label specified to be executed at the time interval specified in milliseconds There are 1 000 milliseconds in one second A half second interval would require the milliseconds parameter to be 500 A one quarter second interval would require a milliseconds parameter of 250 and a one tenth of a second interval would use a milliseconds parameter of 100 The following example causes a frame to be drawn every one tenth of a second TIMER 100 DrawFrame To turn off the TIMER use this TIMER 0 The TIMER can be activated or reactivated in the code as desired by repeating the TIMER command The time interval can be changed as can the branch label to execute when the timer fires Here is an example that could occur in the same program as the TIMER example above TIMER 250 DrawExplosion AN IMPORTANT NOTE ABOUT THE TIMER The cpu clock ticks 18 times per second This means that it ticks roughly every 56 milliseconds If the time interval is set to 56 milliseconds or less the resulting animation will run at a top speed of 18 frames per second Ifa program stops for any reason the timer ticks accumulate and the accumulated ticks fire off rapidly when the program action resumes This might happen when the program gives the user a notice message for instance If action is to stop for any reason it is necessary to issue a TIMER 0 command to stop the timer When the actio
96. ET MKI MKS MKD CVI CVS amp CVD that are required with Microsoft BASICs Note See also Random Files PUT and GET FILEDIALOG Open code file Look in G Liberty BASIC v3 02 Di oa DEI E EJ ll fonttest bas Ill MAYHEM bas zl DUNDATCH bas Fe E freeforn3_0210 bas multiwin bas E SEGMENT bas TE My Recent E Freeform3_0830 bas NEWCOLOR bas E selectcasethree bas te Geer GL PL App bas password bas e SIEVE2 bas TS E GLBLHNDL bas piano bas E SLOTMACH bas tt Il GRAFDEMO bas PIE bas E SPACESHP bas TL Desktop E graphics bas PLAYER bas il SPRGETXY bas we E HANOI bas POPMENLI2 bas E spriteclick bas Zei E IMITATE bas GSORTLB bas z SPRITEPV bas E INKEY bas RADIOBTN bas E SPRITTIM bas WOES Je ladder bas RBGROUP bas E SPRITTST bas a E lander bas RESIZE bas E SPRTTST2 bas WE E Ib3edit bas IS RNDTEST bas E SPRTTST3 bas y Kelt E E LOCATE bas rolodex1 bas E SORT bas A TEA KE MANDALA bas B as E stringFromHex bas wE E D LU WITT File name rolodex3 bas F Open Places K Files of type H bas Files D Cancel FILEDIALOG titleString templateString receiverVar Description This command opens a Windows Common Filedialog Liberty BASIC 3 uses long filenames and an explorer type filedialog The dialog lets a user navigate around the directory structure looking at filenames that have a specific extension and selecting one titleString This parameter is used
97. How to make API DLL calls Example Programs Using hexadecimal values Using Types with STRUCT and CALLDLL Passing Strings into API Calls Caveats TroubleShooting Low memory situtations Most computers today have enough memory to run Liberty BASIC If you find that you are getting low memory errors try the following Close other running Windows and DOS applications Reduce the size of your Smartdrive disk cache or eliminate it Increase the size of your Windows swapfile General Protection Faults Most general protection faults in Liberty BASIC are caused by Video drivers A major problem with environments like Windows and OS 2 video drivers are often immature and or incompletely implemented according to spec Try to get the most recent version of the Windows drivers for your video card If it isn t a showstopper for you try the standard 16 color drivers that come with Windows Low memory see above If you are getting a general protection fault in VSTUB EXE you need either a bigger swapfile more physical RAM or both Liberty BASIC Language This section of the help system deals with the the structure syntax and usage of the Liberty BASIC language It contains information on the following topics Logic and Structure Arrays and Variables File Operations Mathematics Text Usage Graphics Sprites API and DLL Calls Logical Line Extension Liberty BASIC supports a technique called logical line extension which a
98. Information for Port UO If your application uses INP and or OUT to control hardware ports you will need to distribute and install certain files on your user s system For detailed information see Port I O The LBASIC4 INI File Liberty BASIC stores default information in a very small text file named LBASIC4 INI This file is also read by the runtime engine RUN400 EXE if it is present One of the things that LBASIC4 INI manages is the default font used for the the Liberty BASIC development environment and for the runtime engine If you want your distributed application to use the same font that is set for the Liberty BASIC development environment then include the LBASIC4 INI file with your application If you want text printed to the printer to use the same printer font that is in use by the Liberty BASIC development environment then include the LBASIC4 INI file with the distribution Installing a Liberty BASIC Program You can distribute your programs on a set of disks or ona CDROM and ask the user to copy them to his hard drive You can also place all of the files into a zip archive This makes the distribution smaller and insures that all needed program files stay together The user then simply unzips the files into the folder of his choice There are freeware and commercial installation programs that can be used to install programs created with Liberty BASIC Search the internet and software download sites to find these programs Icon Edi
99. K Commands and Keywords A C D F G K L M N P R S T Z GET h n get random access record n for h getomp graphics command to capture drawing area GETTRIM h nget a random access record n for h with blanks trimmed GLOBAL creates a global variable go graphics command to move pen GOSUB label call subroutine label goto graphics command to move pen GOTO label branch to label GRAPHICBOX add a graphics region to a window GROUPBOX add a groupbox to a window Graphics window type Graphics Commands a detailed summary of graphics commands in Liberty BASIC HBMP name return the Windows handle for a bitmap HEXDEC value convert a hexadecimal string to a decimal value HIDE make a control invisible HWND handle return the Windows handle for a window home graphics command to center pen IF THEN perform conditional action s Inkey contains a character or keycode from a graphics window INP port get a byte value from an I O port INPUT get data from keyboard file or button INPUT h n get n chars from handle h or from the keyboard INPUTTO h c reads from file up to char specified INPUT purpose parameter in fileopen statement linsert text command to insert text at caret position INSTR a b n search for b in a with optional start n INT n integer portion of n JOY global variables containing joystick information read by readjoystick command Joy1x Joy1y Joy1z Joy1button1 Joy1button2 Joy2x Joy2y
100. Kill BASIC Programs in all system menus true show compile progress false start full screen true make backup of source code when run debug true open with initial file welcome bas initial file to load true use syntax coloring 64 mainwindow columns 24 mainwindow rows false reload more recent file F bak backup pathname true enable compiler reporting bas source file extension 2 externals say how many externals there are Notepad name of first external program notepad exe external program specification Error Log name of second external program notepad exe error log external program specification 1 recent files say how many recent files there are welcome lba first recent file EOF end of file marker The runtime engine will use the default values for editfont printfont and for the mainwin columns and rows Writing your own Programs Once you have loaded Liberty BASIC you can write your own programs Click on the File menu and then New File You see this Liberty BASIC 4 0 untitled _ bas Now type a simple program Press enter and then type this line print Hello World Liberty BASIC untitled bas oik Dielgl ai al sele Alee 3 2 print Hello World Your program runs and looks like this gt Execution of untitled bas complete OF x Hello World FreeForm The Gui Designer FreeForm has been an important part of L
101. LAYWAVE BMPBUTTON Mathematics See also Numeric Variables Mathematical Operations Trigonometry Numbers and Strings Numbers and Numeric Expressions Most mathematical operations in Liberty BASIC can be performed on literal numbers numeric variables or numeric expressions that consist of literal numbers numeric variables or both Functions that require a numeric input can also use any of these forms as long as the expression evaluates to a number Here is the ABS function used as an example print ABS 2 a literal number x 13 print ABS x a numeric variable print ABS 7 233 a literal numeric expression print ABS x 13 a numeric expression containing a variable Arithmetic Arithmetic operators are as follows addition subtraction 8 multiplication division ge power Examples print 2 3 addition print 6 2 subtraction print 4 7 multiplication print 9 3 division print 2 3 power two to the third power print 4 2 6 2 multiple expressions are evaluated according to the following rules of order Order Expressions are evaluated in this order expressions within parentheses are evaluated first A exponents are evaluated next SE multiplication and division are evaluated next addition and subtraction are evaluated last See also SIN COS TAN ASN ACS ATN ABS EXP LOG HEXDEC DECHEX INT MAX MIN RND SQR VAL STR USING Numeric variables In Lib
102. LOG FOR FUNCTION GET GETTRIM GLOBAL GOSUB GOTO GRAPHICBOX GRAPHICS GROUPBOx IF INPUT KILL LET LINE LISTBOX LOADBMP LONG LOOP LPRINT MAINWIN MAPHANDLE MENU NAME NEXT NOMAINWIN NONE NOTICE ON ONCOMERROR OR OPEN OUT OUTPUT PASSWORD PLAYMIDI PLAYWAVE POPUPMENU PRINT PRINTERDIALOG PROMPT PTR PUT RADIOBUTTON RANDOM RANDOMIZE READ READJOYSTICK REDIM REM RESTORE RESUME RETURN RUN SCAN SELECT SHORT SORT STATICTEXT STOP STOPMIDI STRUCT SUB TEXT TEXTBOX TEXTEDITOR THEN TIMER TITLEBAR TRACE ULONG UNLOADBMP UNTIL USHORT VOID WAIT WINDOW WEND WHILE WORD XOR FUNCTIONS Note that the opening parenthisis is part of the function name ABS ACS ASC ASN ATN CHR COS DATE DECHEX EOFT EVAL EVALS EXP HBMP HEXDEC HWND INP INPUT INPUTTO INSTR INT LEFT LEN LOF LOG LOWER MAX MIDIPOS MID MIN MKDIR NOT RIGHT RMDIR RND SIN SPACE SQR STR TAB TAN TIMES TRIM TXCOUNT UPPERS USING VAL WINSTRING WORD VARIABLES BackgroundColor ComboboxColor CommandLine DefaultDir DisplayHeight DisplayWidth Drives Err Err ForegroundColor Joy1x Joy1y Joy1z Joy1button1 Joy1button2 Joy2x Joy2y Joy2z Joy2button1 Joy2button2 ListboxColor Platform PrintCollate PrintCopies PrinterFont PrinterName TextboxColor TexteditorColor Version WindowHeight WindowWidth UpperLeftx UpperLef
103. O CH Zz iw Lo ta oO CH CH EN EH Al Al NN A FORO PRR CH XOR XOR XOR XOR k k OO CH k CO ka ec O k oe See also Bitwise Operations Looping Liberty BASIC provides three constructions for looping One is FOR NEXT another is WHILE WEND and the third is DO LOOP FOR NEXT executes a loop a set number of times which is determined by the starting and ending values in the FOR statement and by the size of the STEP For more on For Next loops click here WHILE WEND executes a loop as long as a specified condition evaluates to TRUE For more on While Wend loops click here DO LOOP provides a loop that always executes once and then only loops back as long as a condition is met For more on DO LOOPs click here WARNING In loops an exit statement is provided for instances where it is necessary to exit the loop before the counter variable has reached its max or the while condition evaluates to false Do not attempt to exit a loop prematurely by issuing a goto statement FOR NEXT The FOR NEXT looping construct provides a way to execute code a specific amount of times A starting and ending value are specified for var 1 to 10 BASIC code next var In this case the BASIC code is executed 10 times with var being 1 the first time 2 the second and on through 10 the tenth time Optionally and usually var is used in some calculation s in the BASIC code For example if the BASIC code i
104. OR x x 5 y y 10 print handle ext backgroundxy x y See how to set up the sprites in Designate Sprites Here is a small program that uses GETBMP to get a background and then scrolls it Notice that no sprites have been added to the program but to update the background a DRAWSPRITES command is issued nomainwin WindowWidth 410 WindowHeight 340 graphicbox w g 0 0 400 300 open Window for window nf as w print w g down fill blue print w g color red backcolor red print w g boxfilled 200 150 print w g getbmp landscape 0 0 399 299 print w g background landscape print w trapclose quit timer 100 scroll wait scroll x x 5 y y 5 print w g backgroundxy x y print w g drawsprites loop wait quit close w end Designate Sprites A sprite bitmap must include a mask above and a sprite below like this The bitmap must be loaded with the LOADBMP command loadbmp smiley smiley bmp NAME The command to add the sprite to the program is ADDSPRITE It designates the NAME to give this sprite and then the name for the sprite bitmap that was given with LOADBMP These names can be the same as in this example print w g addsprite smiley smiley Or the designated sprite NAME can be different from the LOADBMP name Below the bitmap is named smiley when it is loaded and it is given the spritename guy loadbmp smiley smiley bmp print w
105. OTE ABOUT BACKGROUND SIZE The background bitmap image will be stretched to fit the width of the graphicbox if the width is smaller than the width of the graphicbox and the height is stretched if the height of the bitmap is smaller than the height of the graphicbox THESE NUMBERS REFERS TO THE HEIGHT AND WIDTH INDICATED WHEN THE GRAPHICBOX IS CREATED NOT THE VISIBLE PORTION OF THE GRAPHICBOxX It is possible to create a graphicbox whose dimensions are much larger than the window that contains it The background image will be stretched to fit the given dimensions not the visible dimensions of the graphicbox BACKGROUND FROM SCREEN The background may be drawn into the graphicbox or graphics window with Liberty BASIC graphics commands such as FILL LINE BOXFILLED DRAWBMP etc This bitmap is loaded into memory and given a name with the GETBMP command This example uses a graphicbox whose width is 400 and height is 300 The example gets the bitmap from the graphicbox at 0 0 and with a width of 399 pixels and a height of 299 pixels and gives it the name landscape Note that the width and height appear to be less than the width and height of the graphicbox but the graphicbox dimensions include the frame and the background bitmap should only include the inside area It can then be used as the designated background bitmap in the same way as a bitmap loaded with the LOADBMP command print w g getbmp landscape 0 0 399 299 print w g backgrou
106. The fractional part is the part of the number after the decimal point Usage retry input Enter an integer number gt 1 if i lt gt int i then bell print i isn t an integer R Der H goto retry KILL s KILL filename ext Description This command deletes the file specified by filename ext The filename can include a complete path specification LEFT s ni LEFT string number Description This function returns from the string string variable or string expression string the specified number of characters starting from the left If string is hello there and number is 5 then hello is the result Usage retry input Pleas nter a sentence gt sentences if sentenceS then retry for i 1 to len sentence print left sentenceS i next i Produces Please enter a sentence gt That s all folks T Th Tha That That That s That s_ That s a That s al That s all That s al That s all f That s all fo That s all fol That s all folk That s all folks That s all folks Note If number is zero or less then an empty string will be returned If number is greater than or equal to the number of characters in string then string will be returned See also MID and RIGHT LEN s LEN string LEN structName struct Description This function returns the length in characters of string which can be any valid string expression It also returns
107. VAL code Breakpoints for debugging DO LOOP Printerfont Printer Graphics Now Scaled Debugger Improvements ON ERROR GOTO and RESUME ENABLE DISABLE SHOW AND HIDE Groupboxes Accept New Commands PLAYMIDI MIDIPOS STOPMIDI Named Drawing Segments Joystick Support STYLEBITS New Sprite Commands centersprite removesprite spriteoffset spritetravelxy spritetofront spritetoback spriteround Glossary Glossary of General Computer and Programming Terms Alphanumeric Any letter of the alphabet or any digit from 0 to 9 Application A completed program that can be executed the term program is often used Application Programming Interface API A set of definitions of the ways in which one piece of software communicates with another One of the primary purposes of an API is to provide a set of commonly used functions For more see What are APIs ASCII ASCII pronounced as key is short for American Standard Code for Information Interchange It is a standard code that assigns a binary number to all the alphanumeric characters upper and lower case all the symbols on the keyboard and some other symbols not on the keyboard such as the cents symbol It is also known as plain text Associated File A file type that has been identified as belonging to a certain program such as TXT with Notepad BMP with Paint or DOC with Word Binary An alternative number system which works very well for computers It is easiest fora comp
108. Windows program that you can use to explore your disk Expression A combination of variables literals and functions that can be evaluated to a single string or numeric value File A named collection of information stored on a disk A file is a long sequence of bytes which represent data Each file has a name and an extension which are separated by a dot a period The name identifies the file The extension tells the computer what type of data is contained within the file Filename The name assigned to a collection of data that is stored on a disk Filename Extension The optional period and up to three characters at the end of a filename Focus Only one of the items in a window can be accepting input from the keyboard at a time The active item is said to be the item with the focus Folder A folder can be thought of as a location on your hard disk or floppy disk Folders used to be called directories subdirectories A folder contains files and can contain nested folders subfolders Folders and subfolders are used to organize your hard disk Gigabyte Roughly a billion bytes or characters Abbreviated G or GB GUI Graphical User Interface used to describe windows and controls that use pictures to help you interact with the computer Hard Disk A large capacity storage area that offers fast access to information Hardware The physical parts of your computer as opposed to software Highlight To select something by clic
109. X pOmOom AIS 00 D uf Eieiel KEY a Q D ZC II O Bg TEHm Sc e xmy SOXQMON WvS PEKO E Tee ia T BEE TOOM JOM ox AHS PHE MASLA Toen TeX CHL LAG LF PHE SADOM O Ai DEL GG OE Tewsde O ARE SOHSKQem PMOKOma BE z i E az SOM Sevaer Zeche SL e K St Kmo DL SR iM Some Te EE preo T tots BR CO e ox G GxOOM2 Aen Ay ose K S eooxKem FPUSPMPAGF Le BZ eHE2Oe DEL HSO OOOSsm 2 18 eHe2DeP MLK ym K Hat H SIB DD Dep F D I Cik am m mE ZAA ZS
110. a i i it l1 wend close f for j 0 to i print a j next end See also INPUT Input h n INPUTTO h c Listbox First Item Second Item Third Wem Fourth Wem Fifth Wem Seventh litem Eighth Wem H LISTBOX handle ext array eventHandler x y wide high Description Listboxes are added to windows to provide a list selection capability in programs The listbox is loaded with a collection of strings from a specified string array and a RELOAD command updates the contents of the listbox from the array when the contents of the array change handle ext The handle part of this statement must be the same as the handle of the window that contains the listbox The ext part must be unique so that the program can send commands to the listbox and get information from it later array This is the name of the array must be a string array that contains the contents of the listbox Be sure to load the array with strings before opening the window If some time later it is necessary to change the contents of the listbox simply change the contents of the array and send a RELOAD command The index numbers of items in the array may not match the index numbers of the same items in the control The control is loaded from the array and the first index used in the control is 1 No empty strings are loaded into the control so only array items that contain text are loaded eventHandler This is the branch label o
111. a bitmap drawsprites sprite command to update animation Drives special variable holds drive letters DO LOOP performs a looping action until while a condition is met Double data type for CALLDLL DUMP force the LPRINT buffer to print DWORD data type for calldll and structs ellipse graphics command to draw an ellipse ellipsefilled graphics command to draw a filled ellipse ELSE used in block conditional statements with IF THEN ENABLE make a control active END marks end of program execution END FUNCTION signifies the end of a function END IF used in block conditional statements with IF THEN END SELECT signals end of SELECT CASE construct END SUB signifies the end of a subroutine EOF h returns the end of file status for h EVAL code evaluate an expression to a numeric value EVAL code evaluate an expression to a string EXIT FOR terminate a for next logo before itcompletes EXIT WHILE terminate a while wend lcop before itcompletes EXP n returns e n FIELD h list sets random access fields for h FILEDIALOG opens a file selection dialog box FILES returns file and subdirectory info fill graphics command to fill with color font set font as specified FONTDIALOG opens a font selection dialog box ForegroundColor sets or returns foreground color for window FOR NEXT performs looping action FUNCTION define a user function COMMAND REFERENCE A C D F G K L M N P R S T Z Command Reference G
112. a into a variable then fill an array element however wrong read numericArray 1 correct read numl numericArray 1 numl For more see ARRAYS DIM SORT and Sorting Arrays Sorting Arrays Liberty BASIC provides a built in sorting command for arrays Here is an example sort 100 numbers dim numbers 100 for x 0 to 99 numbers x int rnd 1 100 next x sort numbers 0 99 sort items 0 through 99 for x 0 to 99 print numbers x next x end Double dimensioned arrays can also be sorted Todo so it is necessary to add an extra parameter to the command to specify the column sort by the value in column 2 sort numbers 0 99 2 See also SORT Arrays with More than Two Dimensions Although Liberty BASIC only allows arrays with one or two dimensions arrays with three or more dimensions can be easily simulated To simulate an array of 10 by 10 by 10 it is possible to stack the third dimension on top of the second create an array big enough to hold 10x10x10 elements dim myArray 10 100 set a value in the array in 3 dimensions call setMyArray S 5 6 7 Here I am now fetch and print out the value print getMyArrayS 5 6 7 end sub setMyArray x y z value myArray x y z 10 value end sub function getMyArray x y zZ getMyArrayS myArray x y z 10 end function READ and DATA DATA statements can be embedded in Liberty BASIC programs to make access to strin
113. a is appended to the end of the file but does not overwrite data previously written to the file the last time it was opened as open for OUTPUT does Example Program open writ print print writ print print more print print close File Copy test txt for append as 1 some data with line delimiters 1 line one 1 line two some data without line delimiters 1 item three 1 item four data with line delimiters added 1 item five 1 done 1 A file may be copied using sequential file operations The file to be copied is opened for INPUT The file that is to be a copy is then opened for OUTPUT The contents of the original file are retrieved with the INPUT statement and written to the copy with the PRINT statement Both files are then closed Here is an example open mybytes bin for input as original open copybyte bin for output as copy print copy input original lof original close original close copy end Binary Files To access a file in binary mode it must be opened with the OPEN statement When it is no longer needed and before the program ends it must be closed with the CLOSE statement See also Filedialog File Operations Path and Filename In binary access mode bytes are written to the file or read from the file as characters See Chr n Use the SEEK command to seek to the desired point in the file for reading or writing This sets the fi
114. ables literals or both This is accomplished by use of the plus sign varOneS Hello varTwoS World varThreesS varOne varTwoSs print varThrees The program above produces this in the mainwin Hello World It is also possible to use the semi colon to add or concatenate strings varOneS Hello varTwosS World varThreesS varOne varTwoS print varThrees NON PRINTING CHARACTERS Some characters do not display on the screen but instead they format the text output A combination of carriage return and line feed causes text printed after it to display on the next line down These non keyboard characters can be accessed with the CHR n function n is be the ascii value of the desired character In the case of a CRLF as described here the character for carriage return is chr 13 The character for line feed is chr 10 The following code inserts a carriage return forcing the text to print on two lines print Hello chr 13 chr 10 World Produces Hello World PRINTING DOUBLE QUOTATION MARKS The double quotation mark is represented by CHR 34 To cause a double quotation mark to print the character 34 is included like this print chr 34 Hello World chr 34 Produces Hello World GLOBAL In general variables used in the main program code are not visible inside functions and subroutines Variables inside functions and subroutines are not visi
115. above the sprite and together these will be used to draw sprites in Liberty BASIC This is a single bitmap It is possible to add a mask to the sprite image using Paint PaintBrush or any other painting utility but the easiest way to add the mask is to use the Liberty BASIC program provided as part of this help file Add a mask here LAYERING Sprites are displayed by combining the pixels of the background with the pixels of the mask and sprite bitmaps using bitwise operations The programmer does not need to deal with these operations because they are done by Liberty BASIC A Liberty BASIC sprite bitmap contains the mask above the sprite The mask is placed on the background bitmap in memory It is not displayed on the screen in this form The mask is now in place The next layer adds the sprite and results in this picture which is displayed on the screen when a DRAWSPRITES command is issued IMPORTANT To avoid flickering sprite animation is done invisibly in memory When an entire frame of animation is built it is then transferred to the screen IT WILL COVER ANY PREVIOUS GRAPHICS IN THE GRAPHICBOX OR ON THE GRAPHICWINDOW See the section on Drawing and Collision Detection for information about adding graphics to a window with Liberty BASIC graphic commands during sprite animation SPRITES MAY BE PLACED IN ONLY ONE GRAPHICS WINDOW OR GRAPHICBOX IN A PROGRAM Start with the Background WindowHeight 320 WindowWidth
116. ach control statement A control will be colored according to the last color statement listed before the command to create the control Below is a short example WindowWidth 550 WindowHeight 410 TextboxColor red textbox main textboxl 26 16 100 25 TextboxColor S blue textbox main textbox2 30 61 100 25 TextboxColorS yellow textbox main textbox3 30 121 100 25 open untitled for dialog as main main inputLoop wait here for input event wait Here is a list of valid colors in alphabetical order black blue brown buttonface cyan darkblue darkcyan darkgray darkgreen darkpink darkred green lightgray palegray pink red white yellow Palegray and Lightgray are different names for the same color Buttonface is the default background color currently set on a user s system so it will vary according to the desktop color scheme The colornames are not case sensitive so WHITE is the same as white Here is a graphical representation of the available colors yellow brown red darkred pink darkpink blue darkblue green darkgreen cyan darkcyan white WW ack lightgray DO dark gray How to Specify Fonts Font FaceName size attributes In Liberty BASIC there are many places to specify fonts This is done using a font command string containing The font facename The size of the font Optional modifiers italic bold strikeout underscore Here is an example Dra
117. age print The arc tangent of 0 2 is atn 0 2 Tip There are 2 pi radians in a full circle of 360 degrees A formula to convert degrees to radians is radians degrees divided by 57 29577951 Note See also TAN BEEP Description This command will play the default system wave file The actual sound played depends upon the default sound scheme on the user s computer This sound is best described as a ding Program execution will stop until the wave file is finished playing Usage if warningVar 1 then beep Note See also PLAYWAVE PLAYMIDI BMPBUTTON BMPBUTTON handle ext filespec returnVar corner posx posy Description This statement adds a button that displays an image to a window created with the OPEN command Usage The BMPBUTTON statement must be listed before the statement to OPEN the window that will contain it Here is a brief description for each parameter as listed above handle ext The handle must be identical to the handle of the window which will contain the bmpbutton The bmpbutton may have an optional unique extension which allows it to receive commands during program execution The extension begins with a dot and may include any alpha numeric characters A bmpbutton contained on a window whose handle is win will have win as the first part of its handle Examples of bmpbutton handles are as follows win no extension win okay win 1 win cancel win bmpbutton2 filespec T
118. all mergeFiles fileOneS fileTwoS combineds end sub mergeFiles firstFile S secondFile mergeds open merged for output as merged open firstFileS for input as first print merged inputS first lof first close first open secondFile for input as second print merged inputS second lof second close second close merged end sub See also FUNCTION Recursion Functions and Subroutines TAB n Print TAB n Liberty BASIC 4 has the ability to use the TAB function for formatting output to the mainwin and to the printer n is the character location where the next output will be printed tab 7 causes the next output to print beginning at column character 7 while tab 21 causes the next output to print beginning at column 21 TAB n works with both the mainwin PRINT command and with LPRINT show how tab works print x tab 7 sine tab 21 cosine for x 1 to 10 print x tab 7 sin x tab 21 cos x next x end TAN n Description This function returns the tangent of the angle n The angle n should be expressed in radians Usage for t 1 to 45 print The tangent of t is tan t next t Tip There are 2 pi radians in a full circle of 360 degrees A formula to convert degrees to radians is radians degrees divided by 57 29577951 Note See also GIN and COS Textbox Text ox TEXTBOX handle ext xpos ypos wide high Description The textbox command adds
119. and Subroutines Function Sub Branch Labels Liberty BASIC will accept numbers as branch labels This is useful when using old BASIC code The numbers don t change the order of the code The following two short programs are essentially the same 10 REM count to ten 20 for x 1 to 10 30 print x 40 next x 50 end 20 REM count to ten 40 for x 1 to 10 10 print x 30 next x 50 end Instead of using numeric branch labels it is better to use alphanumeric ones because they are descriptive and help the programmer remember what is happening in a block of code In Liberty BASIC alphanumeric branch labels are surrounded by square braces myBranchLabel Spaces and numbers are not allowed as part of branch label names and names may not start with a numeral Here are some valid branch labels mainMenu enterLimits repeatHere Here are some invalid branch labels enter limits mainMenu 1moreTime In QBASIC branch labels end with a colon and looks like this myBranchLabel The above program doesn t really need branch labels It looks like this without them count to ten for x 1 to 10 print x next x end A program to count without a for next loop looks like this count to ten startLoop X xdti1 print x if x lt 10 then startLoop end Just for comparison in QBASIC it looks like this count to ten startLoop x x 1 print x if x lt 10 then goto startLoop end NOTE Branch labels inside functi
120. and circles may be drawn and they may be either filled with an opaque color or they may be drawn as an outline only Drawn Text Graphics commands include the ability to place text on the graphics control at the location desired Color and Size The size width of the drawing pen may be set The color that covers the control may be set as well as the outline color of drawn objects and the color that fills drawn objects Drawing Segments and FLUSH Drawing happens in segments Drawing operations are queued up into the current drawing segment A FLUSH command closes the current segment and opens a new one The segments which have been closed will be used to redraw the drawn graphics when the window needs to be repainted Any drawing that does not exist in a closed segment will not be redrawn when the window is repainted FLUSH Drawing commands can be made to persist or stick when the FLUSH command is used graphicbox w g 5 5 250 250 open I m a window for window as w print w g home down print w g fill green print w g circle 100 print w g flush wait Deleting Drawing Segments Ifa graphics window or graphicbox has received many drawing commands it is advisable to delete unwanted segments If drawing segments are not deleted the computer s RAM will eventually fill with drawing commands There are two ways to delete these unwanted drawing commands CLS The simplest way to delete drawing commands is
121. and no items Do not include the A character in this dummy edit menu title If the location for the automatic edit menu is not specified it will appear at the right end of the menu bar Example locate the edit menu in the second position on the menu bar menu 1 amp File E amp xit quit menu 1 edit menu 1 amp Help amp About about See also POPUPMENU MID MID string index number Description This function permits the extraction of a sequence of characters from the string string variable or string expression string starting at index number is optional If number is not specified then all the characters from index to the end of the string are returned If number is specified then only as many characters as number specifies will be returned starting from index Usage print mid greeting Earth creature 10 5 Produces Earth And stringS The quick brown fox jumped over the lazy dog for i 1 to len string S step 5 print midS string i 5 next i Produces The_q uick_ brown _fox_ jumpe_ d_ove r_the _lazy _dog Note See also LEFT and RIGHTS MIDIPOS var MIDIPOS Description This function returns the current position of play in a file being played with PLAYMIDI See also PLAYMIDI STOPMIDI MIN MIN expr expr2 Description This function returns the smaller of two numeric values Usage input Enter a number a
122. and the numeric version of the function converts it to numeric values Evaluating to a string Here we show how to evaluate code to a string and what happens if you try to evaluate it to be a number Let s evaluate some code that produces a non numeric result a 0 zero a 1 one a 2 two code aS int str rnd 1 3 print We will evaluate the code code resultS evalS code print results Now let s use the eval function which effectively does a val to the result of the calculation Converting a non numeric string to a numeric value results in zero result eval code print result Evaluating to a number Here s an example of the most common type of code evaluation users will want to do Numeric computation Let s just make a short example that asks you to type an expression to evaluate ask for an expression input Type a numeric expression gt codeS answer eval code print answer Date and Time Functions Liberty BASIC provides several ways to retrieve date and time information Date and Time are functions that return values that can be used in mathematical operations See also Date and Time Date This form of date produces this format print date Nov 30 1999 print dateS mm dd yyyy 11 30 1999 print dateS mm dd yy 11 30 99 print dateS yyyy mm dd 1999 11 30 for sorting print dateS days 36127 days since Jan 1 19
123. as measured in pixels in x and y from the upper left corner of the window width amp height These specify the width and height of the textbox in pixels It should be noted that graphics windows and graphicboxes are intended for drawing graphics It is not advisable to place controls within them since some controls do not work properly when placed in graphicboxes or graphics windows If there is a need for text display within a graphicbox or graphics window use the graphics text capabilities rather than a statictext control Jump to commands for graphics commands GRAPHICBOX COMMANDS The following commands are sent to a graphicbox When a graphicbox is disabled it can no longer capture keyboard and mouse events print handle ext setfocus This causes the control to receive the input focus This means that any keypresses will be directed to the control print handle ext enable This causes the control to be enabled print handle ext disable This causes the control to be inactive It can no longer capture mouse and keyboard events print handle ext show This causes the control to be visible print handle ext hide This causes the control to be hidden or invisible GROUPBOX GroupBox M CheckBox RadioButton C RadioButton 2 GROUPBOX handle ext label x y wide high Description This command adds a groupbox to a window or dialog box Other controls added to the owning window which over
124. at was used by the drawn segment is reclaimed by the operating system When the window is redrawn the deleted segment will not be included in the redraw See the SEGMENT command for instructions on retrieving a segment ID number print handle delsegment segmentName This causes the drawn segment that has been assigned segmentName to be removed from the window s list of drawn items The memory that was used by the drawn segment is reclaimed by the operating system When the window is redrawn the deleted segment will not be included in the redraw See the FLUSH command for instructions on assigning segment names print handle discard This causes all drawn items since the last flush to be discarded this also reclaims memory used by the discarded drawn items Discard does not force an immediate redraw so the items that have been discarded will still be displayed until a redraw see redraw print handle down This command is the opposite of UP This command reactivates the drawing process The pen must be DOWN to cause graphics to be displayed print handle drawbmp bmpname x y This command draws a bitmap named bmpname loaded beforehand with the LOADBMP statement see command reference at the location x y print handle ellipse w h This command draws an ellipse centered at the pen position of width w and height h print handle ellipsefilled w h This command draws an ellipse centered at the pen position of width w and h
125. atement reads data up to a specified delimiter Here is an illustration of the differences between the various forms of INPUT statements Example Program create a sample file open test txt for output as 1 print 1 123 Sesame Street New York NY close 1 INPUT open test txt for input as 1 INPUT 1 txt print INPUT item is txts close 1 LINE INPUT open test txt for input as 1 LINE INPUT 1 txt print LINE INPUT item is txt close 1 INPUTS open test txt for input as 1 txtS INPUTS 1 10 read 10 characters print INPUTS item is txt close 1 INPUTTOS S open test txt for input as 1 txtS INPUTTOS 1 use a blank space as delimiter print INPUTTOS item is txts close 1 Produces INPUT item is 123 Sesame Street LINE INPUT item is 123 Sesame Street New York NY INPUTS item is 123 Sesame INPUTTOS item is 123 INPUT Multiple Items Here is a short program which opens a text file and reads a line at a time printing each line to the mainwin filedialog Open txt files if file then end open file for input as 1 while eof 1 0 line input 1 text print texts wend close 1 print a notice that the end of file is reached print print print EOF OUTPUT Files opened for OUTPUT can be written to sequentially If a file opened for OUTPUT does not exist it will be created Ifthe file does exist on di
126. ation to a Windows 95 98 ME system you should install ntport dll to your client s Windows System directory You need not distribute the zntport sys For Windows NT 2000 XP When you install your application to a Windows NT 2000 XP system you have two choices 1 If all the users have administrative rights which is usually the case unless someone in your IT department has not given you administrative rights you can install ntport dll and zntport sys to your client s WinNT System32 directory In this case you need not do any other configuration 2 If some users don t have administrative rights you need to create an installation program to install the NTPort Library driver The installation program should do following steps Install ntport dll to WinNT System32 directory Install zntport sys to WinNT System32 drivers directory Import the registry settings from ntport2 reg this file is in the ntport directory Restart Windows In this case you still need administrative rights to run the installation program but after the reboot any normal user can use your program Making API and DLL Calls Liberty BASIC can make 32 bit Windows API calls and also bind to third party Dynamic Link Libraries Liberty BASIC programmers now have access to hundreds of functions provided in Windows and from third party sources that can greatly increase productivity Calling APIs and DLLs Informational resources about APIs DLLs What are APIs DLLs
127. awing overwrites rulename OVER graphics already on the screen or uses the exclusive OR technique rulename XOR It is also possible to use Windows constants to select a drawing rule as shown above Here are the constants that Windows defines _R2_BLACK _R2_WHITE _R2_NOP _R2_NOT _R2_COPYPEN lt the default LB drawing rule _R2_NOTCOPYPEN _R2_MERGEPENNOT _R2_MASKPENNOT _R2_MERGENOTPEN _R2_MASKNOTPEN _R2_MERGEPEN _R2_NOTMERGEPEN _R2_MASKPEN _R2_NOTMASKPEN _R2_XORPEN _R2_NOTXORPEN lt the xor LB drawing rule print handle segment variableName This causes the window to set variableName to the segment ID of the currently open drawing segment To get the segment ID of the last segment flushed subtract one Segment ID numbers are useful for manipulating different parts of a drawing print handle set x y This command draws a point at x y using the current pen color and size print handle setfocus This causes Windows to give input focus to this control This means thst ifsome other control in the same window was highlighted and active this omtrol now becomes the highlighted and active control receiving mouse and keyboard input print handle size S This command sets the size of the pen to S The default is 1 This will affect the thickness of lines and figures plotted with most of the commands listed in this section print handle stringwidth varToMeasure widthInPixels This command retrieves
128. begins with a valid numeric value If not then zero is returned Usage print 2 val 3 14 Produces 6 28 print val hello Produces 0 print val 3 blind mice Produces 3 STR numericExpression Description This function returns a string expressing the result of numericExpression Usage age 23 ageS str age price 2 99 prices str price totalApples 37 print Total number of apples is str totalApples USING templateString numericExpression Description This function formats numericExpression as a string using templateString The rules for the format are similar to those in Microsoft BASIC s PRINT USING statement but since using is a function it can be used as part of a larger BASIC expression instead of immediate output only The template string consists of the character to indicate placement for numerals and a single dot to indicate placement for the decimal point The template string must be contained within double quotation marks If there are more digits contained in a number than allowed for by the template string the digits will be truncated to match the template A template string looks like this amountS using H t 1234 56 As part of a larger expression notice Your total is using 1234 5 A template string can be expressed as a string variable templateS Ain amountS using templateS 1234 56 Using may be used in
129. begins with a valid numeric value If not then zero is returned Usage print 2 val 3 14 Produces 6 28 print val hello Produces 0 print val 3 blind mice Produces 3 Version Version Description This variable holds the version of Liberty BASIC in this case 4 0 This is useful so that you can take advantage of whatever differences there are between the different versions of Liberty BASIC Note see also Platform WAIT Description This simple statement causes program execution to stop and wait for user input events When the user interacts with a window or other control owned by the program and generates an event program execution resumes at the event handler appropriate for their interaction Usage demonstrate the wait command in three places nomainwin open Geometric wite board for graphics nsb as geo print geo trapclose quit print geo when rightButtonUp popupMenu wait stop and wait for a menu item to be chosen popupMenu popupmenu amp Square Spiral asSquare amp Triangular Spiral asTriangle wait asSquare print geo cls home down color red for x 1 to 120 print geo go x turn 87 next x wait asTriangle print geo cls home down color blue for x 1 to 120 print geo go x turn 117 next x wait quit close geo end Note In general Liberty BASIC encourages the use of wait over the previous pra
130. ble in the main program Liberty BASIC 4 introduces the GLOBAL statement to create global variables Variables declared as GLOBAL can be seen everywhere in a program See GLOBAL The special system variables like WindowWidth WindowHeight etc now have true global status GLOBALS are specified and used like this global filename authors title filenames readme txt authorS John Q Programmer title Great Idea Manipulating Characters CHR n Description This function returns a one character long string consisting of the character represented on the ASCII table by the value n 0 255 Usage print chr 77 print chr 34 print chrs 155 Produces M H INSTR string1 string2 starting Description This function returns the position of string2 within string1 If string2 occurs more than once in string1 then only the position of the leftmost occurance will be returned Ifthe starting parameter is included then the search for string2 will begin at the position specified by starting Usage print instr hello there lo produces 4 print instr greetings and meetings eetin produces 3 print instr greetings and meetings eetin 5 produces 16 If string2 is not found in string1 or if string2 is not found after starting then INSTR will return 0 print instr hello el 3 produces 0 and so does print instr hello bye LEN string Descriptio
131. bled print handle ext disable This causes the control to be inactive and grayed out print handle ext show This causes the control to be visible print handle ext hide This causes the control to be hidden or invisible See also Text Commands For information on creating controls with different background colors see Colors and the Graphical User Interface TIMES Description This function returns a string representing the current time of the system clock in 24 hour format This function replaces the time variable used in QBasic See also DATES Date and Time Functions ERIS print print print print Usage form of time produces this format time time now as string 16 21 44 times seconds seconds since midnight as number 32314 timeS milliseconds milliseconds since midnight as number 33221342 times ms milliseconds since midnight as number 33221342 display the opening screen print We Main selection screen Time now times print print print 1 Add new record 2 Modify existing record print 3 Delete record TIMER TIMER milliseconds branchLabel Timer milliseconds subName Description This commands manages a Windows timer This is useful for controlling the rate of software execution games or animation perhaps or for creating a program or program feature which activates periodically a clock perhaps or an email client which checks
132. bmp blank4 bmp button1lClick UL 22 11 bmpbutton main button2 bmp blank4 bmp button2Click UL 22 46 open BmpButton Image Changer for window as main print main trapclose quit wait here for user events wait button1lClick Display arrow image on button 2 print main button2 setfocus print main button2 bitmap arrow print main buttonl bitmap blue wait button2Click Display arrow image on button 1 print main buttonl setfocus print main buttonl bitmap arrow print main button2 bitmap blue wait quit close main end print handle ext locate x y width height This command repositions the control in its window This is effective when the control is placed inside a window of type window The control will not update its size and location until a REFRESH command is sent to the window See RESIZER BAS for an example program print handle ext setfocus This causes the control to receive the input focus This means that any keypresses will be directed to the control print handle ext enable This causes the control to be enabled print handle ext disable This causes the control to be inactive and grayed out print handle ext show This causes the control to be visible print handle ext hide This causes the control to be hidden or invisible See also BUTTON MENU Controls and Events BMPSAVE bmpsave bmpName filename bmp Description T
133. call setHorizSpeed 8 call setVertSpeed 0 call gravityAccelerate timer 100 timerTicked startTime time milliseconds wait timerTicked This is the main simulation routine frames frames 1 if altitude lt terrain longitude 15 24 then call setAttitude attitude call applyThrust thrust attitude call gravityAccelerate altitude altitude getVertSpeed longitude max 0 min 485 longitude getHorizSpeed print lander spritexy lem longitude print lander drawsprites else timer 0 if landerCrashed longitude attitude then notice You crashed else notice Successful landing end if confirm Try again answer if answer then startGame else quit end if wait quit close lander end userInput charS Inkeys if chars then attitude attitude 22 5 if attitude lt 0 01 then attitude 337 5 wait end if if char then attitude attitude 22 5 if attitude gt 337 51 then attitude 0 wait end if thrustInput instr 0123456789 charS if thrustInput then thrust thrustInput 1 8 0 55 0 333 wait function landerCrashed xPosition attitude landerCrashed int attitudet 0 1 lt gt 90 landerCrashed landerCrashed or getVertSpeed gt 2 landerCrashed landerCrashed or getHorizSpeed gt 2 landerCrashed landerCrashed or terrain xPosition lt gt terrain xPositi
134. cancelSearch if len response 2 and instr A B C responseS gt 0 then search responseS C prompt Unacceptable response Please try again A B or C response goto testResponse search print Starting search Specify a Caption responseS C prompt Please Specify chr 13 Search on which Drive Ar B or C responses PUT h n PUT handle n Description PUT is used after a random access file is opened to place a record of information see FIELD into the file handle at the record numbered n For example open a random access file open custdata 001 for random as cust len 70 field cust 20 as nameS 20 as street 15 as city _ 2 as state 10 as zipS 3 as age enter data into customer variables input nameS put the data into record 1 put cust 1 close cust end Note See also GET FIELD Random Files RADIOBUTTON RadioButton RADIOBUTTON handle ext label setHandler resetHandler x y wide high Description This command adds a radiobutton control to the window referenced by handle Radiobuttons have two states set and reset They are useful for getting input of on off type information All radiobuttons on a given window are linked together so that if one is set by clicking on it all the others will be reset cleared The exception to this rule occurs when radiobuttons are placed within the confines of groupboxes In this case only radiobuttons co
135. ce of the Windows API set is not included with this copy of Liberty BASIC To supply this documentation would require the inclusion of a very thick book Some example programs are included with the Liberty BASIC distribution What are DLLs DLL stands for Dynamic Link Library A DLL is a file containing executable code like an EXE or COM file Instead of containing a complete program a DLL contains functions that can be used by other programs These functions might contain code to provide services not built into Windows for example the ability to perform some kind of data compression A Windows program uses these functions after it begins executing It does this by opening the DLL file and calling functions from it The programmer must already know what these functions are when the program s code is written Each DLL has its own Application Programming Interface again API that specifies how to make calls to its functions and in fact Windows APIs are functions within DLLs that are supplied with Windows When calling an API from within Liberty BASIC it is necessary to open the appropriate DLL before making the call See also CALLDLL STRUCT Using Types with CALLDLL How to make API DLL calls Since making an API call is really the same as making a DLL call the following applies to both In general calling an API DLL function works 1 Open the desired DLL 2 Call the function or functions 3 Close the DLL The desired DLL s can be
136. ch to begin the sort and the end parameter specifies the element where sorting should stop Arrays can be sorted in part or in whole and with double dimensioned arrays the specific column to sort by can be declared When this option is used all the rows are sorted against each other according to the items in the specified column Usage Here is the syntax for the sort command sort arrayName i j n This sorts the array named arrayNameS starting with element i and ending with element j If it is a double dimensioned array then the column parameter tells which nth element to use as a sort key Each WHOLE row moves with its corresponding key as it moves during the sort If you have a double dimensioned array holding sales rep activity repActivity x y It can be holding data one record per x position and the record keys are in y So for example repActivity 1 1 Tom Maloney repActivity 1 2 01 09 93 repActivity 2 1 Mary Burns repActivity 2 2 01 10 93 repActivity 100 1 Ed Dole repActivity 100 2 01 08 93 To sort the whole 100 items by the date field this is how the command would look sort repActivity 1 100 2 To sort by name instead then change the 2 to a 1 like this sort repActivity 1 100 1 Sort Reversed Reverse the order of the sort by reversing the order of the range of rows to sort sort from row 1 to 50 sort array 1 50 sort reversed from row 1 to 50
137. cify enough width and height to accomodate the text in string Statictext Commands print handle ext a string This changes the text displayed on a statictext control This command sets the contents the visible label of the statictext to be a string The handle must be of form handle ext that includes a unique extension so that commands can be printed to the control print handle ext locate x y width height This repositions the statictext control in its window This only works if the control is placed inside window of type window The control will not update its size and location until a REFRESH command is sent to the window See the RESIZE BAS example program print handle ext font facename pointSize This sets the control s font to the specified face and point size If an exact match cannot be found then Liberty BASIC will try to find a close match with size taking precedence over face For more on specifying fonts read How to Specify Fonts Example print handle ext font times new roman 10 print handle ext enable This causes the control to be enabled print handle ext disable This causes the control to be inactive and grayed out print handle ext show This causes the control to be visible print handle ext hide This causes the control to be hidden or invisible Sample Program sample program statictext member Name 10 10 40 18 statictext member Address 10 40 70
138. colors of certain windows and controls These variables are case sensitive and must be typed in the proper case For example backgroundcolor is not the same as BackgroundColor The following code creates a window with a dark blue background and light gray text It does this by setting the BackgroundColor and ForegroundColor variables BEFORE OPENING THE WINDOW set the foreground and background colors BackgroundColors darkblue ForegroundColor lightgray statictext dialog static What is your name 10 10 100 20 textbox dialog tbox 10 30 100 20 button dialog accept Accept gotIt UL 10 55 open Name getter for dialog as dialog print dialog tbox Type your names in here print dialog trapclose quit wait gotIt print dialog tbox contents name notice Hi names wait quit close dialog end Setting BackgroundColor sets the color of the background of the window and of groupboxes checkboxes radiobuttons and statictext controls Setting the ForegroundColor sets the color of text displayed in all controls Only the last ForegroundColor and BackgroundColor values set before a window is opened are valid for that window Other special color variables exist for setting the background color of several widgets TextboxColor ComboboxColor ListboxColor TexteditorColor The value of the TextboxColor TexteditorColor ListboxColor or ComboboxColor variable can be changed in between e
139. command to clear texteditor color graphics command to set pen color COLORDIALOG activates the windows common color dialog COMBOBOX add a combobox to a window ComboboxColor sets or returns combobox color CommandLine contains any command line switches used on startup CONFIRM opens a confirm dialog box Icontents text command to replace contents of texteditor Icontents text command returns contents of texteditor Icopy text command to copy text to clipboard COS n cosine ofn CURSOR changes the mouse cursor Icut text command to cut text and copy to clipboard cyclesprite sprite command to cause animation to cycle COMMAND REFERENCE A C D F G K L M N P R S T Z Command Reference D F Commands and Keywords A C D F G K L M N P R S T Z DATA adds data to a program that can be read with the READ statement DATE return string with today s date DECHEX return a decimal number converted to a hexadecimal string DefaultDir a variable containing the default directory delsegment graphics command to delete drawing segment Dialog window type DIM array set the maximum size of a data array DISABLE make a control disabled and grayed out discard graphics command to discard unflushed drawing DisplayWidth a variable containing the width of the display DisplayHeight a variable containing the height of the display DLL device open mode for calldll down graphics command to lower pen drawbmp graphics command to display
140. corner If the window size is changed during execution of the program the button will always appear at the same position relative to the corner specified as the anchor UL upper left UR upper right LL lower left LR lower right posx posy These parameters set the location for the button relative to the anchor corner posx and posy are expressed in pixels Anchor values of less than one may also be used for posx and posy For example if the anchor corner is UL posx is 9 and posy is 9 then the button will be positioned 9 10ths of the distance of the window in both x and y from the upper left corner This method of positioning buttons places them in positions that are relative to the size of the window rather than anchoring them to a specified corner Images for Bmpbuttons A collection of button images has been included with Liberty BASIC in the folder named bmp The collection includes blank buttons A drawing program such as MS Paint can be used to edit and create button images for Liberty BASIC Detecting Button Presses Button presses are read and acted upon when a SCAN statement is issued If SCAN is not used then program execution must be halted at an INPUT or WAIT statement in order for a button press to be read and acted upon SAMPLE PROGRAMS An example that uses a branch label button handler bmpbutton main arrow bmp arrwbttn bmp arrowClicked UL 10 10 open Button Example for window as main
141. ct match cannot be found then Liberty BASIC will try to find a close match with size taking precedence over face For more on specifying fonts read How to Specify Fonts Example print handle ext font times new roman 10 print handle ext enable This causes the control to be enabled print handle ext disable This causes the control to be inactive and grayed out print handle ext show This causes the control to be visible print handle ext hide This causes the control to be hidden or invisible For information on creating controls with different background colors see Colors and the Graphical User Interface Usage Here are sample programs that use checkboxes This code demonstrates how to use checkboxes in Liberty BASIC programs with branch label handlers nomainwin button 1 amp Ok quit UL 120 90 40 25 checkbox 1 cb I am a checkbox set reset 10 10 130 20 button 1 Set set UL 10 50 button 1 Reset reset UL 50 50 textbox 1 text 10 90 100 24 WindowWidth 180 WindowHeight 160 open Checkbox test for dialog as 1 print 1 trapclose quit inputLoop input r set print 1 cb set goto readCb reset print 1 cb reset goto readCcb end readCb print 1 cb value input 1 cb t print 1 text I am t goto inputLoop quit close 1 end This code demonstrates how to use checkboxes in Liber
142. cterInput trapclose quit loopHere make sure graph has input focus print graph setfocus scan for events scan goto loopHere keyPressed key InkeyS if len key lt 2 then print pressed keyS else print Unhandled special key end if goto loopHere quit print Quitting close graph end InkeyS example for graphics as graph keyPressed Using virtual key constants with Inkey Keyboard input can only be trapped in graphics windows or graphicboxes When a key is pressed the information is stored in the variable Inkey To check for keypresses send the command when characterlnput branchLabel to the graphics window or graphicbox and evaluate Inkey at the designated branch label Special keys like Alt Ctrl Shift the Arrow keys etc are not coded like the letters numbers and other symbols They have special values and are preceded by a value of 32 or less when they are trapped by Inkey Windows has values defined for these special keys which are expressed in virtual key constants You can use these constants and other special Windows constants in your Liberty BASIC programs See also Graphics Commands Inkey Reading Mouse and Keyboard Input and Using Inkey See Inkey for a discussion of the meaning of the first character of Inkey when it is longer than one character Key Up and Key Down Special keys trigger a new value for Inkey when they are pressed and again when the
143. ctice of using input WHILE EXIT WHILE WEND WHILE expression some code WEND Description These two statements comprise the start and end of a control loop Between the WHILE and WEND code is placed optionally that is executed repeatedly while expression evaluates to true The code between any WHILE statement and its associated WEND statement will not execute even once if the WHILE expression initially evaluates to false Once execution reaches the WEND statement for as long as the WHILE expression evaluates to true then execution will jump back to the WHILE statement Expression can be a boolean numeric or string expression or combination of expressions Usage loop until midnight go read a good book while timeS lt gt 00 00 00 some action performing code might be placed her wend Or loop until a valid response is solicited while val age 0 input How old are you ageS if val age 0 then print Invalid response Try again wend Note A program SHOULD NOT exit a WHILE WEND loop using GOTO It may cause the program to behave unpredictably See EXIT WHILE below GOSUB FUNCTION and SUB may be used within a WHILE WEND loop because they only temporarily redirect program flow or call on other parts of the program Program execution resumes within the WHILE WEND loop in these instances Program execution does not return to the WHILE WEND loop if GOTO is used within the loop GOTO should n
144. ction texteditor win te 10 10 250 250 open Enum Windows Example for window as win print win trapclose quit set the variable named address to be the memory address for enumWndProc using TYPES handle and ulong and set the return TYPE of enumWndProc to be a boolean callback address enumWndProc handle ulong boolean call EnumWindows which in turn calls back into the BASIC function at address calldll user32 EnumWindows address as ulong 0 as long _ result as boolean wait quit close win end function enumWndProc hwnd lparam labelBufferS space 71 calldll user32 GetWindowTextA hwnd as ulong _ labelBufferS as ptr 70 as long result as long if left labelBuffer 1 lt gt chr 0 then print win te labelBuffers call setCount getCount 1 end if if getCount 5 then enumWndProc 0 returning 0 causes else enumWndProc 1 end if end function sub setCount value count 0 value end sub function getCount getCount count 0 end function EnumWindows to return CALLDLL CALLDLL handle function param as type param2 as type2 return as returnType Description CALLDLL is used to call functions from the Windows API or from a third party DLL A DLLis a Dynamic Link Library which is a module containing functions that can be called by a program while it is running The functions are specific to the DLL The
145. ctive control receiving keyboard input print handle trapclose branchLabel This command tells Liberty BASIC to continue execution of the program at branchLabel if the user double clicks on the system menu box or pulls down the system menu and selects close Graphics See also graphics commands Liberty BASIC supports drawing operations There are two kinds of controls that accept drawing commands one is a kind of window and the other is a control called a graphicbox They both support the same drawing operations Here is an example of a graphics window open I m a graphics window for graphics as g print g home down print 9 fill green print 9 circle 100 wait And here s the same drawing operation in a graphicbox which has been inserted into a window graphicbox w g 5 5 250 250 open I m a window for window as w print w g home down print w g fill green print w g circle 100 wait The graphics operations are performed by a pen The pen can be up or down Ifthe penis up the drawing operations will not appear The pen moves but does not draw The pen defaults to the up position Possible drawing operations include Turtle Graphics Turtle graphics are drawn by a pen that moves about the screen from one location to another drawing if is in the DOWN position Turtle graphics are good for drawing graphics and iterative objects Drawn Objects Objects such as boxes lines
146. cuting the code as long as the booleanExpr evaluates to true Here is the routine that counts to 10 using DO LOOP with while and DO LOOP with until count to 10 using loop while and loop until do print a a a 1 loop while a lt 11 print do print b b b 1 loop until b 11 For more on DO LOOPs click here Recursion Liberty BASIC supports recursive subroutine and function calls This means that a function can call itself When it does this it makes a copy of itself reusing its variable names The values are not overwritten It is important to place an evaluation statement inside a recursive function that causes the function to finish and return to the main code Care should be taken to avoid creating an endlessly looping recursive function The two examples below contains an IF THEN evaluation that when met causes the function to stop calling itself and return control to the main program Here is an example of a subroutine which counts down from a number countdown print Let s count down from three call countDown 3 end sub countDown number print number if number gt 1 then call countDown number 1 end sub Now here s an example of a recursive function that returns the factorial of a number A factorial is obtained by taking a number and multiplying it in turn by each integer less than itself The factorial of 5 is 5x4x3x2x1 120 The factorial of 7 is 7x6x5x4x3x2x1 5040 The numbers get big in a hurry af
147. d empty string respectively functionName returnValueExpression Local Variables The variable names inside a function are scoped locally meaning that the value of any variable inside a function is different from the value of a variable of the same name outside the function Passing by Reference Variables passed as arguments into functions are passed by value which means that a copy of the variable is passed into the function The value of the variable is not changed in the main program if it is changed in the function A variable may instead by passed byref which means that a reference to the actual variable is passed and a change in the value of this variable in the function changes the value of the variable in the main program Global Variables and Devices Variables declared with the GLOBAL statement are available in the main program and in subroutines and functions Arrays structs and handles of files DLLs and windows are global to a Liberty BASIC program and visible inside a function without needing to be passed in Special global status is given to certain default variables used for sizing positioning and coloring windows and controls These include variables WindowWidth WindowHeight UpperLeftx UpperLeftY ForegroundColor BackgroundColor ListboxColor TextboxColor ComboboxColor TexteditorColor The value of these variables as well as DefaultDir and com can be seen and modified in any subroutine function B
148. d as an event handler or a subroutine may be specified as an event handler A program may use either subroutines or branchlabels or a combination as event handers Both ways are discussed below Branch Label Event Handlers button main accept Accept userAccepts UL 10 10 This adds a button to the window main labeled Accept When the program is run and the user clicks on this button then execution branches to the event handler routine at the label userAccepts When the user clicks on the button it generates an event This is generally how branch label arguments are used in Liberty BASIC windows and controls Liberty BASIC can only respond to events when execution is halted at in INPUT or WAIT statement or when a SCAN command is issued Here is a short program This code demonstrates how to use checkboxes in Liberty BASIC programs nomainwin button 1 amp Ok quit UL 120 90 checkbox 1 cb I am a checkbox set reset 10 10 130 20 button 1 Set setCheckBox UL 10 50 40 25 button 1 Reset resetCheckBox UL 60 50 50 25 textbox 1 text 10 90 100 24 WindowWidth 190 WindowHeight 160 open Checkbox test for dialog as 1 print 1 trapclose quit wait here for user actions wait setCheckBox print El cb set set print 1 cb value ts print El Gest I am t wait resetCheckBox print 1 cb reset reset print 1 cb value ts pr
149. d as the acronym GUI It refers to a window and all of its controls These are the graphical elements that interact with the user The user may click a button or type into a textbox for instance The possible TYPES of windows available in Liberty BASIC programs are listed in Window Types The commands that can be sent to windows are listed in Window and Dialog Commands See also Size and Placement of Windows and Trapping the Close Event The controls available for placement on windows are listed in Controls Menus Buttons etc Information about handling user generated events is given in Controls and Events Coloring of windows and controls is discussed in Colors and the Graphical User Interface An explanation of the methods for sending commands is discussed in Understanding Syntax as well as in Sending Commands Changing the handle of a window dynamically at runtime can be accomplished with the MAPHANDLE command Here is an image of a window that contains many controls Window Title OF EX Menu Title Edit GroupBox First Wem Second Item Third Item Fourth em Fifth Item MV CheckBox RadioButton C RadioButton 2 Seventh Hem Eighth Item x Texth ox Static Text Combobox Button Liberty BASIC leverages the familiar statements OPEN CLOSE PRINT and optionally INPUT for working with graphical user interface elements For example open My Text Window for text as txtWin pr
150. d button If you are having trouble debugging code at a certain spot then you can add a TRACE statement usually level 2 just before that location run in Debug mode and then click on the RUN button in the debugger When the TRACE statement is reached the debugger will kick in at that point slowing the debugging process to STEP mode Usage open wave for graphics as graph print graph down for index 1 to 200 if index 20 then trace 2 Here is the trouble spot print graph goto index 100 int 100 sin index 20 next index wait TRIM s TRIM stringExpression Description This function removes any spaces from the start and end of the string in stringExpression This can be useful for cleaning up data entry among other things Usage sentenceS Greetings print len trimS sentence Produces 9 TXCOUNT txcount handle Description This function gets a count of bytes in a serial communications transmit queue count txcount com See also Open Comn ONCOMERROR UNLOADBMP UNLOADBMP name Description This command removes from Liberty BASIC the bitmap specified by name It also frees the Windows memory resources associated with that bitmap This is useful for freeing bitmap resources when many bitmaps are used in a program Unload all bitmaps loaded with LOADBMP when a program closes to insure that system resources are freed See also LOADBMP HBMP UPPER s
151. d for the handle It must start with a and may contain any alpha numeric characters but no spaces This special handle is used to identify the open device in later program statements Some possible handles are as follows commHandle newfile main win gdi32 2 Changing the handle of a device dynamically at runtime can be accomplished with the MAPHANDLE command OPEN COMn OPEN COMnh baud parity data stop options for random as handle Description The OPEN COMnh statement opens a serial communications port for reading and writing This feature uses Microsoft Windows own built in communications API so if you have a multiport communications card and a Windows driver to support that card you should be able to use any port on the card The simplest form for this command is OPEN COMn baud parity data stop for random as handle Allowable choices for baud are 75 110 150 300 600 1200 2400 1800 2400 4800 9600 19200 38400 57600 115200 Allowable choices are parity are N No parity E Even parity O Odd parity S Space parity M Mark parity Allowable choices for data are 5 bits long 6 bits long 7 bits long 8 bits long Allowable choices for stop are 1 stop bit 2 stop bits Additional optional parameters can be included after the baud parity data and stop information CSn Set CTS timeout in milliseconds default 1000 milliseconds DSn Set DSR timeout in milliseconds default 1000 milliseconds PE
152. d with the default extension is the default button CURSOR The mouse pointer also called the cursor may be changed with the CURSOR command GENERAL WINDOW AND CONTROL COMMANDS TRAPCLOSE This command sets a close event handler for a window or dialog When a user decide to close a window it branches to a routine specified by the trapclose command that confirms or does some sort of cleanup etc Branch Label for Close trapclose example using a branch label event handler statictext example label Now close the window 10 10 200 25 open Demonstrate trapclose for window as example print example trapclose branch wait branch confirm Really close answerS if answer no then wait close example end Subroutine for Close trapclose example using a subroutine event handler statictext example label Now close the window 10 10 200 25 open Demonstrate trapclose for window as example print example trapclose Branch wait sub Branch handle confirm Really close answerS if answerS no then wait close handle end end sub To send a trapclose command to text window precede the command with the character trapclos xample in text window open Demonstrate trapclose for text as example print example trapclose branch wait See also Trapping the close event FONT This command sets the font of all of the controls in a window set the font of all the control
153. default DLLs a reference to a like named handle will still resolve to the desired DLL This saves on code to open and close DLLs DLLs can still be opened with the OPEN statement Here are the default handles user32 kernel32 gdi32 winmm shell32 comdlg32 comctl32 Examples OPEN the DLL and give it a handle Open user32 for DLL as u Calldll u CloseWindow h as long result as boolean CLOSE the DLL close u or call the dll by its default handle no need to OPEN it or CLOSE it Calldll user32 CloseWindow h as long result as boolean See also STRUCT Using Types with CALLDLL What are APIs DLLs How to Make API Calls CHECKBOX M CheckBox CHECKBOX handle ext label setHandler resetHandler x y wide high Description This command adds a checkbox control to the window referenced by handle ext Checkboxes have two states set and reset They are useful for getting input of on off type information Here is a description of the parameters of the CHECKBOX statement handle ext This parameter specifies the handle for this control The handle part should be the same as the handle of the window containing the checkbox and the ext part names the checkbox uniquely in the window label This parameter contains the visible text of the checkbox setHandler This is the branch label or subroutine to go to when the user sets the checkbox by clicking on it When the checkbox is s
154. der3 holder3 sin holder2 20 ys 200 int sin holderl 50 int cos holder2 50 int cos holder3 15 terrain x y print lander goto x y next x goto endSub makeLandingZone width int rnd 1 4 2 3 for lz x to min 499 x 34 width terrain lz y print lander goto lz y next lz x lz return endSub end sub Calling APIs and DLLs Liberty BASIC can make 32 bit Windows API calls and also bind to third party Dynamic Link Libraries Liberty BASIC programmers now have access to hundreds of functions provided in Windows and from third party sources that can greatly increase productivity The following topics address many of the methods needed to make API calls Informational resources about APIs DLLs What are APlIs DLLs How to make API DLL calls Example Programs Using hexadecimal values Using Types with STRUCT and CALLDLL Passing Strings into API Calls Caveats Informational resources about APIs DLLs This help file is a basic introductio for using Windows APIs and DLLs in Liberty Basic Fora detailed understanding of reasons and procedures for using APIs and DLLs it is necessary to study a separate volume that explains Windows programming in detail Microsoft includes detailed references with its C compilers but it is usually good to supplement these with other books Here are some suggestions For a general understanding of Windows 95 32 bit Wi
155. dle This command has two forms as described above The first form causes the contents of the text window to be replaced with the contents of vamame and the second form causes the contents of the text window to be replaced with the contents of the stream referenced by handle This second form is useful for reading large text files quickly into the window Here is an example of the second form open Contents of AUTOEXEC BAT for text as aetext open C AUTOEXEC BAT for input as autoexec print aetext contents autoexec close autoexec stop here input a print handle contents string This command returns the entire text of the window After this command is issued the entire text is contained in the variable string print handle copy This command causes the currently selected text to be copied to the WINDOWS clipboard print handle cut This command causes the currently selected text to be cut out of the text window and copied to the WINDOWS clipboard print handle font fontName pointsize This command sets the font of the text window to the specified name and size If an exact match cannot be found then Liberty BASIC will try to match as closely as possible with size taking precedence over name in the match Note that a font with more than one word in its name is specified by joining each word with an underscore _ character For example the font Times New Roman
156. dle variables Here is an LB3 example where you have to define identical code once for each item create a window with a bunch of checkboxes and set them all checkbox win red Red redSet redReset 10 10 400 24 checkbox win blue Blue blueSet blueReset 10 35 400 24 checkbox win green Green greenSet greenReset 10 60 400 24 checkbox win yellow Yellow yellowSet yellowReset 10 85 400 24 checkbox win cyan Cyan cyanSet cyanReset 10 110 400 24 open The old handle way for window as win set each checkbox win red set win blue set win green set win yellow set win cyan set wait The new way In the code below it is no longer necessary to issue individual set commands for each checkbox as it was in the old way example above The checkbox handles can be expressed as variables and accessed in a FOR NEXT loop The variable var is reset each time though the loop The first time through the loop it has a value of win red the second time through the loop it has a value of win blue and so on To use it in place of a literal handle for a control it is written with the character in front so var is the handle variable associated with the string variable var create a window with a bunch of checkboxes and set them all checkbox win red Red redSet redReset 10 10 400 24 checkbox win blue Blue blueSet blueRes
157. documentation for the DLL will contain the information needed to call its functions handle This parameter is the handle that was given to the DLL when it was opened with the OPEN statement function This parameter is the name of the function enclosed in quotes It is case sensitive param 1 as type param2 as type2 This is a list of input parameters required by the function The number and TYPE of input parameters is dependent upon the function being called These parameters send information to the function so that it knows how to perform its task as needed by the program These parameters must be passed AS TYPE See Using Types with STRUCTS and CALLDLL for details The parameters will include information such as window or control handles text strings to display and so on return as returnType This parameter contains the value returned by the function It must also be of the correct TYPE expected by the function If a function does not return a value this parameter is passed AS VOID Usage This example calls the WINDOWS API to minimize a window and change its caption open An Example for window as main h hwnd main open user32 for dll as user calldll user CloseWindow _ h as long _ result as boolean calldll user SetWindowTextA h as long _ I was minimized as ptr _ result as void close user Liberty BASIC 3 has Enhanced DLL handle resolution If a program hasn t opened certain
158. does not fulfil any other CASE statements END SELECT signals the end of the SELECT CASE construct Example usage num 3 select case num case 1 print one case 2 print two case 3 print three case else print other number end select The example above results in output in the mainwin of three Strings SELECT CASE can also evaluate string expressions in a similar way to numeric expressions String example varS blue select case vars case red do stuff case green yellow do stuff case else do stuff end select MULTIPLE CASES may be evaluated when separated by commas For example select case atb case 4 5 do stuff case 6 7 8 do other stuff end select Once one of the CASEs has been met no other case statements are evaluated In the following example since the value meets the condition of the first CASE statement the second CASE statement isn t considered even though the value meets that condition also num 3 select case num case 3 5 10 print 3 5z 10 case 3 12 14 18 print 3 12 14 18 case else print Not evaluated end select The example above results in output in the mainwin of 3 5 10 Evaluating multiple conditions in the CASE statement Omitting the expression or variable in the SELECT CASE statement causes the conditions in the CASE statements to be evaluated in their entirety To omit the expression simply type select case with no variable or ex
159. dow it returns the window to its previous size and location Right Click Quickly press and release the right mouse button Right Click Menu An easy to use menu that opens when you right click an object Also called a shortcut menu object menu or context menu Right Drag A mouse action in which you move the pointer on an item hold down the right mouse button drag the pointer to a new location and release the right mouse button ROM Read Only Memory the computer s pre programmed memory Save The command that saves changes to a previously named document Save As A command that opens a dialog that permits you to save a new unnamed document or rename a previously saved one Scroll Arrows The arrows at each end of the scroll bar used to scroll through the contents of the window Scroll Bar A bar that appears at the right and or bottom edge of a window whose contents are not completely visible termed horizontal and vertical scroll bars Sequential Access The name given to the method of accessing the data in a file in the order from beginning to end of file Shell The most generic sense of the term shell means any program that users use to type commands it is called a shell because it hides the details of the underlying operating system behind the shell s interface Short Filename A filename that is no longer than eight characters and a three character extension Sizing Handle An area in the bottom ri
160. dows arrow CROSSHAIR a shaped pointer HOURGLASS the Windows hourglass TEXT the text insertion Lbeam Example cursor hourglass for i 1 ton perform some work next i cursor normal The program s code is responsible for setting the cursor back to the default normal when appropriate If a runtime error halts a program the cursor will automatically revert to normal DATA Description The DATA statement provides a convenient way to insert data into programs The DATA can be read once or many times using the READ statement A DATA statement doesn t actually perform an action when it is encountered in the program s code Example read the numbers and their descriptions while desc lt gt end read desch value print desc is the name for value wend here is our data data one 1 two 2 three 3 end 0 end One or more DATA statements form the whole set of data elements For example the data represented in the example above can also be listed in more than one DATA statement here is our data in two lines instead of one data one 1 two 2 data three 3 end 0 DATA is local to the subroutine or function it is defined in Error Handling An attempt to read more DATA items than are contained in the DATA lists causes the program to halt with an error Notice that in the examples above an end tag is placed in the DATA and when it is reached the program stops READing DATA This i
161. e John Q Public Address 456 Maple Street Anytown USA Rank Expert Programmer IDnumber 99 PUT 1 3 GET GET handle number This statement reads an entire record and fills the variables listed in the FIELD statement GET 1 3 Print Name would produce John Q Public Ww Print Address would produce 456 Maple Street Anytown USA Ww Print Rank would produce Expert Programmer d print IDnumber would produce 99 and so on GETTRIM GETTRIM handle number This command retrieves the record in the same manner as GET but it removes any blank leading or trailing spaces in the record GETTRIM 1 3 Print Name would produce John Q Public no blank spaces are included Testing for File Existence Here is a short user defined function which can be used to test if a file exists on disk It is important to know if a file exists because attempting to access a nonexistent file can cause a program to crash function fileExists path filename dimension the array infoS at the beginning of your program files path filenameS infoS fileExists val info 0 0 non zero is true end function If the file is to be in the default directory and named users dat this example shows how to test for its existence with the fileExists function dim info 10 10 if fileExists DefaultDir users dat then notice It s alive else notice Igor I need more powe
162. e Usage combobox demo with branch label event handler nomainwin a 1 one a 2 two a 3 three a 4 four combobox win combo a doCombo 10 10 120 200 open Combobox Demo for window as win win trapclose Quit win combo selectindex 1 wait Quit close win end doCombo win combo selection sels notice You chose sels wait combobox demo with subroutine event handler nomainwin a 1 one a 2 two a 3 three a 4 four combobox win combo a doCombo 10 10 120 200 open Combobox Demo for window as win win trapclose Quit win combo selectindex 1 wait sub Quit handles close handles end end sub sub doCombo handles handleS selection sel notice You chose sel end sub For information on creating controls with different background colors see Colors and the Graphical User Interface CommandLine CommandLine Description This special variable contains any switches that were added when Liberty BASIC was started This is especially useful in applications executing under the runtime engine It allows a tokenized program to receive information upon startup and act upon that information The CommandLine variable can be parsed in the same way as other strings to retrieve the information One way to extract information from the CommandLine is with INSTR The WORD and VAL functions can also be used to evaluate the contents
163. e that is used to open windows files etc For example a window can be opened as follows open Maphandle example for window as renameMe Once this window is open the code cannot execute this line again because the handle renameMe is in use by that window Opening another one is not allowed because a given handle can only be in use by one device at a time The maphandle command provides a way around this problem You can change the handle of the window after you open it Usage Maphandle Examples maphandle renameMe newHandle maphandle renameMe newHandle aS new Handle maphandle renameMe a With this example you see how to create handles dynamically on the fly if desired winNameS first second third for x 1 to 3 call createWindow word winName x next x wal ct ct sub createWindow titles texteditor Al Ce 10 10 200 200 open text title for window as 1 1 te this is the title window 1 trapclose aboutToClose handle S 4 titles maphandle 1 handle end sub sub aboutToClose handles confirm Close handleS answer if answer 1 then close handle end sub The old way Here is the old way of opening three windows without using maphandle and variable handles In some ways this is easier to read but it is a lot more code and you can only open another window by adding a lot more code texteditor 1 te 10 10 200 200 open text first for
164. e BACKGROUNDXY command must be issued before the DRAWSPRITES command print w g drawsprites DRAWING WITH GRAPHICS COMMANDS After the display has been updated with the DRAWSPRITES command graphics may be drawn with regular Liberty BASIC graphics commands like LINE CIRCLE BOXFILLED etc These commands must be reissued after each DRAWSPRITES command Liberty BASIC graphics commands should be used sparingly because this may result in flickering images To cause Liberty BASIC graphic entities to become a permanent part of the background the program must use the GETBMP command and then the BACKGROUND command to reset the background See the section on backgrounds for more information COLLISION DETECTION Most games require some form of collision detection to ascertain when two sprites have touched Liberty BASIC does this automatically The SPRITECOLLIDES command is used with INPUT to get a string with names of sprites that overlap the current frame of the sprite named The INPUT statement can be avoided if the list receiver variable is placed inside the quotation marks for the SPRITECOLLIDES command The sprite names are returned in a single string with spaces between them print w g spritecollides smiley input w g lists OR print w g spritecollides smiley list In the following example the first line reports that smiley collided with smiler smiled and smiles during that frame of animation The second line
165. e BASICs Liberty BASIC does not require variables to be declared before they may be used in code It is importatnt to check the spelling capitalization of variables because variable names are case sensitive If Compiler Reporting is enabled in the options dialog Liberty BASIC will give an alert in a special pane at the bottom of the editor when a program contains variables with similar names like name and names or name and Name GLOBAL In general variables used in the main program code are not visible inside functions and subroutines Variables inside functions and subroutines are not visible in the main program Liberty BASIC 4 introduces the GLOBAL statement to create global variables Variables declared as GLOBAL can be seen everywhere in a program The special system variables like WindowWidth WindowHeight etc now have true global status GLOBALS are specified and used like this global true false filenames true 1 false 0 filanameS readme txt Arrays Liberty BASIC supports single and double dimensioned arrays These can be defined as string or numeric arrays The extents of the dimensions can be in excess of 2 million elements if there is enough RAM available Arrays that contain more than 10 elements must be dimensioned before they can be used Arrays are dimensioned with the DIM statement DIM students 20 DIM ages 100 Resizing is done to any array with the REDIM statement but doing so will erase
166. e FLUSH command insures that it will always be yellow print w g down fill yellow print w g flush FLUSHING SPRITE GRAPHICS A simple FLUSH command will not work to flush graphics drawn with sprite commands It is possible to flush a sprite filled graphicsbox or graphic window It first requires a command to GETBMP BMPNAME X Y WIDTH HEIGHT The GETBMP comand must be followed by a DRAWBMP command that draws the named bitmap on the window or graphicbox in the same location It can then be FLUSHed It looks like this in a program print w g getbmp KeepIt 0 0 300 200 print w g drawbmp KeepIt 0 0 flush DON T FLUSH EVERY FRAME OF A SPRITE ANIMATION The flush command consumes memory The graphicbox can be updated easily when needed with the DRAWSPRITES command Ifthe sprites are part of an animated display each frame of animation can be flushed but it is important to remove old segments from memory It is rarely necessary to flush animated graphics because the display can be refreshed easily and the operations to flush and delete segments will slow down the animation Pauses and Timing CONTROLLING THE ANIMATION If the frames of animation are drawn with no pause the action may be too fast to see or control on faster computers A program can control the speed by drawing frames of animation at a set time interval with the TIMER or with a simple PAUSE SUBROUTINE A REAL TIMER The new Liberty BASIC TIM
167. e drawing program open drawing example for graphics nsb as draw draw vertscrollbar on 0 DisplayHeight draw horizscrollbar on 0 DisplayWidth draw down draw size 2 draw when leftButtonMove draw wait sub draw handleS x y handleS set x T j y end sub Mouse actions example with branch label event handler Here s a really simple illustrative example of a paint program When the leftButtonDown event happens the program branches to the draw routine Mouse coordinates are contained in MouseX and MouseY a simple drawing program open drawing example for graphics_nsb as draw draw vertscrollbar on 0 DisplayHeight draw horizscrollbar on 0 DisplayWidth draw down draw size 2 draw when leftButtonMove draw wait draw draw set MouseX Mouse wait Keyboard input example with subroutine event handler Here s a simple program that monitors user keypresses When the characterlnput event happens the keyCheck subroutine gets called and the graphicbox handle and Inkey values get passed in a simple keycheck program open Press some keys for graphics _nsb as draw draw setfocus place 10 20 draw when characterInput keyCheck wait sub keyCheck handleS key handleS key end sub Keyboard input example with branch label event handler Here s a simple program that monitors user keypresses When the characterlnput event happens the program branc
168. e main program Now Liberty BASIC 4 allows us to pass variables by reference This means that if a subroutine or function so declares it can modify the value of a variable passed in and when the subroutine or function ends and execution returns to the caller the change will be reflected in the variable that was used as a parameter in the call By default and without any direct instruction by the programmer parameters passed into user defined functions and subroutines in QBasic and Visual Basic are passed by reference That is not true in Liberty BASIC where values are passed by value as the default Passing by reference is only done when the BYREF keyword is used Example of passing by value This example shows how passing by value works The only value that comes back from the function is the one assigned to result when the function call returns this is the way it always worked x 5 3 y 7 2 resultS formatAndTruncateXandY x y print x x print y y print results end function formatAndTruncateXandY a b a int a b int b formatAndTruncateXandYy str a str b end function Example of passing by reference In contrast to the passing by value example each of the parameters in the function in this example are to be byref pass by reference This means that when the value of a and b are changed in the function that the variables used to make the call x and y will also be changed to reflec
169. ebugging Debugging Ioj EX Code File Edit b EBE a f E I UpperLeftyY Version WindowHe ight WindowWidth M Ontop Manually scroll variables IV Show default variables for x 1 to 1000 next x 08 17 52 Execution stopped Close the debugger This will also close the program window EXECUTING CODE AGAINST A RUNNING PROGRAM The combobox in the center of the debug window allows you to type commands to your program while it is being run for debug Clicking the Execute button will cause the code you have typed to be executed In the example above you might want to change the value of x Type into the code combobox x 50 Start stepping though the code by clicking the Step Into button several times then click the Execute button Click the Step Into button again See what happens to the printout in the mainwindow It looks like this OO PrP WN EF The combobox contains a list of all code that you ve typed into it during the course of debugging To go back to a previous line of code simply choose it from the drop down list of the combobox and then click the Execute button BREAKPOINTS Liberty BASIC 4 adds the ability to add a breakpoint to your program so that when you are debugging the program will stop at the breakpoint when it reaches it To add a breakpoint point with your mouse at the breakpoint bar on the left side of the editor and double click A breakpoint marker will appear If you double click
170. eceive the input focus This means that any keypresses will be directed to the control print handle ext enable This causes the control to be enabled print handle ext disable This causes the control to be inactive It can no longer capture mouse and keyboard events print handle ext show This causes the control to be visible print handle ext hide This causes the control to be hidden or invisible print handle autoresize This causes the edges of the control to maintain their distance from the edges of the overall window If the user resizes the window the graphicbox control also resizes Graphics commands in alphabetical order print handle backcolor COLOR This command sets the color used when drawn figures are filled with a color The same colors are available as with the COLOR command below print handle backcolor red 0 255 green 0 255 blue 0 255 The second form of backcolor specifies a pure RGB color This only works with display modes greater than 256 colors To create a green blue color for example mix green and blue print handle backcolor 0 127 200 print handle box x y This command draws a box using the pen position as one corner and x y as the other corner print handle boxfilled x y This command draws a box using the pen position as one corner and x y as the other corner The box is filled with the color specified using the other BACKCOLOR command print handle ci
171. ecifies a simple rectangle and right aligns the given text in the rectangle SUB See also Functions and Subroutines BYREF sub subName zero or more comma separated parameter variable names code for the sub goes in here end sub Description This statement defines a subroutine Zero or more parameters may be passed into the subroutine A subroutine cannot contain another subroutine definition nor a function definition The CALL statement is used to access the SUBROUTINE and to pass values into it The values must be the same type as the SUB statement defines them to be So the following example sub mySubName string number string2 is called like this call mySubName string value 123 str 321 Local Variables The variable names inside a subroutine are scoped locally meaning that the value of any variable inside a subroutine is different from the value of a variable of the same name outside the subroutine Passing by Reference Variables passed as arguments into subroutines are passed by value which means that a copy of the variable is passed into the subroutine The value of the variable is not changed in the main program if it is changed in the subroutine A variable may instead by passed byref which means that a reference to the actual variable is passed and a change in the value of this variable in the subroutine affects the value of the variable in the main program Global Variables and Devices Variables dec
172. ecord n for h Command Reference A C D F G K L M N P R S T Z Command Reference R S Commands and Keywords A C D F G K L M N P R S T Z RADIOBUTTON adds a radiobutton to a window RANDOM purpose parameter in fileopen statement RANDOMIZE seed the random number generator READ reads information from DATA statements REDIM redimensions an array and resets its contents redraw graphics command to redraw segment refresh redraw a window REM adds a remark to a program removesprite remove a sprite resizehandler set up a routine to handle window resize by user RESTORE sets the position of the next DATA statement to read RETURN return from a subroutine call RIGHT s n n rightmost characters of s RMDIR removea subdirectory RND n returns a random number rule graphics command to set drawing rule RUN s mode run external program s with optional mode SCAN checks for and dispatches user actions SEEK h fpos set the position in a file opened for binary access segment graphics command to return segment ID SELECT CASE performs conditional actions Iselect text command to place caret Iselectall text command to highlight all text Iselection text command to return highlighted text set graphics command to draw a point setfocus set input focus to control or window SHORT data type for calldll and structs SHOW make a control visible SIN n sine of n size graphics command to set pen size SORT sorts
173. ed The following command moves the sprite named smiley 5 pixels in the x direction and 2 pixels in the y direction each time a new animation frame is drawn print w g spritemovexy smiley 5 2 A sprite is stopped from moving automatically by the SPRITEMOVEXY command and values of 0 for the x and y movement print w g spritemovexy smiley 0 0 The spritetravelxy command sets up a condition where a sprite moveS to a given location at a certain speed Each time a drawsprites command is issued the sprite moves the appropriate amount towards its goal When it reaches its destination it will fire an event using the handler specified and it will stop moving print w g spritetravelxy smiley 300 200 5 landed The centersprite command causes any commands that refer to the sprite s location to use the center of the sprite as the x y location rather than using the default upper left corner of the sprite as the x y location print w g centersprite smiley The spriteoffset command causes the displayed location of the sprite to be offset by the values indicated from the actual coded x y location Ifa sprite is given a spritexy command that calls for it to be located at 100 100 but the spriteoffset command is in force giving offsets of 20x and 50y the sprite appears at 120 150 This alters the display coordinates of the sprite but not its actual coordinates which remain 100 100 in this example print w g spriteoffset
174. eds to run continuously but which still needs to process button clicks and other actions In this way SCAN can be used as an INPUT statement that doesn t stop and wait Example scan example digital clock nomainwin WindowWidth 120 WindowHeight 95 statictext clock time xx xx xx 15 10 90 20 button clock 12hour 12 Hour twelveHour UL _ 15 40 40 20 button clock 24hour 24 Hour twentyfourHour UL _ 60 40 40 20 open Clock for window_nf as clock print clock trapclose quit print clock time font courier new 8 15 print clock 12hour font ariel 5 11 print clock 24hour font ariel 5 11 goto twelveHour timeLoop if timeS lt gt timeS then timeS times gosub formatTime print clock time formattedTimes end if scan check for user input goto timeLoop formatTime hours val left timeS 2 if twelveHourFormat 1 then if hours gt 12 then hours hours 12 suffixS PM else if hours 0 then hours 12 suffixS AM end if else suffixs Dn end if formattedTime prefixS right 0 strs hours 2 formattedTime formattedTimeS mid time 3 suffix return twelveHour set up twelve hour mode twelveHourFormat 1 time prefix S goto timeLoop twentyfourHour set up twentyfour hour mode twelveHourFormat 0 time prefix goto timeLoop quit exit our clock close cl
175. eful not to delete or modify uninstall ini because it contains the information about the installation that will be used by the uninstall program Registering Liberty BASIC Liberty BASIC v4 can be registered with two different licenses The SILVER license 29 95 Remove the size limitation on compiling so you can create large programs Turn off the reminder popups that appear when using Liberty BASIC Receive tech support The GOLD license 49 95 With this license you get all these features that come with the SILVER license Remove the size limitation on compiling so you can create large programs Turn off the reminder popups that appear when using Liberty BASIC Receive tech support PLUS Create applications that run standalone using the runtime engine This special mechanism lets you create programs you can share freely or sell Note to registered users of Liberty BASIC v1x and v2 x and 3 x We also have low upgrade prices What is the runtime engine It is a program named RUN400 EXE which comes with the shareware version of Liberty BASIC It lets you and others run applications that you write in Liberty BASIC without giving away your painstakingly written BASIC code and without needing to distribute the Liberty BASIC development tools The runtime engine will only run applications compiled by the registered version of Liberty BASIC To order by postal mail print a copy of register txt which can be found
176. eight h The ellipse is filled with the color specified using the command backcolor see above print handle fill COLOR Or print handle fill red 0 255 green 0 255 blue 0 255 This command fills the window with COLOR For a list of accepted colors see the COLOR command above The second form specifies a pure RGB color This only works with display modes greater than 256 colors print handle flush This command ensures that drawn graphics stick Each time a flush command is issued after one or more drawing operations a new group called a segment is created Each segment of drawn items has an ID number The segment command retrieves the ID number of the current segment Each time a segment is flushed a new empty segment is created and the ID number increases by one See also the commands cls delsegment discard redraw and segment print handle flush segmentName This command ensures that drawn graphics stick and assigns a name to the flushed segment Each time a flush command is issued after one or more drawing operations a new group called a segment is created This assigned name can be used in later commands to manipulate the segment See also the commands cls delsegment discard redraw and segment print handle font facename pointSize This command sets the pen s font to the specified face and point size If an exact match cannot be found then Liberty BASIC will try to find a close match with size
177. eimage SpriteName BmpNameX This causes the sprite called SpriteName to be shown as the image from its image list called BmpNamex SPRITEMOVEXY print w g spritemovexy SpriteName 5 5 OR x 5 y 5 print w g spritemovxy SpriteName x y This causes a sprite called SpriteName to move x pixels in the x direction and y pixels in the y direction each time a DRAWSPRITES command is issued to update the display SPRITEOFFSET print w g spriteoffset SpriteName 20 20 OR x 20 y 20 print w g spriteoffset SpriteName x y This causes the sprite x y display location to be offset by the values indicated in x and y from its coded x y location SPRITEORIENT print w g spriteorient SpriteName normal print w g spriteorient SpriteName flip print w g spriteorient SpriteName mirror print w g spriteorient SpriteName rotatel80 This causes the sprite called SpriteName to be oriented in one of the four directions normal flip mirror rotate180 SPRITEROUND print w g spriteround SpriteName This causes the sprite called SpriteName to be assumed to be a rounded area within the rectangular bitmap when collisions are evaluated SPRITESCALE print w g spritescale SpriteName 150 OR percent 150 print w g spritescale SpriteName percent This causes the sprite called SpriteName to be scaled by the percentage designated in both width and height SPRITETOBACK print w g sprit
178. eir sum must be equal to the length that was set with the LEN parameter in the OPEN statement In the above case the field lengths must total 256 A character indicates that a field holds data that will be accessed as a string If there is no character the field will be accessed as a number The fields for members dat might look like this OPEN members dat FOR RANDOM AS 1 LEN 256 FIELD 1 _ set up the fields for file opened as 1 90 AS Namen lst 90 bytes contains Name string 110 AS Address 2nd 110 bytes contains Address string 50 AS Ranks 3rd 50 bytes contains Rank string 6 AS IDnumber 4th 6 bytes contains IDnumber numeric The value after LEN is 256 which is obtained by adding 90 110 50 6 or the total length of all the fields in FIELD The FIELD statement must follow the OPEN statement and must be used before trying to read or write data to the file with GET or PUT PUT PUT handle number This statement is used to write the data that is contained in the variables listed in the FIELD statement to the specified record number Records in RANDOM files are numbered beginning at 1 not 0 Ifthe length of a variable in a given field is shorter than the field length specified blank spaces are added to pad it If the length of the variable is larger it will be truncated to the length specified in the FIELD statement To add this data as RECORD number 3 to the file referenced above Nam
179. elected value does not fulfil any other CASE statements END SELECT signals the end of the SELECT CASE construct Example usage num 3 select case num case 1 print one case 2 print two case 3 print three case else print other number end select The example above results in output in the mainwin of three Strings SELECT CASE can also evaluate string expressions in a similar way to numeric expressions String example var S blue select case vars case red print red case green yellow print green or yellow case else print color unknown end select MULTIPLE CASES may be evaluated when separated by a comma For example select case atb case 4 5 do stuff case 6 7 do other stuff end select Once one of the CASEs has been met no other case statements are evaluated In the following example since the value meets the condition of the first CASE statement the second CASE statement isn t considered even though the value meets that condition also num 3 select case num case 3 5 10 prine 3 57 10 case 3 12 14 18 print 3y T27 14 18 case else print Not evaluated end select The example above results in output in the mainwin of 3 5 10 Evaluating multiple conditions in the CASE statement Omitting the expression or variable in the SELECT CASE statement causes the conditions in the CASE statements to be evaluated in their entirety To omit the expression simpl
180. em The letter directly following the amp character will act as a hotkey for that menu item when it is pressed while the user presses and holds down the ALT key The hotkey appears underlined in the menu display The menu command must be contained on one line To break the line for viewing in the Liberty BASIC editor use the line continuation character _ Usage Here is an example that adds a menu to a graphics window menu geo amp Colors amp Red setRed amp Green setGreen EBlue setBlue menu geo amp Shapes amp Rectangle asRect amp Circle asCircle amp Line asLine open Geometric White board for graphics nsb as geo wait stop and wait for a menu item to be chosen Notice that the MENU commands must go before the OPEN statement and must use the same handle as the window geo in this case Here is an example that uses subs as event handlers menu main testing Testing one one two two button main close Close quit UL 10 10 open example for window as main main trapclose quit wait sub one notice One end sub sub two notice Two end sub sub quit handles if instr handles then handle left handleS instr handleS 1 end if close handle end end sub Textboxes and texteditors cause an automatic EDIT menu to be added to the menu bar To locate this automatic menu use the menu command with a menu name of edit
181. en selected will be a string of zero length a null string print handle ext selectionindex index This places the index of the selected string into the variable called index If there is no selected item then index will be set to 0 print handle ext reload This reloads the combobox with the current contents of its array and updates the display print handle ext setfocus This causes the combobox to receive the input focus This means that any keypresses are directed to the combobox print handle ext locate x y width height This repositions the combobox control in its window This only works if the control is placed inside window of type window The control will not update its size and location until a REFRESH command is sent to the window See the RESIZER BAS example program print handle ext font facename pointSize This sets the combox s font to the specified face and point size If an exact match cannot be found then Liberty BASIC will try to find a close match with size taking precedence over face For more on specifying fonts read How to Specify Fonts Example print handle ext font times new roman 10 print handle ext enable This causes the control to be enabled print handle ext disable This causes the control to be inactive and grayed out print handle ext show This causes the control to be visible print handle ext hide This causes the control to be hidden or invisibl
182. enReplacingConfirm nil 260 70 130 20 radiobutton cfg Anever Never neverConfirm nil _ 260 95 130 20 groupbox cfg Confirm Close Operations 20 20 200 140 radiobutton cfg always Always alwaysClose nil 40 45 130 20 radiobutton cfg whenReplacing When Replacing whenReplacingClose nil 40 70 130 20 radiobutton cfg never Never neverClose nil 40 95 130 20 button cfg T amp OK D cfgOk UL 450 30 open Action Confirmation Setup for dialog as cfg print cfg trapclose cfgOk print cfg Anever set print cfg never set inputLoop wait alwaysConfirm statusS Always Confirm wait whenReplacingConfirm status When Replacing Confirm wait neverConfirm status Never Confirm wait alwaysClose cstatusS Always Close wait whenReplacingClose cstatus When Replacing Close wait neverClose cstatus Never Close wait cfg0k msg status chr 13 cstatus chr 13 msg msg Save this configuration confirm msg answer perform some sort of save for config here close cfg end nil wait demonstrates radiobuttons with subroutine event handler nomainwin global status radiobutton win yes Yes doRadio dummy 10 45 130 20 radiobutton win no No doRadio dummy 10 70 130 20 open Make a Choice for window as win print win trapclose Quit print win ye
183. end select end sub loadData for x 0 to 2 read aS pet x a next x for x 0 to 2 read a vehicle x a next x return data dog cat birada data car bike boat end 150 10 150 Window and Dialog Commands Note that Liberty BASIC 3 allows tabbing through controls in windows of type window as well as in windows of type dialog Tabbing through the controls means that controls will be highlighted and receive the input focus in turn each time the user hits the TAB key When the user presses the TAB key the next control listed will receive the input focus Changing the handle of a window dynamically at runtime can be accomplished with the MAPHANDLE command Dialog Default Button In a dialog window one button may be given the extension default If the user presses the ENTER key while in the dialog window it will be the same as if the button whose extension is default is pressed and program execution will continue at the event handler branchLabel for that button In the example below the program branches to the okay routine when the user presses ENTER button win default Okay okay UL 200 100 open Test for dialog as win The default extension only works this way for regular buttons not for bmpbuttons Change in behavior for LB3 If any button has focus it becomes the default button in a dialog window If any other kind of control has the focus the button designate
184. eral of the QBasic error codes are supported but some are not relevant and there are some new ones When an error occurs the special variables Err and Err hold numeric and string values describing what sort of error happened Some kinds of errors do not have a numeric value in which case Err will be zero If an error occurs in a user function or subroutine Liberty BASIC will exit the current function or subroutine and continue to exit functions and subroutines until it finds ON ERROR handler If an error is encountered a program can attempt to resume execution with the RESUME statement Here is a short list of error codes RETURN without GOSUB Read past end of data Branch label not found Subscript out of range Division by zero OS Error The system cannot find the file specified OS Error Cannot create a file when that file already exists Error opening file Bad file handle 62 Input past end of file OO OO OO A oO OR Ww M OO GO A Usage on error goto errorHandler open sSillyfilename txt for input as f close f end errorHandler print Error string is chr 34 Err chr 34 print Error number is Err end The program above will print the following in the mainwin Error string is OS Error The system cannot find the fil Error number is 53 demonstrate the use of RESUME on error goto whoops global divideBy call causeWhoops end specified whoop
185. erty BASIC In order to run the code with Liberty BASIC from another program use the following startup options to LIBERTY EXE R Run a BAS file on startup D Debug a BAS file on startup EE the following three are in the registered version only T Make a TKN file from a BAS file on startup A Automatically Exit LB on completion of BAS file M Minimize the Liberty BASIC editor on startup Examples LIBERTY R M PROG BAS run PROG BAS with editor minimized LIBERTY T A PROG BAS create a TKN file from PROG BAS then exit IBERTY D PROG BAS run the debugger on PROG BAS As it appears when used in a code editor written in Liberty BASIC RUN LIBERTY R M PROG BAS run PROG BAS with editor minimized RUN LIBERTY T A PROG BAS create a TKN file from PROG BAS then exit RUN LIBERTY D PROG BAS run the debugger on PROG BAS Using Inkey Liberty BASIC has a special variable named Inkey which can be used to fetch keys pressed This only works with the graphicbox and with windows opened for graphics Graphics controls handle an event called characterlnput which copies pressed key codes into the Inkey variable See Graphics Commands Inkey Reading Mouse Events and Keystrokes and Using Virtual Key Contants with Inkey for more details Here is a very short program demonstrating Inkey Inkey example print Keys pressed open print graph print graph when chara
186. erty BASIC numeric variables hold either a double precision floating point value or an integer A floating point value will be converted to an integer if its fractional part is zero when it is assigned to a variable Integers in Liberty BASIC can be huge Only nine digits are displayed when floating point values are printed unless the USING function is used to force the display of the number of digits desired after the decimal point When first referenced numeric variables equal 0 Values are assigned to variables with the equals sign myVar 42 In the following code the variable totalNum is 0 to begin so adding 3 to it gives it a value of 3 Adding 8 to it in the next line gives it a value of 11 totalNum totalNum 3 totalNum now contains the value 3 totalNum totalNum 8 totalNum now contains the value 11 NOTE Liberty BASIC does not support the CONST keyword that is common in some other forms of BASIC such as QBASIC Negative numbers Liberty BASIC does not support changing the sign of a variable directly by preceding it with a negative sign Instead the variable must be multiplied by 1 WILL NOT WORK numl 7 num2 numl print num2 USE THIS METHOD numl 7 num2 1 numl print num2 GLOBAL In general variables used in the main program code are not visible inside functions and subroutines Variables inside functions and subroutines are not visible in the main program Liberty
187. es of Liberty BASIC To do this send email to support libertybasic com and explain in as much detail as you can how the error happened If you aren t sure how it happened see if you can make the error happen again It can be very hard or nearly impossible to fix bugs when they cannot be recreated Sometimes it helps us to figure out the cause of the error when we have access to the source code and other files that you were using when the error happened If you can please provide us with these things so that we can serve you best We realize of course that sometimes you may not want to share your code and files for privacy reasons or because your company policy may forbid it and this is perfectly understandable Now that you have a better understanding of what ERROR LOG is and how to make use of it you will be able to help us improve the quality of the Liberty BASIC programming language Port I O Distributing your application using INP and or OUT to control hardware ports Because 32 bit versions of Windows do not have a built in API for doing hardware I O you will need to distribute driver files with your Liberty BASIC application if it requires the use of INP and OUT You can find all runtime files you need to distribute in the ntport subdirectory of your Liberty BASIC v3 0 install They are ntport dll Application Dynamic Link Library zntport sys Windows NT 2000 XP driver For Windows 95 98 ME When you install your applic
188. et 10 35 400 24 checkbox win green Green greenSet greenReset 10 60 400 24 checkbox win yellow Yellow yellowSet yellowReset 10 85 400 24 checkbox win cyan Cyan cyanSet cyanReset 10 110 400 24 open The new handle variable way for window as win set each checkbox for x 1to5 varS win wordS red blue green yellow cyan x vars set next x wait Understanding Syntax The documentation for Liberty BASIC commands includes command definitions in example form These are not to be taken literally The language used attempts to give intuitive labels to the command parameters For example finding an x within a command definition doesn t meant that an actual x should appear there but rather that the value desired for the x placement should appear there Here are some examples to explain the way it works Graphics Commands In the following graphics command definition the x and y are NOT variables but placeholders for hard coded values print handle box x y In an actual program the values required would appear within the quotation marks for the command print win box 30 221 To use the x and y as variables they MUST be placed outside the quotation marks with blank spaces preserved within quotation marks x 30 y 221 print main box x y See also Graphics Commands Text Commands print handle select column row Text command
189. et it displays a checkmark See also Controls and Events resetHandler This is the branch label or subroutine to goto when the user resets the checkbox by clicking on it When the checkbox is reset the checkmark is removed See also Controls and Events x This is the x position of the checkbox relative to the upper left corner of the window it belongs to This is the y position of the checkbox relative to the upper left corner of the window it belongs to wide This is the width of the checkbox control high This is the height of the checkbox control Checkbox Commands Checkboxes understand these commands print handle ext set This sets the checkbox causing a checkmark to appear within it print handle ext reset This resets the checkbox clearing it print handle ext value result The result variable is set to the status of the checkbox either set or reset print handle ext setfocus This causes the checkbox to receive the input focus This means that any keypresses are directed to the checkbox print handle ext locate x y width height This repositions the checkbox in its window This is effective when the checkbox is placed inside window of type window The checkbox will not update its size and location until a REFRESH command is sent to the window See the RESIZE BAS example program print handle font facename pointSize This sets the font to the specified face and point size If an exa
190. etoback SpriteName This causes the sprite called SpriteName to be drawn first so that it appears underneath other sprites SPRITETOFRONT print w g spritetofront SpriteName This causes the sprite called SpriteName to be drawn last so that it appears on top of other sprites SPRITETRAVELXY w g Spritetravelxy SpriteName 200 250 5 landed or w g Spritetravelxy SpriteName X Y speed branchHandler or w g Spritetravelxy SpriteName X Y speed subHandler This causes the sprite called SpriteName to travel to the x y location specified at the speed indicated and to fire an event when it reaches the destination The event can be handled at a branchLabel or a sub SPRITEVISIBLE print w g spritevisible SpriteName on print w g spritevisible SpriteName off This causes the sprite called SpriteName to be visible if on is used or to be invisible if off is designated SPRITEXY print w g spritexy SpriteName 100 137 OR x 100 y 137 print w g spritexy SpriteName x y This causes the sprite called SpriteName to be drawn at position x y the next time the display is updated with the DRAWSPRITES command SPRITEXY print w g spritexy SpriteName input w g X y OR print 2 g spritexy SpriteName x y This obtains the coordinates of the sprite called SpriteName and places them into the variables x and y What is a Sprite He
191. eturns the nth word in the string string variable or string expression stringExpression The leading and trailing spaces are stripped from stringExpression and then by default it is broken down into words at the remaining spaces inside Ifn is less than 1 or greater than the number of words in stringExpression then is returned The string delimiter is optional When it is not used the space character is the delimiter Usage print wordS The quick brown fox jumped over the lazy dog 5 Produces jumped And display each word of sentenceS on its own line sentence S and many miles to go before I sleep token S while token lt gt index index 1 token word sentenceS index print tokens wend Produces and many miles to go before sleep Using the optional string delimiter You can now specify the delimiter string of one or more characters so optionally you can read comma delimited or other strings token parseMeS this is a test idx 0 while token lt gt idx idx 1 token S wordS parseMeS idx if token lt gt then print token wend Also notice the doubled up comma in the test string This will be returned as a comma This is useful for detecting empty delimited fields in a string Try substituting the following lines parseMeS thisarfisarfarfaarftest and token S wordS parseMeS idx arf Resize bas resize bas This is an exam
192. evaluations A boolean value is either true or false When used as types in CallIDLL booleans evaluate to 0 false nonzero true A true value is any value not zero but is usually considered to be either 4 UI or f E Boolean Conditions Tests that are placed into conditional clauses like IF THEN WHILE WEND and CASE statements return a boolean value Here is an evaluation if x lt 3 then doSomething The code is evaluating the condition x lt 3 and branching to the doSomething label if the condition is TRUE Ifthe value of x is 1 then the condition evaluates to TRUE and the program branches to doSomething If the value of x is 7 then the condition evaluates to FALSE and the program does NOT branch to doSomething Boolean Operators a b a is equal to b lt a lt b a is less than b lt a ze bh ais less than or equal to b gt a gt b a is less than b gt a gt b ais less than or equal to b lt gt a cz b ais not equal to b Multiple Conditions When evaluating multiple conditions each condition must be placed inside parentheses as in the examples below AND both conditions must be met for the test to evaluate to TRUE a 2 be 5 If a lt 4 and b 5 then doSomething In this code a must be less than 4 AND b must be equal to 5 for the program to branch to doSomething Since both of these conditions are true the program will advance to doSomething a 14 bz H If a lt 4 and b 5 then
193. example WINRECT BAS show how to get window position and size and demonstrate how to use the struct statement struct winRect _ orgX as long _ orgY as long _ crnrX as long _ crnrY as long open test me for window as win open user32 dl11 for dll as user hndl hwnd win calldll user GetWindowRect hndl as ulong _ winRect as struct result as long print Upper Left x y of test me print winRect orgX struct winRect orgY struct print print Lower Right x y of test me print winRect crnrX struct winRect crnrY struct close user close win wait end See also CALLDLL Using Types with STRUCT Understanding Syntax STYLEBITS stylebits handle addBits removeBits addExtendedBits removeExtendecBits Description STYLEBITS allows you to change the style of a Liberty BASIC window or control It accepts a handle and four parameters When the window is opened it checks to see if there are style bits for the window or for any controls If there is a STYLEBITS command it applies the remove bits first then applies the add bits In this way the control is created from the get go with the desired style The STYLEBITS command must be issued before the command to open the window This command works on all Liberty BASIC windows and controls but since the texteditor is nota native Windows control you will only be able to do things like tweak it s border and perhaps a few other things
194. exteditors do not work well in dialog windows because hitting ENTER is trapped by the window and the user cannot add a carriage return to text in a texteditor Dialog windows are best suited for getting information from a user although it is possible to have applications that are dialog based Dialog windows may display as modal This means that they receive the input focus for the program until they are closed Other program windows cannot be accessed by a user while a modal dialog is displayed Text Windows of type text are quite limited in their functionality They are not meant to contain other controls They are useful for displaying text to a user or for allowing a user to write and edit text Text windows always have a menubar that contains a ready made File Menu and a ready made Edit Menu Window types graphics open a graphics window graphics_fs open a graphics window full screen size of the screen graphics_nsb open a graphics window w no scroll bars graphics_fs_nsb open a graphics window full screen w no scroll bars graphics_nf_nsb open a graphics window with no sizing frame or scroll bars Graphics Commands text open a text window text_fs open a text window full screen text_nsb open a text window w no scroll bars text_nsb_ins open a text window w no scroll bars with inset editor Text Commands window open a basic window type window_nf open a basic window type without a sizing frame window_popup open a window wi
195. f code is highlighted in the debugger 2 Program named untitled bas Iof x Die Edit Click a few more times on the Step Into button until the value of x is 3 or maybe 4 The Step Into button must be pressed each time you want the program to execute a new line of code Now click on the Animate button This mode causes the program to execute while still documenting the current line of code and the values of variables in the debugging window This time you ll see the program running really fast and printing lots of numbers Quickly press the Step Into button again to stop the program The program will stop executing and you can see the current values for variables and the line that is to be executed next Debugging Debugging Ioj EX Code File Edit b EBE a f E I UpperLeftyY Version WindowHe ight WindowWidth IT Ontop Manually scroll variables MV Show default variables for x 1 to 1000 print x 08 17 52 Execution stopped Press the Resume button but get ready to press the Step Into button again Resume mode executes the code at normal speed and it doesn t document anything in the panes of the debugging window The numbers will start printing really quickly in the program window but the debugger doesn t show any activity at all You should still be able to click on the Step Into button again before the count reaches 1000 The debugger again shows you the current state of the program D
196. g end Graphical elements which display text will accept and display text that is PRINTed directly into them texteditor main txtEdit 3 3 250 300 open Edit some text man for window as main print main trapclose quit print main txtEdit C mon and edit me print main txtEdit I dare you print main txtEdit Or just start typing to replace me print main txtEdit selectall wait quit close main end The text PRINTed to the texteditor control is displayed on the control Because it accepts text to display it is necessary to prefix any commands with a when they are PRINTed to a text control as the selectall command shows Sending Commands See also Understanding Syntax how to use literals and variables in commands New to Liberty BASIC 3 it is no longer necessary to use the PRINT statement when issuing commands to a window or control The word print is optional as is the comma after the window or control handle If these are omitted Liberty BASIC adds them in the compiling process The PRINT statement may only be omitted when sending commands to windows and controls It cannot be omitted when PRINTing to files or other devices Here are some examples of sending commands to a window The old way open My Text Window for text as txtWin print txtWin The fox jumped over the dog print txtWin trapclose quit wait quit close txtWin end The following vers
197. g and numeric data easier DATA is accessed by the program with the READ statement which reads the DATA items in sequence The RESTORE statement causes the next READ statement to start at the first DATA statement listed or at the first DATA statement following a specified branch label if one is included in the RESTORE statement These methods can be used to put data into arrays thus providing an easy method for filling arrays DATA The DATA statement provides a convenient way to insert data into programs The DATA can be read once or many times using the READ statement A DATA statement doesn t actually perform an action when it is encountered in the program s code data one 1 two 2 three 3 end 0 One or more DATA statements form the whole set of data elements For example the data represented in the example above can also be listed in more than one DATA statement here is our data in two lines instead of one data one 1 two 2 data three 3 end U DATA is local to the subroutine or function in which it is defined READ This fetches the next strings and or numeric values from DATA statements in a program The READ statement will fetch enough items to fill the variable names that the programmer specifies The values fetched will be converted to fit the variables listed string or numeric Example read the numbers and their descriptions while desch lt gt end read desc value print desc is t
198. ght corner of a window that can be sized it is used to size the window You can however size a window from any corner Software Computer program written to perform specific tasks such as a word processor or spreadsheet Spreadsheet A program that automates an accountant s worksheet Status Bar The bar at the bottom of a program window it displays information about the program Statement A meaningful expression or generalized instruction in a computer programming language String The programming term for a series string of text characters Subfolder A folder that is within another folder Traditionally called a subdirectory Subprogram also called Subroutine A set of instructions in a computer program which is separated from other code to reduce reduncancey and called by other subprograms or other parts of the program Taskbar The portion of your screen including the Start button the time display and everything in between Title Bar The horizontal bar at the top of a window that displays the window s name The window s name is usually the name of the program running in the window Toolbar A row of buttons that provide quick access to commonly used commands Unzip To decompress or expand a file that has been made smaller using a compression utility Variable A name given to a piece of data in a computer program whose value may vary as the program executes WAV The extension used on some types of audio file
199. grams should finish executing with an END statement like the example above to ensure that programs actually do clean up by themselves Ifa program continues running with no way to close it it may be ended by clicking on the Run menu on the Liberty BASIC editor and selecting Kill BASIC Programs Functions and Subroutines See also Function Sub Branch Labels GOTO and GOSUB GOSUB RETURN GOTO GLOBAL BYREF Liberty BASIC supports user defined functions and subroutines They look similar to their QBASIC equivalents define a function for returning a square root function squareRoot value squareRoot value 0 5 end function and create a subroutine for logging to an event log sub logToFile logString open c logdir event log for append as event print event timeS print event logString close event end sub A user defined function such as the one above can be treated like any built in function print The square root of 5 is squareRoot 5 Subroutines in Liberty BASIC are accessed using the CALL statement For example Now log some info to disk call logToFile The square root of 5 is squareRoot 5 The variable scoping in subroutines and functions is local This means that by default the names given to variables inside the definition of a subroutine or function are only meaningful inside that definition For example a variable named counter can exist in the main program code The program
200. grees loop back 30 times make the image stick wait for button press dialog to confirm exit if answer no loop back Handle Variables In versions of Liberty BASIC prior to version 4 the manipulation of files and windows was done using statically declared handles for each file window or GUI control Now you can create more reusable code because handle variables allow you to pass a handle using a string form A handle variable looks like the regular handle but it adds a on the end like a string variable Regular handle myHandle Handle variable myHandleVariable The handle variable maps to the string variable of the same name which contains the actual handle Here is a simple example that fills the variable called var with a control handle then uses the associated handle variable called var to send a command to the checkbox create a window with a checkbox and set it checkbox win red Red redSet redReset 10 10 400 24 open The new handle variable way for window as win fill a var with the handle of the checkbox var win red now use the associated handle variable to set the checkbox vars set wait The handle variables are most useful when accessed in FOR NEXT loops thus eliminating many lines of code They are also essential when using subroutines as event handlers as in the TRAPCLOSE statement See the examples that follow The old way Liberty BASIC 3 doesn t have han
201. hat it terminates properly with an END statement Otherwise your program s windows may all be closed giving the illusion that it has stopped running Your Distribution Packet Your program s TKN file plus run400 exe rename to match your TKN and all of the other files in the list above must be included in your distribution You must also include any other files used by your program such as data files text files and bitmaps If all of these files are distributed together then someone who does not have the Liberty BASIC language installed on his computer can run your program by clicking on its icon or by double clicking on the EXE name in the list in My Computer or Windows Explorer Liberty BASIC Iof E Se 5 gt H A Back maar Up Cut Copy Paste Name Size Type Modfed zl exit while bas 1KB BAS 7 17 01 11 17 PM Exponent bas 1KB BAS 2 2 96 4 41 PM KR Factoril bas 1KB BAS 11 2 00 6 53 4M fflite ini IER Configuratio 12 30 01 4 24 AM Fform300 bas 94KB BAS 8 1 01 7 52 AM Ne 989KB Application 12 29 01 10 18 Ph gl Fform300 tk 95KB Liberty BASI 12 29 01 8 30 PM Files bas 1KB BAS 12 2 95 11 36 AM Fontbug bas AER BAS 3 24 97 11 56 PM Fontdlg bas 1KB BAS 12 6 00 10 45 PM Fontpowr bas 1KB BAS 3 21 00 9 03 PM fonttest has AED RAS 11210201 12 36 PLE 1 objects selected E My Computer Z File Edit View Go Favorites Help Additional Distribution
202. he filespec parameter contains the full or relative path and filename of the bmp file containing the bitmap image that will appear on the button There are no width or height parameters in the bmpbutton statement so the size of the button cannot be set by the program It is determined by the size of the bitmap image that will appear on it See also Path and Filename returnVar returnVar is expressed as one word and it is not enclosed in quotes It cannot be expressed as a string variable It must begin with a letter but it can contain numerals as well If returnVar is set to a valid branch label enclosed in square brackets then a button click will cause program execution to continue at the specified branch label The code that follows the branch label will be executed when the button is pressed If returnVar is the name of a subroutine then that subroutine will be activated when the button is clicked and the button handle will be passed into the subroutine as an argument If returnVar is not a valid branch label or subroutine name then the value of returnVar is available to be read when the program is halted at an input var statement The value will be placed into the specified variable An example appears below corner This parameter must be one of the following UL UR LL or LR It specifies which corner of the window acts as an anchor for the button For example if LR is used then the button will be located relative to the lower right
203. he name for value wend here is our data data one hundred 100 two 2 three 3 end 0 end You can also read numeric items read the numbers and their descriptions while desc lt gt end read desch value print desc is the name for valueS length len value wend here is our data data one hundred 100 two 2 three 3 end 0 end RESTORE RESTORE will reset the reading of DATA statements so that the next READ will get information from the first DATA statement in the program or the first DATA statement in a function or subprogram if this is where the RESTORE is executed Example show me my data in all uppercase while string S lt gt end read strings print upperS string wend stringS clear this for next while wend loop now reset the data reading to the beginning restore show me my data in all lowercase while string S lt gt end read strings print lowerS string wend data The Quick Brown Fox Jumped data Over mPa Laz W Do Ry end F 1 end RESTORE branchLabel Optionally you can choose to include a branch label show me my data in all uppercase while string lt gt end read strings print upperS string wend stringS clear this for next while wend loop now reset the data reading to the second part restore partTwo show me my data in all lowercase while string lt gt end read strings print
204. hen backColor word CommandLines 2 print win backcolor backColors end if if words CommandLinesS 3 lt gt then Color words CommandLine 3 print win color Colors end if print win size 5 print win place 10 20 print win boxfilled 100 110 print win flush wait quit close win end To call this program from another program as a TKN or EXE or to run the EXE by using the RUN button in Windows run commandlinetest2 tkn red yellow blue or run commandlinetestl exe red yellow blue the CommandLine variable will contain red yellow blue Numbers and CommandLine The information contained and used in CommandLine can be anything that can be contained in a string If numbers are required then use the VAL function to extract them firstS words CommandLineS 1 firstval val firsts Suggestions for using CommandLine The CommandLine could contain a filename which the program would open and load into a texteditor The CommandLine could contain numbers to be used in calculations As in the examples above it could contain colors that determine the look of a window CONFIRM Please Confirm ES 2 Are you sure you want to QUIT No N CONFIRM string responseVar Description This statement opens a dialog box displaying the contents of string and presenting two buttons marked Yes and No When the selection is made the string yes
205. hes to the keyCheck routine and Inkey contains the information about the key s pressed by the user a simple keycheck program open Press some keys for graphics nsb as draw draw setfocus place 10 20 draw when characterInput keyCheck wait keyCheck draw InkeyS wait See also graphics commands Inkey and Using Virtual Key Contants with Inkey for more details Graphics Commands See also Understanding Syntax how to use literals and variables in commands New for Liberty BASIC 4 scrollbars may be turned on and off and the scroll range may be set See HORIZSCROLLBAR and VERTSCROLLBAR commands below The slider on the scrollbar now opens at the top for vertical scrollbars and at the left for horizontal scrollbars rather than in the middle as they did in previous versions of Liberty BASIC Also new drawing segments can be given names In previous versions of Liberty BASIC segment ID s were numbers assigned by Liberty BASIC For more on using named drawing segments see the FLUSH command below Most of these commands work only with windows of type graphics and with the graphicbox control It should be noted that graphics windows and graphicboxes are intended for drawing graphics It is not advisable to place controls within them since some controls do not work properly when placed in graphicboxes or graphics windows If there is a need for text display within a graphicbox or graphics window use the graphics
206. his option is set Liberty BASIC will check to see if a newer version of the currently loaded file exists and load it into the editor replacing what is there This only happens on activation of the editor meaning that some window other than the Liberty BASIC editor was made active another editor or GUI drawing program perhaps and then the editor is made the active window again by clicking on it or by bringing it to the front in some other fashion pressing Alt Tab for example Why this is useful Some programmers may prefer to use their favorite text editor to write code saving the code when they are ready to try running or debugging it Liberty BASIC will be open on that file so after they save in the other editor and switch to Liberty BASIC with Reload File on Activate the newest saved version of the file is automatically reloaded into Liberty BASIC and all that is needed to run it is to use the Run menu or to press Shift F5 The Liberty BASIC INI file Liberty BASIC uses a file called lbasic4 ini to store preferences Even the application runtime engine uses some of the information in this file if it finds the file on startup Here is a detailed description of its format descriptive comments are not part of the file information editfont courier new 9 editor font printfont courier new 11 printer font preferences true confirm exit of Liberty BASIC false display execution complete notice true put
207. his saves a named bitmap to the specified filename The named bitmap can be obtained either from the LOADBMP command or the GETBMP graphics command The bitmap will be saved to disk in the same resolution as the user s display resolution If the user s display is setup for 32 bit color then the bitmap will be in 32 bit format for instance If a full path isn t given for the saved bitmap it will be saved in the program s DefaultDir Usage gen noma open wait qui clos end erate some graphics and save them to disk inwin Ellipses for graphics as 1 print 1 trapclose quit print 1 down print 1 place 130 130 for x 30 to 230 step 10 print 1 ellipse x 260 x next x print 1 flush print 1 getbmp drawing 1 1 250 250 bmpsave drawing ellipses bmp t e 1 BUTTON Button BUTTON handle ext label returnVar corner x y width height Description This statement adds a button that has a text label to a window created with the OPEN command The width and height parameters are optional Usage The BUTTON statement must be listed before the statement to OPEN the window that will contain it Here is a brief description for each parameter as listed above handle ext The handle must be identical to the handle of the window which will contain the button The button may have an optional unique extension which allows it to receive commands during program execution
208. hr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr A re o ONS ot gt nNnA A UN Su 4 2 3 7 a z nn K D Dn Oe KEN BQ yvy UM I 1 J 2 w n H Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Oo A A As OQ H o rR Din Die OI D 7 Dp to K S K D H CC Cep K OOO GOO uN Den L n k Pi Eb Dh Er Q H H E PA D D up D Dea Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr ot tot te Dr e OOOD se Or Oo O KOK Go Gy Ge D ASN n Description This function returns the arc sine of the number or numeric expression n The return value is expressed in radians Usage print The arc sine of 0 2 is asn 0 2 Tip There are 2 pi radians in a full circle of 360 degrees A formula to convert degrees to radians is radians degrees divided by 57 29577951 Note See also SIN ATN n Description This function returns the arc tangent of the number or numeric expression n The return value is expressed in radians Us
209. iberty BASIC for a long time Itis a utility that allows you to lay out your program windows in a graphical way You can simply click and drag with the mouse to add controls to a window move them and size them GUI stands for Graphical User Interface This interface is all of the controls that appear on a window that allow the user to interact with the program When the look of the window is satisfactory you may save the template for future use You may also choose to produce the code to create this window or choose to produce the code to create the window plus an outline that includes stubs for all of the controls included in the window FreeForm is included in code form as well as in tokenized form You can run the tokenized version from the RUN menu FreeForm is open source software Feel free to modify it to suit your own needs and preferences Many enthusiastic Liberty BASIC programmers have written modified versions of FreeForm over the years and many of these modifications are part of the version of FreeForm that is included with Liberty BASIC Using the Debugger HOW THE DEBUGGER HELPS You can use the debugger when a program doesn t behave the way you expect or when there are errors that prevent it from running You can watch as each line of code is executed to see if the variables contain the correct values The TRACE command is used in conjunction with the debugger It allows you to mark places in code that will cause the debugger to
210. ickness lineThickness colorRed UL 5 5 colorYellow UL 4 colorGreen UL TanlarRluel T mp lredottn bmp bmp yllwbhttn bmp bmp grnbttn bmp hmn bh luebt t n hmn bripou P bmpbutton 1 bmpbutton 1 hrmnhut t oan 1 When the file is ready Liberty BASIC will prompt you to enter a filename in place of the default draw1 tkn in this case _TKN File As EI alle txt AMPMTIME bas ASCII bas A Binary File Example bas Deskto D BITMAP bas My Documents im SC Mu Computer E CHECKBOX bas CIRCLES bes CLOCK2 bas COLLIDES bas colordialog bas colorex bas COLOREXP bas COMBO bas COMBOBOX bas CONSOLE3 bas CONTACT3 bas DIR bas DRAW bas DRAW_R bas DRAW bas Va ea Once the file has been saved to disk you run the TKN file from within Liberty BASIC Pull down Liberty BASIC H G JE E DRIVES bas ELAPSED bas ELLIPSES bas enumfont bas enumwindows bas ERHANDLR bas EI error log example fr3 exit for bas exit while bas EXPONENT bas FACTORIL bas FILE_ID DIZ FILES bas FONTBUG bas the Run menu and select Run TKN File as shown Liberty BASIC v4 0 draw1_bas Bun TKN Die setForLine Ellipse se S h colorRed Yellow colorYell i Thickness lineThickness bmpb SI bmp H colorRed UL 5 5 bmpbutton 1 bmp yllwbttn bmp colorYellow UL 4 bmpbutton 1 bmp grnbt
211. if eof 1 lt gt 0 then quit print input 1 1 goto loop quit close 1 end For most devices unlike disk files one item does not refer a single character but INPUT may return items more than one character in length In most cases use of INPUT handle varName works just as well or better for reading devices Here is another example which shows reading keypresses in the mainwindow accept characters and display them until Enter is pressed text while cS lt gt chr 13 c input 1 print cS if c lt gt chr 13 then text S text cS wend print You typed text end File input directly to an array Previous versions of Liberty BSIC required you to input to a variable then filll an array with the variable Liberty BASIC 3 removes that limitation and allows you to input from a file directly into an array Example input from a file directly into an array open myfile txt for input as handle while EOF handle 0 input handle array total total totaltl wend close handle for i 0 to total print arrayS i next See also INPUTTO h c Line Input Input INPUTTO h c INPUTTO handle delim Description This function reads from the file handle up to the character specified in delim or to the end of the line whichever comes first This is handy for reading files which contain comma tab pipe or other delimited items display each
212. if the mouse is inside that window when the user presses the left mouse button The graphicbox handle MouseX and MouseY variables are passed into the designated subroutine If keyboard input is trapped the graphicbox handle and the value of the key pressed are passed into the designated subroutine See Reading Mouse Events and Keystrokes Whenever a mouse event is trapped Liberty BASIC places the x and y position of the mouse in the variables MouseX and MouseY The values represent the number of pixels in x and y the mouse was from the upper left corner of the graphic window display pane Whenever a keyboard event is trapped Liberty BASIC places the value of the key s pressed into the special variable Inkey See Using Inkey If the expression print handle when event is used with no branch label designation then trapping for that event is discontinued It can however be reinstated at any time Example of turning off the leftButtonDown event handler print handle when leftButtonDown Events that can be trapped leftButtonDown the left mouse button is now down leftButtonUp the left mouse button has been released leftButtonMove the mouse moved while the left button is down leftButtonDouble the left button has been double clicked rightButtonDown the right mouse button is now down rightButtonUp the right mouse button has been released rightButtonMove the mouse moved while the right button is down rightButtonDouble the
213. ight in the font command Ifthe width parameter is set to 0 the default width for that font face and height will be used Here are some examples that set font size by point and by pixel specify just a point size with a single size parameter print fontExample font Arial 14 specify a width and height in pixels with two size parameters print fontExample font Arial 8 15 specify a height for compa tibility with earlier versions of Liberty BASIC print fontExample font Arial 0 15 and let Windows pick the width Attributes Any or all of these attributes modifiers can be added italic bold strikeout and underscore go nuts and add ALL the modifiers print fontExample font arial 8 italic bold strikeout underscore Built in Dialogs Liberty BASIC has several built in dialogs that allow the program s user to make choices or to enter a small amount of text They are as follows COLORDIALOG This dialog allows the user to select a color from the Windows Common Color Dialog CONFIRM This dialog gives the user a short message and allows him to choose yes or no in response by clicking the YES or NO button to dismiss the dialog It is often used to ask a user if he would like to save his work before exiting a program FILEDIALOG This dialog activates the Windows Common File Dialog that allows a user to select a disk filename to open or save FONTDIALOG This dialog allows a user to
214. ill simply be displayed on the control See the topics for individual controls for control specific documentation nomainwin button win bttn Hello hello UL 10 70 checkbox win cbox Goodbye quit quit 10 160 120 24 menu win amp Main amp Show doShow amp Hide doHide E amp xit quit open Show and Hide for window as win wait quit close win end doShow win bttn win cbox wait doHide win bttn win cbox wait lShow Show Hide Hide hello wait Trapping the Close Event It is important for Liberty BASIC program windows to trap the close event Then when a user tries to close a window program flow is directed to an event handler that the program specifies At that place the program can ask for verification that the window should be closed and or perform some sort of cleanup close files write ini data set a flag that the window is open or closed etc There may be a menu item or button that a user can click to close the window but the user might also click the X closing button or the system close button and that is the event trapped by the trapclose statement The trapclose command works with all window types Here is the format for trapclose print myWindow trapclose branchLabel print myWindow trapclose sublabel myWindow trapclose branchLabel This will tell Liberty BASIC to use the code at branchLabel as an event handler for the window
215. in the mainwindow 1 flush 1 trapclose quit wait check shift 4 ctrl 8 alt 16 a asc leftS Inkey 1 if len Inkey gt 1 then mS Ww if a and shift then m shift if a and ctrl then m mS ctrl if a and alt then m mS alt print Special keys pressed m else print Key pressed Inkey end if wait quit close l end See also Using virtual key constants with Inkey Using Inkey Reading Mouse Events and Keystrokes INP returnedByte INP port Description This function polls the specified machine UO port for its byte value If you will be distributing your application and it uses INP and or OUT to control hardware ports you will need to distribute and install certain files on your user s system For detailed information see Port I O See also OUT port byte INPUT INPUT handle string expression variableName Description This command has several possible forms input var This form causes a program to stop and wait for user to enter data in the program s mainwin and press the Return key It will then assign the data entered to var input enter data var This form will display the string enter data and then stop and wait for user to enter data in the program s mainwin and press Return It will then assign the data entered to var input name var This form will get the next data item from the open file or device using handle named hand
216. indow and the resizehandler is invoked the controls in that window can be resized and positioned using the locate command It is necessary to precede the command with a character for controls such as buttons and textboxes that can accept a new text string or caption See the command lists for individual controls for control specific documentation After this the REFRESH command is used to redraw the entire window move and size controls print handle ext locate x y w h move and size buttons textboxes etc print handle ext locate x yw h In the example above x y wh are standing in for literal values To use variables place them outside the quotation marks and be sure to preserve the blank spaces literals print handle ext locate 12 20 100 24 variables x 12 y 20 w 100 h 24 print handle ext locate x y w Zh See the example program RESIZE BAS REFRESH This command is useful when the RESIZEHANDLER command is used see above After a user resizes a window and the resize handler is invoked the controls in that window may be resized and positioned using the locate command After this the REFRESH command is used to redraw the entire window update the window print handle refresh See the example program RESIZE BAS SETFOCUS Input focus can be set to a control or to a window with this command This means that keyboard input will be directed to the specified control or window Begin
217. ing seek myfile 0 read input the data myfile txts print data in mainwin print New Data is txt close the file close myfile end Random Access Files OPEN filename FOR RANDOM AS handle LEN n To access a file in random access mode it must be opened with the OPEN statement When it is no longer needed and before the program ends it must be closed with the CLOSE statement See also Filedialog File Operations Path and Filename PUT FIELD GET GETTRIM Random Access files consist of RECORDS The entire file is divided into many records Each record has the same length The length is specified when the file is opened with the LEN parameter The example below opens a file called members dat and sets the record length to 256 OPEN members dat FOR RANDOM AS 1 LEN 256 Reading and writing to a file opened for random access is done one record at a time A record may be read or written anywhere in the file A record is read with either the GET statement or with the GETTRIM statement A record is written to the file with the PUT statement These statements are explained in more detail below FIELD Statement Each record is subdivided into fields each with a given length The FIELD statement must be included after the OPEN statement to set up the size of each of the fields Each field is designated by a variable name and given a specified length When the lengths of all fields are added together th
218. int 1 text Checkbox is t wait quit close 1 end In the above code Liberty BASIC opens a small window with a checkbox a textbox and a few buttons After that it stops at the WAIT statement just after the branch label waitHere At this time if the user clicks one of the buttons or the checkbox Liberty BASIC can handle the event and go to the appropriate branch label The code can be observed in action by stepping through it with the debugger Subroutine Event Handlers button main accept Accept userAcceptsSub UL 10 10 This adds a button to the window main labeled Accept When the program is run and the user clicks on this button then execution calls the subroutine userAcceptsSub passing the handle of the button as an argument to the subroutine Liberty BASIC 3 only lets you handle events using branch labels This works well for simple programs but it since code executed after a branch label does not know how it was called each control must have its own branch labels for each event it can trigger Now with LB4 you can specify a subroutine to handle events and when an event gets triggered the subroutine is called and information about the origins of that event such as the handle of the control that triggered the event get passed into the subroutine The old way See in this example how each listbox needs its own handler for selection gosub loadData listbox win pets pet selectPet 10 10 140
219. int txtWin The fox jumped over the dog print txtWin trapclose quit wait quit close txtWin end The OPEN statement is used to open a window The window can receive commands via the PRINT statement and it is closed with the CLOSE statement The second print statement above starts with an exclamation point This is required when printing commands to text controls in order to tell Liberty BASIC to execute a command instead of printing the text to the control New to Liberty BASIC 3 it is no longer necessary to use the PRINT statement when issuing commands to a window or control The word print is optional as is the comma after the window or control handle The following version of the code above functions identically and requires less typing open My Text Window for text as txtWin txtWin The fox jumped over the dog txtWin trapclose quit wait quit close txtWin end Printing trapclose quit to the window tells it to use the event handler code at quit to decide what action to take when the user tries to close the window This is important Each window OPENed should also have a handler set up for trapping the close event Windows can have other user interface elements Here is an example statictext dialog static What is your name 10 10 100 20 textbox dialog tbox 10 30 100 20 button dialog accept Accept gotIt UL 10 55 open Name getter for dialog as dialog print dial
220. inted right away Usage sample program using LPRINT and DUMP open c autoexec bat for input as source while eof source 0 line input source texts print each line lprint texts wend close source dump force the print job end Note see also LPRINT EOF h Description This function is used to determine when reading from a sequential file whether the end of the file has been reached If so 1 is returned otherwise 0 is returned Usage open testfile for input as 1 if eof 1 lt 0 then skipIt loop input 1 text print texts if eof 1 0 then loop skipIt close 1 END Description This statement is used to immediately terminate execution of a program If any files or devices are still open See CLOSE when execution is terminated then Liberty BASIC will close them and present a dialog expressing this fact It is good programming practice to close files and devices before terminating execution Note The STOP statement is functionally identical to END and is interchangable Also make sure that when a program is finished running that it terminates properly with an END statement Otherwise the program s windows may all be closed giving the illusion that it has stopped running but it will still be resident in memory and may still consume processor resources Usage print Preliminary Tests Complete askAgain input Would you like to continue Y N yesOrNo s yesOrN
221. ion This command changes the titlebar of the main window It doesn t change the title of any other window Here s a real small clock program ittyclok loop if timeS lt gt timeS then timeS timeS titlebar times end if scan goto loop TRACE n TRACE number Description This statement sets the trace level for its application program This is only effective if the program is run using the Debug menu selection instead of RUN If Runis used then any TRACE statements are ignored It allows you to mark places in code that will cause the debugger to change modes between step animate and run This allows you to use the run button to debug a program and when it hits a TRACE 2 command in the code it will automatically drop down into step mode See Using the Debugger There are three trace levels 0 1 and 2 Here are the effects of these levels 0 full speed no trace or RUN 1 animated trace or ANIMATE logs variables and highlights current line 2 single step mode or STEP requires programmer to click STEP button to continue to next line of code to execute logs variables When any Liberty BASIC program first starts under Debug mode the trace level is always initially 2 STEP You can then click on any of the buttons to determine what mode to continue in When a TRACE statement is encountered the trace level is set accordingly but you can recover from this new trace level by clicking again on the desire
222. ion of the code above functions identically and requires less typing open My Text Window for text as txtWin txtWin The fox jumped over the dog txtWin trapclose quit wait quit close txtWin end A Simple Example In Liberty BASIC windows are treated like files and anything in this class is refered to as a BASIC Device The OPEN statement is used to OPEN a window and the CLOSE statement is used to close it The window is controled with PRINT statements just as a file is controlled by PRINT statements The Print statement may be omitted when sending commands See Sending Commands The commands are sent as strings to the device The following simple example opens a graphics window centers a pen like a Logo turtle and draws a simple spiral When the user attempts to CLOSE the window he is asked to confirm the exit and if he agrees the window is closed button graph open Example for graphics as graph print up print home print down for index to 30 print graph go index print graph turn 118 next index print graph flush inputLoop input b goto inputLoop exit confirm Close Window answerS if answer close graph end no then inputLoop Exit exit LR 35 20 window will have a button open graphics window make sure pen is up center the pen make sure pen is down draw 30 spiral segments go foreward index places turn 118 de
223. kenized File Preparing for distribution You can share or sell programs that you write in Liberty BASIC No fee or royalty payment is necessary The only requirements are a That you limit the files that you distribute to the list below These files can be found in the directory in which you have installed Liberty BASIC If you cannot see all of these files in My Computer or Windows Explorer it is likely that your folder options are configured to hide system files Go to the TOOLS menu of Explorer and choose FOLDER OPTIONS Click the VIEW tab and look for the option to Show all files in the Hidden Files section Be sure that this option is checked Here is a list of the files vbas3l1lw sll vgui3lw sll voflr3liw sll vthk31lw dll vtk1631w dll vtk3231w dl1l vvm31lw d1l vvmt31lw dll run400 exe b You must rename a copy of RUN400 EXE to your liking This is recommended Try to create a unique name so that it will be unlikely for any File Manager associations to conflict If you rename RUN400 EXE to MYPROG EXE then renaming your TKN file to MYPROG TKN will cause it to be automatically run when the runtime engine starts c You can also replace the icon for RUN400 EXE with one of your own design Use the icon editor from the Setup menu in the Liberty BASIC editor This step is optional Icons for use with the Liberty BASIC runtime engine can contain only 16 colors Important Make sure that when your program is finished running t
224. king or dragging with the mouse Once selected an item usually turns a different color or becomes outlined Icon An icon is a tiny clickable picture used to provide a startup link to a program or a file Identifier A lexical unit that names a language object such as a variable array record label or procedure Literal A hard coded text or numeric value that is written in programming source code Maximize Button The button in the middle of three button at the right end of the titlebar which enlarges the window to its greatest possible size MB Abbreviation for megabyte One MB is approximately one million bytes Menu A list of items from which you may choose Menu Bar The bar located under the titlebar that list the available menus Minimize Button A button located at the right side of the titlebar that you can click to reduce a window to a task button on the taskbar Monitor The computer s visual output device similar to a television Mouse A device you can move to select items on the computer screen On the screen you will see a mouse cursor which you can move by moving the mouse Multitasking The ability of an operating system to run more than one program at one time My Computer A program the obvious quick way to the files and folders on your computer Operating System OS The software responsible for the direct control and management of hardware and basic system operations Parallel Port A connect
225. lap the displayed area of the groupbox will be nested inside the groupbox This is particularly useful for radiobuttons It is possible for only one radiobutton in a radio set to be set at one time The groupbox allows the window to have multiple radio sets of radiobuttons Only one of all radiobuttons in a groupbox will be allowed to be in a set state Click on one to set it and all the others will be reset handle ext This must be the same handle as the window that contains the groupbox ext is an optional unique extension unique to the groupbox label This is the caption or text label that appears on the groupbox x y These parameters determine where to position the groupbox relative to the upper left corner of the window workspace wide high These parameters specify how wide and high the groupbox will be in pixels For information on creating controls with different background colors see Colors and the Graphical User Interface print handle ext a string This changes the text displayed on the control This command sets the contents the visible label to be a string The handle must be of form handle ext that includes a unique extension so that commands can be printed to the control print handle ext locate x y width height This repositions the control in its window This only works if the control is placed inside window of type window The control will not update its size and location until a REFRESH com
226. lared with the GLOBAL statement are available in the main program and in subroutines and functions Arrays structs and handles of files DLLs and windows are global to a Liberty BASIC program and visible inside a subroutine without needing to be passed in Special global status is given to certain default variables used for sizing positioning and coloring windows and controls These include variables WindowWidth WindowHeight UpperLeftx UpperLeftY ForegroundColor BackgroundColor ListboxColor TextboxColor ComboboxColor TexteditorColor The value of these variables as well as DefaultDir and com can be seen and modified in any subroutine function Branch Labels Branch labels are locally scoped Code inside a subroutine cannot see branch labels outside the subroutine and code outside a subroutine cannot see branch labels inside any subroutine Ending a Subroutine The sub definition must end with the expression end sub Executing Subroutines Be sure that a program doesn t accidentally flow into a subroutine A subroutine should only execute when it is called by command in the program wrong for i 1 to 10 do some stuff next i Sub MySub paraml param2 do some stuff End Sub correct for i 1 to 10 do some stuff next i WAIT Sub MySub paraml param2 do some stuff End Sub Example Usage copy two files into one fileOneS first txt fileTwo second txt combinedS together txt c
227. le and assign the data to var If no device or file exists that uses the handle named handle then INPUT returns an error input name varl var2 This form causes the next two data items to be fetched and assigned to var1 and var2 line input name vars The LINE INPUT statement will read from the file ignoring commas in the input stream and completing the data item only at the next carriage return or at the end of file This is useful for reading text with embedded commas Usage Display a text file filedialog Open txt filenames open filenameS for input as text loop if eof text lt gt 0 then quit input text items print items goto loop quit close text print Done end Arrays In earlier versions of Liberty BASIC INPUT could not be used to input data directly into arrays only into the simpler variables For Liberty BASIC 3 that limitation no longer exists It is now possible to use Input and Line Input to fill arrays directly To input directly to an array input arrayS x It is also possible to use this method input array x stringS stuff i Question Mark Most versions of Microsoft BASIC implement INPUT to automatically place a question mark on the display in front of the cursor when the user is prompted for information input Pleas nter the upper limit limit produces Please enter the upper limit Liberty BASIC makes the appearance of a question mark optional
228. le filenames ending in bmp are bitmaps Folders do not typically have extensions The names below with extensions indicate files while the names without extensions indicate folders Here are some examples of relative paths smiley bmp go up one level to access the file images redbox bmp go up one level to access the file in the images folder customer txt go up two levels to access the file data names dat go up two levels to access the file in the data folder Hard coding Path and Filename The phrase hard coding when referring to path and filename information indicates that the pathname specified in the progarm code contains the entire file specification including the drive letter and all folder information as well as the filename Ifa program is meant for use by the programmer alone on a single computer this method works as long as no changes are made to the directory structure When any changes are made to the directory structure or filename the program code must be changed as well Caveat It is very unlikely that other users of a program will have the same directory structure on their computers as the programmer who writes the code For this reason it is best to use one of the other path naming options listed above that does not depend upon all users having the same directory structure on their computers Filenames Used in Code Some commands that use path and filename specifications are LOADBMP OPEN P
229. le pointer to the location specified Use the LOC handle function to retrieve the current position of the file pointer The current position of the file pointer is used when reading or writing data to a binary file Data is read from the file with the INPUT statement Data is written to the file with the PRINT statement Binary mode never writes line delimiters when printing to the file Line delimiters include carriage returns which are chr 13 and line feeds which are chr 10 Usage binary file access open myfile ext for binary as handle seek to file position seek handle fpos get the current file position fpos loc handle write a byte to the file print handle chr 143 read the data at the current location input myfile txts Example Program binary file example open myfile bin for binary as myfile txt I like programming with Liberty BASIC print Original data in file is txts write some data to the file print myfile txt retrieve the position of the file pointer nowPos LOC myfile move the filepointer nowPos nowPos 14 seek myfile nowPos read the data at the current location input myfile txts print txt in mainwin print Data at nowPos is txt mov the filepointer seek myfile 2 write some data to the middle of the file print myfile love print str loc myfile 2 bytes written move the file pointer to the beginn
230. les on your user s system For detailed information see Port I O See also INP port Platform Description This variable holds the string Windows When programming with Liberty BASIC for OS 2 the same variable holds OS 2 This is useful so that you can take advantage of whatever differences there are between the two platforms and between the versions of Liberty BASIC Note see also Version PLAYMIDI PLAYMIDI filename length Description This plays a MIDI sound from a file on disk as specified in filename The length variable will hold the length of the MIDI file not in seconds You can only play one file at a time Periodically you will need to use the MIDIPOS function to see if you ve reached the end of the music Finally use the STOPMIDI command to close the music file before you can play a different one Usage the playmidi command returns the length of the midi in the variable howLong playmidi c somedir mymusic midi howLong timer 1000 checkPlay wait checkPlay if howLong midipos then musicEnded wait musicEnded stopmidi timer 0 wait See also STOPMIDI MIDIPOS PLAYWAVE PLAYWAVE filename mode Description This plays a wav sound from a file on disk as specified in filename If mode is specified it must be one of the modes described below sync orsynch wait for the wave file to finish playing the default async orasynch don t wait for the
231. lick the X button in the top right corner of a window to close that program When you close a program it is no longer active Command The programming term for an instruction to the computer Computer Program A computer program tells a computer what the computer should do It is a sequence of instructions to be executed in order A computer program consists of a set of instructions that the computer understands Controls Tools that appear on the user interface that let the user respond to the program enter data and view images and other kinds of output data Buttons textboxes and menus are examples of controls Database An organized collection of information Data Data is information There are many types of data including sound graphics and text Most data on a computer is stored in files on the hard disk which are made up of bytes Computer programs are also data though many people may use the word data to mean information stored on the computer by the end user Data File A file that consists of data that has been created in a program such as a text file typed in Notepad Default The standard settings in a program Desktop The opening screen in Windows that contains a few objects the startbutton and the taskbar This is what you see on your computer screen when you have no windows open It may be a solid color or it may be graphics On the desktop there will be icons including one called My Computer and one ca
232. list of choices but there isn t much room on the window to display a list A GRAPHICBOxX is a box that displays graphics such as bitmap images or drawn objects like circles and lines or even text A graphicbox is used to give the user a graphic display such as showing a bitmap image drawing a graph or chart or simply to add visual interest to a program GroupBox M CheckBox RadioButton C RadioButton 2 A GROUPBOX consists of a label and a box The box can contain other controls so that they may be grouped for easy identification Radiobuttons within a groupbox function as a set To have multiple sets of radiobuttons in a window each set must be placed in its own groupbox First em Second em Third Wem Fourth Hem A LISTBOX is a form of list It appears as a list of items in a box on the window The user may make a choice by clicking on an item in the list with the mouse If there are more items in the list than there is room in the listbox the listbox will automatically add scrollbars A listbox is a good choice when it is necessary to give the user a list of choices Window Title Menu Title Edit Menu Item ST A MENU is a dropdown list of user commands that appears on a bar below the titlebar of a window The user clicks on an item contained in the dropdown list to give the window a command A POPUPMENU is a dropdown list of user commands that appears where the mouse is located when the popupmenu co
233. lled The Recycle Bin Dialog Box A special kind of window that asks you a question or presents controls that you can choose from Directory The term folder has largely replaced this term They mean the same thing Disk The permanent storage area for your programs and documents Disk Drive Hardware capable of reading and writing data stored on a disk Document Any data you create with a program DPI Dots Per Inch a unit of measure describing printer resolution Double Click Pressing and releasing the left mouse button two times in quick succession without moving the mouse between clicks Drag mouse Move the pointer on an item hold down the left button slide the pointer to a new location and release the button Drive Any data storage device This includes your CD ROM drive floppy disk drive and hard disk drive Event An activity that occurs during an application s execution The user normally triggers many events such as keypresses mouse clicks or mouse movements The Windows operating environment can also trigger events such as timer clicks and data transferred from other running programs Event Driven Programming The process of writing programs that respond to triggered events as opposed to older text based programs that were sequential in nature and followed a predetermined flow Events can come from many sources and your program must know which events to respond to and which to ignore Explorer The
234. llows one line of code to be split over several lines of text in the editor For example open user32 for dll as u calldll Zu GetWindowRect hMain as long Rect as struct result as long close u A line can get long and difficult to read Consider the following equivalent Open user32 For DLL As u CallDLL u GetWindowRect hMain As long Rect As struct result As long Close u When the line is broken up with the _ character the code is more readable The NOMAINWIN command When a Liberty BASIC program is run a simple text window called the mainwin appears It can be used to display text and to ask the user for input To suppress the mainwin a nomainwin statement is used nomainwin don t open a mainwin menu draw Draw Draw now drawNow open No man s land er nomainwin for graphics as draw print draw trapclose quit wait drawNow print draw cls home down north for x 1 to 100 print draw turn 122 go strS x 2 next x print draw flush wait quit confirm Do you want to quit Buttons quits if quitS no then wait close draw end The mainwin can be used when a program is under development If a program locks up or crashes it can still be closed by clsoing the mainwin It is important that a program have trapclose handlers for all of its windows when the nomainwin command is used otherwise the program may still be running with no way to close it All pro
235. loop wait arrowClicked notice The arrow button was clicked Goodbye close main end An example that uses a subroutine button handler bmpbutton main arrow bmp arrwbttn bmp arrowClicked UL 10 10 open Button Example for window as main loop wait sub arrowClicked bttnHandles notice bttnHandle was clicked Goodbye close main end end sub An example that retrieves a value with an input statement bmpbutton main arrow bmp arrwbttn bmp yes UL 10 10 bmpbutton main button2 bmp bluebttn bmp no UL 70 10 open Use Input Example for window as main main trapclose quit loop input answers if answer yes then notice You clicked Okay if answerS no then notice You clicked Cancel goto loop quit close main end BMPBUTTON COMMANDS print handle ext bitmap bitmapname This command sets the bitmap displayed on the button to be a that has been loaded previously with the LOADBMP command bitmapname is not the filename of the bitmap but the name given to it by the LOADBMP command Here is a short program that demonstrates the bitmap bmpbutton command bitmap bas demonstrate the bitmap command for bmpbuttons clicking the buttons causes the bitmap images displayed on the buttons to change WindowWidth 248 WindowHeight 175 nomainwin loadbmp arrow bmp arrwbttn bmp loadbmp blue bmp bluebttn bmp bmpbutton main buttonl
236. lor ComboboxColor TexteditorColor DefaultDir Joy1x Joyly Joy1z Joy1button1 Joy1button2 Joy2x Joy2y Joy2z Joy2button1 Joy2button2 and Com now have true global status GLOBALS are specified and used like this define a global string variable global titles title Great Program Special system variables don t need to be declared as global since they have that status automatically BackgroundColors darkgray ForegroundColor darkblue call my subroutine to open a window call openIt wait sub openIt statictext it stext Look Mom 10 10 70 24 textbox it tbox 90 10 200 24 open titleS for window as it print it tbox No hands end sub NOTE Branch labels inside functions and subroutines are not visible to code outside those functions and subroutines If code in the main program tries to access a branch label inside a function or subroutine this will cause get an error Likewise functions and subroutines cannot use branch labels defined outside their scope Passing Arguments into Subroutines and Fuctions by value and BYREF Through Liberty BASIC 3 values can only be passed into a user subroutine or function by value Passing by value is a common term meaning that once a value is passed into a subroutine or function it is just a copy of the passed value and has no relationship to the original value If the value is changed in the called subroutine or function it does not change in th
237. lso specify where to save these files by typing the location into the textbox provided As an example a path to a different hard drive could be specified as protection against hard drive failure Environment Use Syntax Coloring This toggles the editor s syntax coloring mechanism Check this box to see color syntax in the editor or uncheck it to use the system default colors for text Enable Auto Indenting This feature causes the Liberty BASIC editor to copy the level of indenting of the current line to a new line when Enter is pressed It also has some support for back tabbing Add Kill BASIC Appel to all Windows This adds a special menu item to the system menu of each window in the Liberty BASIC environment this menu item can also be found in the Liberty BASIC editor Run menu This feature is useful if your BASIC program will not close or shut down because it allows you to kill any BASIC program started from the Liberty BASIC editor Main window columns rows This sets the default size of the main window for any BASIC program started from the Liberty BASIC editor Source filename extension This specifies the filename extension to use for BASIC programs The default is BAS but the user can change it to something else if desired This is especially useful to prevent filename collision if the programmer also uses other versions of BASIC or other applications that use BAS as a filename extension Reload File on Activate When t
238. m record 1 get cust 1 print nameS print streets print city print states print zips print age close cust end Note See also Random Files PUT FIELD GETTRIM h n GETTRIM handle recordNumber Description The GETTRIM command is exactly like the GET command but when data is retrieved all leading and trailing blank space is removed from all data fields before being committed to variables Note see also GET GOSUB label Description GOSUB causes execution to proceed to the program code following the label using the form GOSUB label The label can be either a traditional line number or a branch label name enclosed in square brackets like this branchLabel Spaces and numbers are not allowed as part of branch label names Here are some valid branch labels mainMenu enterLimits repeatHere Here are some invalid branch labels enter limits mainMenu 1moreTime After execution is transferred to the point of the branch label then each statement will be executed in normal fashion until a RETURN is encountered When this happens execution is transferred back to the statement immediately after the GOSUB The section of code between a GOSUB and its RETURN is known as a subroutine One purpose of a subroutine is to save memory by having only one copy of code that is used many times throughout a program Usage print Do you want to continue gosub yesOrNo if answer S N then quit print W
239. mand is sent to the window See the RESIZE BAS example program print handle ext font facename pointSize This sets the control s font to the specified face and point size If an exact match cannot be found then Liberty BASIC will try to find a close match with size taking precedence over face For more on specifying fonts read How to Specify Fonts Example print handle ext font times new roman 10 print handle ext enable This causes the control to be enabled print handle ext disable This causes the control to be inactive and grayed out print handle ext show This causes the control to be visible print handle ext hide This causes the control to be hidden or invisible HBMP name HBMP string expression Description Returns the Windows handle a numeric value for the bitmap whose name is specified by string expression This is often useful in different kinds of Windows API function calls and for use with third party DLLs Usage loadbmp title bmp titlettt bmp tttHandle hbmp title print tttHandle See also LOADBMP UNLOADBMP HEXDEC value HEXDEC value Description This function returns a numeric decimal from a hexadecimal number expressed in a string Hexadecimal values are represented by digits 0 F The hexadecimal number can be preceded by the characters amp H The hexadecimal string must be enclosed in quote marks Usage print hexdec FF Or
240. mation will not be the same as drawing a frame of animation every one quarter second because in addition to the one quarter second pause time is taken while the code at the branch label is executed Using the TIMER results in much smoother and more accurate timing for animation See how to Add a Mask to sprites Add a Mask The code provided below opens a sprite image and automatically adds a proper mask Ifthe resulting image is correct it can be saved to disk A sprite starts with a drawn image that has a black background like this This image can be opened in the mask maker and a proper mask is added It will look like this while processing Add Masks to Sprites Pil EG Eile If the mask sprite image above is saved it will look like this Here is the code Copy and paste into the Liberty BASIC Editor to run the Add Masks to Sprites program See a Step by Step sprite coding explanation small utility to add masks to the top of sprite images for use in LB3 if val Version lt 3 then notice This program is for LB3 only end end if nomainwin bmpheight 0 bitmap height bmpwidth 0 bitmap width bitmap bitmap file name savefilesS save file name hBitmap 0 handle for loaded bitmap hWindow 0 window handle menu 1 amp File amp Open Sprite openSprite amp Save As SaveAs E amp xit quit open Add Masks to Sprites for graphics fs nsb as 1 print 1
241. mmand is issued The user clicks on an item contained in the dropdown list to give the window a command RadioButton A RADIOBUTTON is a small round box that can be clicked by the user It has a text label Radiobuttons function in groups When the user clicks a radiobutton that button s circle is filled in and all other radiobuttons are cleared The programmer may set or unset a radiobutton in code also A radiobutton is used when a user must choose only one possibility from a group of possibilities StaticT ext A STATICTEXT is a simple text label used to give information to the user The user cannot interact with a statictext control Text ox A TEXTBOXis a small box that contains text Text can be placed in the textbox by the programmer or the user can type into the textbox A textbox is used to get a small amount of text input from the user or to display a small amount of text evi duor A TEXTEDITOR is a large box with both horizontal and vertical scrollbars Text can be placed in the texteditor by the programmer or the user can type into the texteditor A texteditor is used to get a large amount of text input from the user or to display a large amount of text Controls and Events The commands to create a controls must specify event handlers that are associated with user actions made on those controls clicking double clicking selecting etc There are two ways to set up event handlers A branch label may be specifie
242. ms we ve provided Pull down the File menu and select the Open item as shown To open a program you can also click the button on the toolbar that looks like an open file folder Typical Liberty BASIC programs have a file extension of BAS You can choose the default extension you prefer in the Setup Menu Liberty BASIC 4 0 C Program Files Liberty BASIC v4 0 welcome bas c second alpha test version This means that some tes will be added before our final release It that you should keep frequent backup copies of when developing with LB4 just in case is an alpha version we have two goals ARE BUGS in this software guaranteed Please let pw when you find them Please email them to ys libertybasic com and try to be as complete as ole in your description Include some code and tion of the error log file if appropriate Oh and did I say THANKS Some of the ideas in this release are new and probably novel in some ways If they feel weird or wrong I don t mind hearing it If you can think of any way to tweak or improve these ideas give me a shout I may You will see a dialog box similar to the one displayed below Here you will find a list of files that you can load These are text files containing our example BASIC programs Select the item named draw1 bas and click on OK Open a bas Fie Sj BOXES bar CONTACT 3 bas BUTTONS bar DIR ba DRAW_Ribas DRAWX bas DRIVES bas ELAPSED bas Liber
243. n This function returns the length in characters of string which can be any valid string expression Usage prompt What is your name yourNameS print Your name is len yourName letters long LEFT string number Description This function returns from string the specified number of characters starting from the left If string is hello there and number is 5 then hello is the result Usage retry input Pleas nter a sentence gt sentences if sentenceS then retry for i 1 to len sentence print left sentenceS i next i Produces Please enter a sentence gt That s all folks T Th Tha That That That s That s __ That s a That s al That s all That s all_ That s all f That s all fo That s all fol That s all folk That s all folks That s all folks Note If number is zero or less then an empty string will be returned If number is greater than or equal to the number of characters in string then string will be returned RIGHT string number Description This function returns a sequence of characters from the right hand side of string using number to determine how many characters to return If number is 0 then an empty string is returned If number is greater than or equal to the number of characters in string then string will itself be returned Usage print right I m right handed 12 Produces right handed And print right hello world
244. n PrintCopies will contain the number of copies chosen by the user in the printerdialog and the program must print these copies in a loop An example follows Usage choose a file to print filedialog Print a BAS file bas fileToPrints if fileToPrint S lt gt then printerdialog print PrinterNameS is PrinterNames print PrintCopies is PrintCopies print PrintCollate is PrintCollate print PrinterFontS is PrinterFonts if PrinterName lt gt then open fileToPrintS for input as readMe while not eof readMe line input readMe lines lprint lines wend close readMe dump end if end if end Multiple Copies txt Some text to print printerdialog for i 1 to PrintCopies lprint txt dump next i PrinterFont PrinterFont fontSpec Description Liberty BASIC 4 now lets you set the font used for LPRINTing text to the printer The format used for specifying the font is the same as for specifying the font in a graphics window See also How to Specify Fonts LPRINT set a courier 10 italic font PrinterFont courier_new 10 italic The last font set before a page is printed is used for all the text on that page Usage show the current printer fonts print PrinterFont lprint This text will appear in PrinterFont dump set a courier 10 italic font PrinterFont courier new 10 italic lprint This text will appear in PrinterFont dump PROMPT Search on which D
245. n doesn t return a value boolean true false expression See also CALLDLL STRUCT Passing strings into API DLL calls Liberty BASIC provides two ways to pass strings as parameters into API DLL calls By default when passing a string as a parameter Liberty BASIC copies the string and adds an ASCII zero to the end of the copy This ASCII zero is called a null terminator Most Windows API calls expect this kind of zero terminated string This technique provides a copy of the original string to be passed to the API function If the function then modifies that string directly as in the kernel API function GetProfileString and a few others then the Liberty BASIC application calling the function cannot access the modified string because only the copy is modified The way to fix this is for the code to include the ASCII zero onto the end of the string that will be used as a parameter in the API call Liberty BASIC checks for the ASCII zero and if it finds it passes the memory address of original string and does not make a copy This is only necessary if an application passes a string expecting to get it back modified by the API or DLL function called Here is a code segment to get printer info using the GetProfileString API call getpstr bas Get information using the GetProfileString API call open kernel32 d1l1 for dll as kernel Notice that no ASCII zero characters are added to these strings because the program will not need to read a
246. n is to resume then the timer is restarted with a TIMER ms BranchLabel command A SIMPLE PAUSE SUBROUTINE On a fast computer the frames of animation may run too quickly to be useful It is easy to code a simple pause between frames of animation The following little subroutine called Pause requires a parameter for the number of milliseconds to pause between frames There are 1 000 milliseconds in one second A half second pause requires the mil parameter to be 500 A one quarter second pause requires a mil parameter of 250 and a one tenth of a second pause uses a mil parameter of 100 sub Pause mil t times milliseconds while time milliseconds lt tt mil wend end sub This code will activate a one tenth of a second pause between frames when used after each DRAWSPRITES command call Pause 100 A processing loop for a sprite animation with pauses between frames might look like this loop scan call Pause 100 print w g setfocus when characterInput quit print w g when leftButtonDown left print w g when rightButtonDown right gosub drawFrame goto loop TIMER VS PAUSE The TIMER causes a branch label to be executed at a set interval which is measured in milliseconds Setting this interval to 250 for example will cause the branch label to be executed each one quarter second A PAUSE is just that It causes the action to pause for the set interval Pausing for one quarter second BETWEEN frames of ani
247. n mainwin TAN n tangent of n Text window type Text Commands a detailed summary of text window commands in Liberty BASIC TEXTBOX add a textbox entryfield to a window TextboxColor sets or returns textbox color TEXTEDITOR add a texteditor widget to a window TexteditorColor sets or returns texteditor color TIME returns current time as string TIMER manage a Windows timer TITLEBAR sets the title bar of the main window TRACE n sets debug trace level to n Itrapclose text command to trap closing of text window trapclose trap closing of window TRIM s returns s without leading trailing spaces turn graphics command to reset drawing direction TXCOUNT handle gets number of bytes in serial communications queue ULONG data type for calldll and structs UNLOADBMP unloads a bitmap from memory up graphics command to lift pen UPPER s s converted to all uppercase USHORT data type for calldll and structs USING performs numeric formatting UpperLeftX specifies the x part of the position where the next window will open UpperLeftY specifies the y part of the position where the next window will open VAL s returns numeric equivalent of s Version special variable containing LB version info Void data type for CALLDLL WAIT stop and wait for user interaction when graphics command to trap mouse and keyboard events WHILE WEND performs looping action Window window type WindowWidth specifies the width of the next
248. nager for output Liberty BASIC 4 now scales graphics when sending them to a printer Until version 4 0 Liberty BASIC printed the contents of graphics windows at 1 1 which resulted in tiny printed versions of what was visible on the screen Now it will scale the graphics based on the size they appear on the display monitor and the resolution of the printed page Only TrueType fonts scale when printing Bitmap fonts stay at their native resolution when printing When printing a graphics window which has had the fill command applied it will cause an entire printed page to be filled with that color which may be highly undesireable When graphics will be sent to the printer consider using the boxfilled command rather than the fill command so that the absolute size of the filled area can be specified print handle redraw or print handle redraw idNum or print handle redraw segmentName This command causes the window to redraw all flushed drawn segments or a specific drawn segment The specific segment can be identified by the ID number assigned by Liberty BASIC and retrieved with a SEGMENT command or it can be a segment name assigned by the program when the FLUSH command is issued Any deleted segments will not be redrawn see DELSEGMENT Any items drawn since the last flush will not be redrawn either and will be lost print handle rule rulename or print handle rule _R2 NOTXORPEN This command specifies whether dr
249. nal test There is one block in the example above and it is executed if qtySubdirs 0 It is also possible to use the ELSE keyword as well with blocks if qtySubdirs 0 then print None else print Count of subdirectories qtySubdirs end if This type of coding is easy to read and understand There are two blocks in this example One is executed if qtySubdirs 0 and one is executed if qtySubdirs is not equal to 0 Only one of the two blocks will be executed never both as a result of the same test These conditional blocks can be nested inside each other if verbose 1 then if qtySubdirs 0 then print None else print Count of subdirectories qtySubdirs end if end if In the example above if the verbose flag is set to 1 true then display something or else skip the display code entirely Comparison to QBasic Conditional Statements Liberty BASIC supports conditional blocks very similar to those in QBasic The format looks like the following silly example if blah blah blah then some code here end if or like if blah blah blah then some code here else some other code her end if Blocks may be nested if sis boom bah then if blah blah blah then some code here end if else some other code her end if The elseif keyword is not supported Here is an example using elseif QBasic QBasic only if sis boom bah then print Yippie elseif la dee da then print So what
250. nd landscape DEFAULT BACKGROUND If no BACKGROUND command is issued a plain white background will be used CHANGING THE BACKGROUND The background can be changed at any time It may be changed to a bitmap that has been loaded into memory with the LOADBMP command or with the GETBMP command It is also possible to draw on the screen to create a new GETBMP bitmap during program execution and then designate it to be the background To set a new bitmap called mountains as the background just use the BACKGROUND command after loading the bitmap loadbmp mountains mts bmp print w g background mountains IMPORTANT The background will not appear in the graphicbox or graphics window until the DRAWSPRITES command is given This command updates the display Even if there are no sprites in use or if no sprites are visible the DRAWSPRITES command must be issued to display the background onscreen Whenever the BACKGROUND command is issued it must be followed by a DRAWSPRITES command to cause it to show on the screen SCROLLING THE BACKGROUND The background image can be moved within the graphicbox or graphics window with the BACKGROUNDXY command The x y location specified on the background image will be placed at point 0 0 of the graphicbox or graphics window Positive and negative numbers are acceptable for the x and y locations print handle ext backgroundxy 25 20 OR x 25 y 20 print handle ext backgroundxy x y
251. ndows programming Programming Windows The Definitive Guide to the Win32 API by Charles Petzold Microsoft Press ISBN 157231995X For a catalog of Windows API calls and their function Windows 2000 API SuperBible by Richard J Simon Sams ISBN 0672319330 Microsoft Developer s Network Library http msdn microsoft com library What are APIs DLLs API stands for Application Programming Interface Windows APIs are the function calls that are the fundamental building blocks of Windows programming Although the term API actually refers to the complete set of function calls it is also often applied to just a single defined function call of the entire API So it is often said made an API call or I want my program to call an API that does such and such Each and every time Windows is loaded or whenever Windows programs are run many API calls are made There are API calls that manage memory create and destroy windows read keyboard and mouse actions draw graphics and much more Liberty BASIC makes many of these API calls behind the scenes in programs However in the context of the BASIC language it would be a tall order and largely unnecessary to create BASIC like statements and functions to implement every Windows API call So for those who already have a working knowledge and for those willing to study and learn about such things Liberty BASIC has implemented a way to call most Windows APIs A complete referen
252. ner of the window acts as an anchor for the button For example if LR is used then the button will be located relative to the lower right corner If the window size is changed during execution of the program the button will always appear at the same position relative to the corner specified as the anchor UL upper left UR upper right LL lower left LR lower right posx posy These parameters set the location for the button relative to the anchor corner posx and posy are expressed in pixels Anchor values of less than one may also be used for posx and posy For example if the anchor corner is UL posx is 9 and posy is 9 then the button will be positioned 9 10ths of the distance of the window in both x and y from the upper left corner This method of positioning buttons places them in positions that are relative to the size of the window rather than anchoring them to a specified corner width height These optional parameters specify how wide and high the button will be measured in pixels If these parameters are not used in the BUTTON statement then Liberty BASIC will set the size of the button to be large enough to display the text label specified Detecting Button Presses Button presses are read and acted upon when a SCAN statement is issued If SCAN is not used then program execution must be halted at an INPUT or WAIT statement in order for a button press to be read and acted upon This example uses a branch label b
253. ng Literals and Variables GLOBAL LITERALS A literal value is hard coded into a program Here are two literals printed to the mainwin The first is anumber The second is a string of text characters print 57 print Hello World produces Dt Hello World VARIABLES A variable is a name used in the code that represents a string or numeric value The value assigned to the variable name may change as the program runs The program can always access the current value of the variable by refering to its name In this example a value of 3 is assigned to a variable called myNumber myNumber 3 print myNumber produces 3 If a different value is later assigned to the variable called myNumber myNumber 17 print myNumber produces 17 In Liberty BASIC variables are either string or numeric A variable name can start with any letter and it can contain both letters and numerals as well as dots for example user firstname There is no practical limit to the length of a variable name The variable names are uppercase and lowercase sensitive so these are not the same variable supercalifragilisticexpialadocious superCaliFragilisticExpialaDocious As in most versions of BASIC string variable names end in a character for example boast String variables can contain 2 million characters The boast above is correct In Liberty BASIC string variables can be huge containing as many as 2 million characters Unlike som
254. ns that have data sets of unknown size If you dimension arrays that are extra large to make sure you can hold data but only have a small set of data then all the space you reserved is wasted This hurts performance because memory is set aside for the number of elements in the DIM statement Usage dim cust 10 dimension the array now we know there are 510 customers on file redim cust 510 now read in the customer records REM REM comment Description The REM statement is used to place comments inside code to clearly explain the purpose of each section of code This is useful to both the programmer who writes the code or to anyone who might later need to modify the program Use REM statements liberally There is a shorthand way of using REM which is to use the apostrophe character in place of the word REM This is cleaner to look at but you can use whichever you prefer Unlike other BASIC statements with REM you cannot add another statement after it on the same line using a colon to separate the statements The rest of the line becomes part of the REM statement Usage rem let s pretend that this is a comment for the next line print The mean average is meanAverage Or let s pretend that this is a comment for the next line print The strength of the quake was magnitude This doesn t work rem thank the user print Thank you for using Super Stats even the print statement becomes part of the R
255. ntained within the same groupbox act as a radio set Clicking setting a radiobutton within one groupbox has no effect on radiobuttons that are placed within other groupboxes See the demo below handle ext This specifies handle for this control The handle part must be the same as the handle of the window that contains the radiobutton and the ext part names the radiobutton uniquely in the window label This specifies the visible text of the radiobutton setHandler This is the branch label or subroutine executed by the program when the user sets the radiobutton by clicking on it See also Controls and Events resetHandler This is the branch label or subroutine executed when the user resets the radiobutton by clicking on it this doesn t actually do anything because radiobuttons can t be reset by clicking on them xOrigin This is the x position of the radiobutton relative to the upper left corner of the window it belongs to yOrigin This is the y position of the radiobutton relative to the upper left corner of the window it belongs to width This is the width of the radiobutton control height This is the height of the radiobutton control Radiobuttons understand these commands print handle ext set This sets the radiobutton print handle ext reset This resets the radiobutton print handle ext value result The result variable will be set to the status of the radiobutton either set or reset
256. ny results out of the call to GetProfileString appName windows keyName device default add an ASCII zero so Liberty BASIC will not pass a copy of result into the API call but the actual contents of results result space 49 chr 0 size 50 49 spaces plus 1 ASCII zero character calldll kernel GetProfileStringA appName as ptr _ keyName as ptr default as ptr _ result as ptr size as long result as long close kernel display the retrieved information up to but not including the terminating ASCII zero print left result instr result chr 0 1 WAIT Caveats There are certain things to be aware of when making API calls and when calling external functions from a DLL including Care must be taken when calling APIs and DLLs because it is possible to cause Windows or Liberty BASIC to become unstable or crash if API and or DLL functions are called incorrectly out of order or with incorrect parameter information Shoptalk Systems does not provide technical support for the Windows API or for third party DLLs that that may be purchased or otherwise obtained We are happy to help you with any questions about Liberty BASIC commands and features that are related to calling APIs and DLLs but we reserve the right to refuse to answer questions about other products including Windows Graphical User Interface The term graphical user interface is often expresse
257. ock end SEEK SEEK handle position Description This command seeks to the desired point in the file for reading or writing in a file opened for BINARY access SEEK sets the file pointer to the location specified Data will be read from or written to the file at the location of the file pointer See also LOC h handle This parameter is the handle of a file opened for binary access position This is the new location for the file pointer Usage open myfile ext for binary as handle seek to file position seek handle fpos SELECT CASE Description SELECT CASE is a construction for evaluating and acting on sets of conditions The syntax for Select Case is SELECT CASE var CASE x basic code goes here CASE y basic code goes here CASE z basic code goes here CASE else basic code goes here END SELECT Details SELECT CASE var defines the beginning of the construct It is followed by the name variable that will be evaluated The variable can be a numeric variable or a string variable or an expression such as a b CASE value following the SELECT CASE statement are individual CASE statements specifying the conditions to evaluate for the selected variable Code after the case statement is executed if that particular case evaluates to TRUE There is no limit to the number of conditions that can be used for evaluation CASE ELSE defines a block of code to be executed if the s
258. of CommandLine See the examples and explanations below Usage In this example the program checks CommandLine for the existence of the word red and if it is there the program executes a color command commandlinetestl bas 1 program to be tokenized to commandlinetestl tkn and used with runtime engine commandlinetestl exe open CommandLine S Test for graphics as win print win trapclose quit convert to lower case for evaluation CommandLineS lower CommandLine if instr CommandLinesS red gt 0 then print win fill red flush end if wait quit close win end To call this program from another program as a TKN or EXE or to run the EXE by using the RUN button in Windows run commandlinetestl tkn red or run commandlinetestl exe red the CommandLineS variable will contain red Multiple parameters in CommandLine The CommandLine may be parsed using the WORD function as well In the following example the program checks for three colors to use in a graphics window commandlinetest2 bas U program to be tokenized to commandlinetest2 tkn and used with runtime engine commandlinetest2 exe open CommandLineS Test for graphics as win print win trapclose quit print win down if words CommandLinesS 1 lt gt then fillColor word CommandLine 1 print win fill f il1Colors end if if words CommandLineS 2 lt gt t
259. og tbox Type your names in here print dialog trapclose quit wait gotIt print dialog tbox contents name notice Hi names wait quit close dialog end The trapclose quit printed to the window in this example does not need an exclamation point in front of it This is because the window is a dialog box and isn t a text widget that displays text PRINTed to it For this reason it accepts PRINTed commands that do not start with the exclamation point The controls added to the window include a statictext a non editable label a textbox an editable field and a pushbutton They are listed before the OPEN statement which opens a dialog window The button statement s declaration includes the branch label Tool The code at gotlt is the button s event handler When the button is clicked it generates an event and gotlt is invoked The code t gotlt prints a command to the textbox asking for its contents to be assigned to the string variable name The program then pops up a notice window displaying a greeting to the user The window in the example above receives a trapclose command This sets a handler for the window s close event to be the branch label designated by trapclose There the window can be closed if appropriate perhaps after querying the user about what to do for example quit confirm Quit Are you sure yesOrNo if yesOrNo yes then quitForSure wait quitForSure close dialo
260. on 30 landerCrashed landerCrashed or terrain xPosition lt gt terrain xPosition 15 end function sub makeSprites open lem for graphics as makeSprites print makeSprites down print makeSprites place 0 31 backColor black boxfilled 640 TON for x 0 to 15 y 1 call drawLEM x y 270 x 22 5 2 black y 2 call drawLEM x y 270 x 22 5 2 darkgray call drawLEM x y 270 x 22 5 1 lightgray call getSprite x next x close makeSprites print lander addsprite lem lemO leml lem2 lem3 lem4 lem5 lem6 lem7 lem8 lem9 lem10 lem11 lem12 lem13 lem1 4 lem15 end sub sub drawLEM xPosition yPosition uncorrectedAngle penSize colors angle uncorrectedAngle print makeSprites north color colors up turn angle print makeSprites place xPosition 304 15 yPosition 1 30 15 print makeSprites size penSize print makeSprites up go 4 down circle 8 print makeSprites turn 75 go 4 turn 180 go 4 print makeSprites turn 30 go 4 turn 180 go 4 burn 255 print makeSprites up turn 160 go 8 print makeSprites down go 4 turn 110 print makeSprites go 8 turn 110 go 4 Ww print makeSprites place xPosition 304 15 yPosition 1 30 15 print makeSprites north up turn angle print makeSprites go 4 turn 125 go 8 down turn 45 EM print makeSprites place xPo
261. on of the window The caption is the text contained on the titlebar of the window purpose When the device is a window the purpose parameter is the window type There are many possibilities for window types and these are explained in Window Types Window and Dialog Commands Graphical User Interface usage open My Cool Program for window nf as main dynamic link library A DLL dynamic link library must be opened before any calls can be made to the functions If the device is a DLL the device parameter will be the disk filename of the DLL enclosed in quotes See CALLDLL purpose The purpose is always for DLL when using OPEN with a dynamic link library usage open c myprog sample dll for DLL as sample or for Windows API calls open user32 for DLL as user32 serial communications port The OPEN statement opens a serial communications port for reading and writing The device parameter is the name of the port enclosed in quotes The syntax looks like this OPEN COMnh baud parity data stop options for random as handle purpose The purpose is always for random when using OPEN to open a communications port See Open Comn Usage To open com port 2 at 9600 baud 8 data bits 1 stop bit and no parity use this line of code open com2 9600 n 8 1 for random as commHandle handle The handle is a unique name given to the device so that it can be accessed by functions in the program Use a descriptive wor
262. ons and subroutines are not visible to code outside those functions and subroutines Likewise functions and subroutines cannot use branch labels defined outside their scope GOTO To continue program execution at a specified branch lable issue a GOTO command See GOTO GOTO startLoop Do not use GOTO to exit a FOR NEXT or WHILE WEND loop prematurely GOSUB To continue program execution at a specifed GOSUB routine issue a GOSUB command The GOSUB routine ends with a RETURN statement that returns program execution to the line of code following the GOSUB command See GOSUB RETURN GOSUB initialize Conditional Statements Conditional statements are implemented with the IF THEN ELSE END IF structure See also Boolean Evaluations IF THEN Select Case IF test expression THEN expression s IF test expression THEN expression s 1 ELSE expression s 2 IF test expression THEN expression s 1 END IF IF test expression THEN expression s 1 ELSE expression s 2 END IF Description The IF THEN statement provides a way to change program flow based on a test expression For example the following line directs program execution to branch label soundAlarm if fuel runs low if fuel lt 5 then soundAlarm Another way to control program flow is to use the IF THEN ELSE statement This extended form of IF THEN adds expressiveness and simplifies coding of some logical decision making software Here is an example of it
263. oop until print print a zero do print b p pt i loop until b 1 print print print L toe am do print b p Dr 1 loop until b 10 examples using loop while print print 1 to 3 a l do while a lt 3 print a a a 1 loop print prin prant 9 to 7 rs do until b 6 print b b b 1 loop print print don t print anything do while c 10 print c c c 1 loop end Drives Description Drives is a system variable It can be used like any other variable Use it in expressions print it perform functions on it etc It is special in that it contains the drive letters for all the drives installed in the computer in use For example print Drivess Will in many cases produce a b c It can be used to provide a way to select a drive like this a simple example illustrating the use of the Drives variable dim letters 25 index 0 while word Drives index 1 lt gt letters index word Drives index 1 index index 1 wend statictext win Double click to pick a drive 10 10 200 20 listbox win list letters selectionMade 10 35 100 150 open Scan drive for dialog as win input r selectionMade close win end DUMP Description This statement forces anything that has been LPRINTed to be sent to the Print Manager to commence printing immediately If DUMP is not issued the LPRINTed text will be printed but it might not be pr
264. opened when the program starts and closed when program execution is completed or the DLL s can be opened just before calling the functions and then closed immediately afterward The following statements functions are available for making API DLL calls OPEN OPEN filename d1l1 for dll as handle This form of OPEN opens a desired DLL so that a program can call functions in it Liberty BASIC 3 has Enhanced DLL handle resolution so that if a program hasn t opened certain default Windows DLLs a reference to a like named handle will still resolve to the desired DLL This will save on code to open and close DLLs The old way still works Ifa program OPENs a DLL then it must be CLOSEd before the program ends If the default handles below are used then a CLOSE command should not be issued Here are the default handles user32 kernel32 gdi32 winmm shell32 comdlg32 comctl32 CALLDLL CALLDLL handle function parml as typel parm2 as type2 result as returnType This statement calls a named function in an OPENed DLL The list of parameters gives information to the function that tells it how to perform its tasks See CallDLL HWND HWND handle This function returns a window handle for the Liberty BASIC handle STRUCT STRUCT name fieldl as typel field2 as type2 The STRUCT statement builds a specified structure that is required when making some kinds of API DLL calls There is an example bel
265. or through which a computer communicates with a peripheral along parallel wires Printers are the most common peripheral to use parallel ports Path The route to a folder or file it consists of the drive name a folder and or subfolder if any and the filename Pixel A picture element or dot that the monitor screen can display to create the image you see Pointer The arrow shaped cursor on the screen that moves when you move the mouse Programming Language A standardized communication technique for expressing instructions to a computer It is a set of syntax and semantic rules used to define computer programs A language enables a programmer to precisely specify what kinds of data a computer will act upon and precisely what actions to take under various circumstances RAM Random Access Memory the computer s electronic memory your work area Random Access The name given to the method of accessing the data in a file by using fixed length records that can be written to or read from in any order Reboot The computer term for restarting your computer Reserved Word A word which in some computer languages cannot be used as an identifier because it is already used for some grammatical purpose Resolution The number of pixels the monitor screen can use to display an image or dots your printer can print Restore Button The button in the middle of three buttons located at the right end of the titlebar on a maximized win
266. osS left yesOrNoS 1 if yesOrNoS y or yesOrNoS Y then continueA ifYesOrNo n or yesOrNo S N then end print Please answer Y or N goto askAgain continueA some more code here end more than one end statement is allowed EXP n Description This function returns e n with e being 2 7182818 Usage print exp 5 produces 148 41315 EVAL code Description Liberty BASIC now has two functions for evaluating BASIC code inside a running program The eval function evaluates the code and returns a numeric value and the eval function works the same way but returns a string value Both will execute the very same code but the string function converts the result to a string if it isn t already one and the numeric version of the function converts it to numeric values Evaluating to a string Here we show how to evaluate code to a string and what happens if you try to evaluate it to be a number Let s evaluate some code that produces a non numeric result a 0 zero a 1 one a 2 two code aS int str rnd 1 3 print We will evaluate the code codes resultS evalS code print results Now let s use the eval function which effectively does a val to the result of the calculation Converting a non numeric string to a numeric value results in zero result eval code print result Evaluating to a number Here s an example of the m
267. ose any open files or devices without posting a notice to that effect Usage open Graphic print gWin print gWin for graphics as gWin for index 1 to 100 print gWin print gWin next index input Press close gWin home down go index Hagen 63 Return Me LS open a graphics window center the pen put the pen down loop 100 times move the pen foreward turn 63 degrees this appears in main window close graphic window CLS Description This command clears the mainwin of text and sets the cursor back at the upper left hand corner It is useful for providing a visual break to separate different functional sections of a program Additionally since the main window doesn t actually discard past information on its own the CLS command can be used to reclaim memory from a program by forcing the main window to dump old text Usage print The total is grandTotal input Press Return to continue r cls print Enter Next Round of Figures COLORDIALOG Basic colors ml WI WEI DIF E LIE I Lal E E E E E EEE Eee Nnn EEE WI Custom colors ii i i i ip g BEE EEE g 5 Define Custom Colors gt gt Cancel COLORDIALOG color chosen Description This command displays the Windows Common Color Dialog to allow a user to select a color It returns the red green and blue components of the color chosen plus the Liberty BASIC name if it happens to co
268. ositive and and negative numbers and it is not limited to integer values For example for x 0 to 1 step 01 print The sine of x is sin x next x Optional variable with next Liberty BASIC 3 makes the use of a variable after next optional but if one is designated it must match the variable use with for Example Correct for x 0 to 1 step 01 print The sine of x is sin x next Incorrect for x 0 to 1 step 01 print The sine of x is sin x next y Exiting a loop prematurely GOSUB FUNCTION and SUB may be used within a FOR NEXT loop because they only temporarily redirect program flow or call on other parts of the program Program execution resumes within the FOR NEXT loop in these instances Program execution does not return to the FOR NEXT loop if GOTO is used within the loop GOTO should not be used to exit a FOR NEXTloop EXIT FOR will correctly exit the loop before it would have terminated normally for index 1 to 10 print Enter Customer index input customers if customer then quitEntry 1 don t cut out of a for next loop like this cust index customer next index quitEntry is not allowed Rather use while wend index 1 while customer lt gt and index lt 10 print Enter Customer index input customers cust index customerSe index index 1 wend EXIT FOR If it is necessary to exit a loop before the counter va
269. ost common type of code evaluation users will want to do Numeric computation Let s just make a short example that asks you to type an expression to evaluate ask for an expression input Type a numeric expression gt codeS answer eval code print answer EVAL code Description Liberty BASIC now has two functions for evaluating BASIC code inside a running program The eval function evaluates the code and returns a numeric value and the eval function works the same way but returns a string value Both will execute the very same code but the string function converts the result to a string if it isn t already one and the numeric version of the function converts it to numeric values Evaluating to a string Here we show how to evaluate code to a string and what happens if you try to evaluate it to be a number Let s evaluate some code that produces a non numeric result a 0 zero a 1 one a 2 two code aS int str rnd 1 3 print We will evaluate the code codes resultS evalS code print results Now let s use the eval function which effectively does a val to the result of the calculation Converting a non numeric string to a numeric value results in zero result eval code print result Evaluating to a number Here s an example of the most common type of code evaluation users will want to do Numeric computation Let s just make a short example that asks
270. ot be used to exit a WHILE WEND loop EXIT WHILE will correctly exit the loop before it would have terminated normally The following example is an example of a WHILE WEND loop exited improperly while count lt 10 input Enter a name or a blank line to quit n if n then exitLoop list count n count count 1 wend exitLoop Instead use the EXIT WHILE statement while count lt 10 input Enter a name or a blank line to quit n if n Dn then EXIT WHILI wend Gl exitLoop print Done WindowWidth Description The special variables WindowWidth and WindowHeight specify the width and height of the next window to be opened Ifthe program s code does not specify the values for these special variables their defaults will be 320 and 360 respectively After a resize event that is trapped by the resizehandler command these variables contain the width and height of the client area of the window the client area is the workspace of the window that is contained within the sizing frame border or titlebar See resize bas for an example of this usage Usage The following example will open a graphics window 250 pixels wide and 100 pixels high WindowWidth 250 WindowHeight 100 open test window for graphics as testHandle input r See also UpperLeftX UpperLeftY Resizehandler WORD s ni WORD stringExpression n string delimiter Description This function r
271. ould you like to repeat the last sequence gosub yesOrNo if answerS Y then repeat goto generateNew yesOrNo input answers answerS left answer 1 if answerS y then answerS y if answerS n then answer N if answerS Y or answer N then return print Please answer Y or N goto yesOrNo Using GOSUB yesOrNo in this case saves many lines of code in this example The subroutine yesOrNo could easily be used many other times in such a hypothetical program saving memory and reducing typing time and effort This reduces errors and increases productivity Note see also GOTO GLOBAL GLOBAL var1 var2 varN Description This statement specifies that the variables listed are global in scope They are visible inside functions and subroutines as well as in the main program code Global variables can be modified inside functions and subroutines as well so care must be taken not to alter them accidentally because this can easily cause errors in the program that are difficult to isolate Use global variables for things like values for true and false file paths user preferences etc See also Function Sub Usage global true false fonts true 1 false 0 font times new roman 10 Special Globals The special capitalized globals like WindowWidth DefaultDir the color setting variables etc that Liberty BASIC has supported since globals were first introduced in LB2 are no
272. ow from opening If NOMAINWIN is used when all other windows owned by that program are closed then the program terminates execution automatically It is often better to place a NOMAINWIN statement in a program after it is completed and debugged so that you can easily terminate an errant program just by closing its mainwin Usage NOMATINWIN Open Test for window as win wait NOTICE A Super Stats is Copyright 2001 Mathware NOTICE string expression Description This command pops up a dialog box which displays string expression and includes an OK button which the user presses after the message is read Pressing the ENTER key also closes the notice dialog box string expression Two forms are allowed If string expression has no carriage return character ASCII 13 then the title of the dialog box is Notice and string expression is the message displayed inside the dialog box If string expression does have a Chr 13 then the part of string expression before Chr 13 is used as the title for the dialog box and the part of string expression after Chr 13 is displayed as the message inside Further Chr 13 will force line breaks into the text contained in the message Usage notice Super Stats is Copyright 2001 Mathware notice Fatal Error chr 13 The entry buffer is full ON ERROR ON ERROR GOTO branchLabel Description Liberty BASIC 4 adds support for ON ERROR GOTO Sev
273. ow that shows how to build a rectangle structure often used in making Windows API calls See also Using types with STRUCT and CALLDLL Constants Liberty BASIC has a library of defined Windows constants _SW_HIDE being one This is equivalent to the definitions made in the windows h file that comes with most C compilers The way to inline a Windows constant is to take the name of the constant and place an underscore in front of it _SW_HIDE is the same as the Windows constant SW_HIDE If Liberty BASIC does not know the value of a Windows Constant it will generate an undefined constant message when compiling program In this case the numeric value of that constant must be determined from other sources SAMPLE PROGRAM Here is a short code sample but not a complete program using all of the above statements functions NOMAINWIN create the structure winRect struct winRect orgX as long orgY as long cornerX as long cornerY as long define sizes openingWidth 600 xpandedHeight 400 open USER32 DLL open user32 dl1 for dll as user button main showMore Hide Me hide UL 10 10 open An Example for window as main main trapclose quit get the window handle for main a standard Liberty BASIC window hMain hwnd main call the GetWindowRect API to load the window position size into winRect calldll user GetWindowRect hMain as long winRect as struct result as boolean ex
274. pad exe call132 5 bas code Gw NORMAL notice str code calldll kernel WinExec prognameS as struct code as long _ result as long print result close kernel input r Using hexadecimal values Liberty BASIC allows values to be expressed as hexadecimal numbers This is especially useful when calling API functions or using third party DLLs where the values specified in the documentation are in hexadecimal base 16 To convert a hexadecimal value use the HEXDEC function Here is an example print hexdec FF To convert a decimal value into a hexadecimal string use the DECHEXS function print dechex 255 Back to Making API and DLL Calls Using types with STRUCT and CALLDLL The STRUCT statement requires that each field be typed to specify what type of data it will contain The CALLDLL statement also requires that each parameter passed be typed The types are common to both STRUCT and CALLDLL Simple data TYPES in Windows programming are often renamed versions of the types below A program should specify the TYPE according to the chart below TYPES double a double floating point ulong 4 bytes unsigned long integer long 4 bytes signed long integer short 2 bytes signed short integer ushort word 2 bytes unsigned short integer ptr 4 bytes long pointer for passing strings struct 4 bytes long pointer for passing structs void none a return type only used when a functio
275. ple of a program which resizes several controls in a window depending on how the user changes the size of the window nomainwin WindowWidth 550 WindowHeight 410 listbox resizer lboxl array lbox1lDClick 1 0 256 186 listbox resizer lbox2 array lbox2DClick 257 0 284 164 combobox resizer cbox3 arrayS cbox3DoubleClick 257 164 283 150 texteditor resizer tedit4 1 186 540 195 open Resizing example for window as resizer print resizer trapclose quit loop print resizer resizehandler resized input r goto loop resized new sizes for width and height are now contained in the variables WindowWidth and WindowHeight wWid WindowWidth wHig WindowHeight upperVert int 256 550 wWid upper middle vertical edge midHoriz int 186 410 wHig middle horizontal edge urWid upperVert wWid print resizer lboxl locate 0 0 upperVert int 186 410 wHig print resizer lbox2 locate upperVert 0 wWid upperVert int 186 410 wHig 23 print resizer cbox3 locate upperVert midHoriz 23 wWid upperVert 100 print resizer tedit4 locate 0 midHoriz wWid wHig midHoriz print resizer refresh goto loop quit quit the program close resizer end WindowHeight Description The special variables WindowWidth and WindowHeight specify the width and height of the next window to be opened If the program s
276. port ATZ resets modems that understand the Hayes command set print commHandle ATZ To read from the port you should first check to see if there is anything to read This is accomplished in this fashion numBytes lof commHandle Then read the data using the input function dataRead S input commHandle numBytes Putting the oft and input functions together on one line it looks like this dataRead input commHandle lof commHand1le When you re all done close the port close commHandle Liberty BASIC 3 has added the ability to disable DSR checking by specifying a zero or non value using the DS switch open com1 9600 n 8 1 ds0 for random as com or open coml 9600 n 8 1 ds for random as com Liberty BASIC 3 02 has also added the txcount handle function to get a count of bytes in a serial communications transmit queue count txcount com See also ONCOMMERROR TXCOUNT handle OUT port byte OUT port byte Description This command sends a byte value to the specified machine I O port The use of this command inside Windows is considered to be only for those in the know Windows provides no method of ensuring that more than one application will not access any I O port at a time so use this command with care you know who you are If you will be distributing your application and it uses INP and or OUT to control hardware ports you will need to distribute and install certain fi
277. pression after it In the following example since value evaluates to the first CASE statement the printout says First case correct value 58 select case case value lt 10 or value gt 50 and value lt 60 print First case case value gt 100 and value lt 200 print Second case case value 300 or value 400 print Third case case else print Not evaluated end select If the expression value is placed after select case then none of the CASE statements is met so CASE ELSE is triggered which prints Not evaluated The expression must be omitted to evaluate multiple values ina SELECT CASE statement wrong select case value correct select case Nested statements Nested select case statements may be used Example select case atb case 4 5 select case c d case 100 do stuff end select do stuff case 6 7 do other stuff end select Bitwise Operations What are bitwise operations Bitwise operations modify the pattern of bits in an object Computers use binary numbers A binary number consists of one or more digits which represent two different states such as ayof An example of a binary number looks like this 10010 The first digit on the RIGHT side of the number is in the one s column The second digit from the right is in the two s column then comes the four s column the eight s column the sixteen s column and so on Each column contains a bit o
278. print handle ext setfocus This causes the radiobutton to receive the input focus This means that any keypresses will be directed to the radiobutton print handle ext locate x y width height This repositions the radiobutton in its window This is effective when the radiobutton is placed inside window of type window The button will not update its size and location until a REFRESH command is sent to the window See the included RESIZE BAS example program print handle ext font facename pointSize This sets the font to the specified face and point size If an exact match cannot be found then Liberty BASIC will try to find a close match with size taking precedence over face For more on specifying fonts read How to Specify Fonts Example print handle ext font times new roman 10 print handle ext enable This causes the control to be enabled print handle ext disable This causes the control to be inactive and grayed out print handle ext show This causes the control to be visible print handle ext hide This causes the control to be hidden or invisible Usage There are two demo programs below demonstrates radiobuttons with branch label event handlers nomainwin WindowWidth 520 WindowHeight 220 groupbox cfg Confirm File Operations 240 20 200 140 radiobutton cfg Aalways Always alwaysConfirm nil 260 45 130 20 radiobutton cfg AwhenReplacing When Replacing wh
279. r end if The dim info 10 10 statement is important because the files command in the function needs to have a double dimensioned array ready to accept its list of files and their information See FILES Path and Filename Complete Path and Filename References to a complete path and filename indicate that the drive letter and all folders and sub folders are included in the file specification A complete path and filename is returned by the FILEDIALOG An example of a complete path and filename is as follows C My Documents My Programs Games mygame bas Filename Alone References to a filename without path information indicate that the disk filename is used with no drive or folder information In Liberty BASIC use of a filename without path information assumes that the file exists on disk in the DefaultDir An example is as follows mygame bas Sub Folder A file that exists in a subfolder of the DefaultDir is written by first identifying the sub folder s each followed by a backslash then the filename like this images background bmp gamefiles images badguy bmp Relative Path Relative paths to files that exist in folders at the same level in the directory tree or in a higher level use the designation to indicate go up one level from the DefaultDir Filenames are usually designated by including a dot and a file extension that specifies the type of file Filenames ending in txt are text files for instance whi
280. r binary didt 16 8 4 2 1 This example binary number 10010 converted to a decimal number evaluates like this 16 8 4 2 1 0 0 1 1 16 1 16 8 0 0 4 0 0 2 1 2 1 0 0 total 18 in decimal numbers It is possible to operate on the bits using BOOLEAN operators AND The AND operator will set a bit only if both input bits are set Bitwise AND This operation sets a bit only if both inputs have the bit set print 7 and 11 yields 3 168421 i 00111 7 in binary 01011 11 in binary GER These are the place values where both numbers are 1 U U Hence 2 1 3 OR The OR operator will set a bit if either input bit is set Bitwise OR This operation sets a bit if either input has the bit set print 7 or 11 yields 15 168421 Bs cs ees EE A 7 in binary 01011 11 in binary values wher ither SE These are the plac number has a 1 t Hence 8 4 2 1 XOR 15 The Bitwise XOR operation sets a bit only if exactly one of the inputs has the bit set Bitwise XOR This operation sets a bit only if exactly one of the inputs has the bit set print 7 xor 11 yields 12 16 842 1 EE U 0 0 T I 7 in binary AE e e 00 gt a Sb 11 in binary 1 7 These are the plac of the values wher xactly one l numbers has a 1 Hence 8 4 12 See also BOOLEAN Boolean Evaluations What are booleans
281. r subroutine where execution begins when the user selects an item from the listbox by double clicking Selection by only single clicking does not cause branching to occur unless a singleclickselect command is issued to the listbox See also Controls and Events X y This is the distance in x and y in pixels of the listbox from the upper left corner of the window wide high This specifies the width and height in pixels of the listbox Here are the commands for listbox print handle ext select string This selects the item the same as string and updates the display If a variable is to be used in this command it must be located outside the quotation marks with the blank space preserved print handle ext select string print handle ext selectindex i This selects the item at index position i and updates the display Note that i must be a valid index number for the listbox array If a variable is to be used in this command it must be located outside the quotation marks with the blank space preserved print handle ext selectindex i print handle ext selection selected This will place the string of the item currently selected into selected If there is no selected item then selected will be a string of zero length a null string print handle ext selectionindex index This will place the index of the currently selected string into index If there is no selected item then index will be set to 0
282. rRed amp Yellow colorYell e Thickness lineThickness cttn bap colorRed UL 5 S bmpbutton 1 bmp yllwbttn bmp colorYellow UL 4 bmpbutton 1 bmp grnbttn bmp colorGreen UL 75 1 hmnihlueht t n hmn CenlarRluel IT hrmhurt t nn Now Liberty BASIC will take a few seconds to compile and run the drawing program some computers will take longer than others When it is finished compiling a window belonging to the drawing program will appear Liberty Draw ell sl Object Color Drawing Use Salo Let s try drawing a little something with Liberty Draw Liberty Draw Bisi x Object Color Drawing we Sao ep mmm n Wm Feel free to play with Liberty Draw and when you re done close its window Customizing the Liberty BASIC Editor Make the Liberty BASIC editor work the way you want it to work Select the Set Up menu to configure Liberty BASIC to your preferences The Preferences Dialog The Preferences Dialog is described in detail in the section on Editor Preferences From the Set Up menu you can also set the font face and size that will appear in the editor set the printer font face and size that will be used to print code from the editor and also for Iprint commands set up external programs to run from the Run menu These can be executables or Liberty BASIC TKNs run the Icon Editor Editor Preferences Liberty BASIC Preferences See
283. rams named CALL32 BAS that are included with Liberty BASIC CALL32 4 BAS Make some API calls to play wave files and dynamically resize a window open kernel32 for dll as kernel open user32 for dll as user open winmm for dll as mm open Me for window as aWindow print strS playMode wavefileS chimes wav playMode 4 calldll mm sndPlaySoundA wavefileS as ptr playMode as long result as long hndl hwnd aWindow for x 50 to 350 step 5 calldll user MoveWindow hndl as ulong 50 as long 50 as long x as long x as long I as long _ result as boolean next x input r prognameS notepad exe code _SW_SHOWNA notice str code calldll kernel WinExec prognameS as struct code as ushort _ result as ushort print result close kernel input r KKKKKKKKKKKKKKKKKKK KKK KKK KKK KKK KKK kk kk kk kk kk CALL32 5 BAS make various API calls to play wave files track the mouse position and move a window around struct point x as long y as long open kernel32 for dll as kernel open user32 for dll as user open Me for window as aWindow hndl hwnd aWindow for i 1 to 500 calldll user GetCursorPos point as struct result as void x point x struct y point y struct calldll user MoveWindow hndl as ulong x as long y as long _ 100 as long 100 as long 1 as long _ result as boolean next x prognameS note
284. ranch Labels Branch labels are locally scoped Code inside a function cannot see branch labels outside the subroutine and code outside a function cannot see branch labels inside any subroutine End Function The function definition must end with the expression end function Executing Functions Be sure that a program doesn t accidentally flow into a function A function should only execute when it is called by command in the program wrong for i 1 to 10 do some stuff next i Function MyFunction paraml param2 do some stuff MyFunction value End Function correct for i 1 to 10 do some stuff next i WAIT Function MyFunction paraml param2 do some stuff MyFunction value End Function Example Usage count the words input Type a sentence gt sentences print There are wordCount sentence end function wordCount aString index 1 while wordS aString index lt gt index index 1 wend wordCount index 1 end function See also SUB Recursion Functions and subroutines words in the sentence GET h n GET handle recordNumber Description GET is used after a random access file is opened to get a record of information see FIELD from a specified position Usage open custdata 001 for random as cust len 70 open random access file field cust 20 as nameS 20 as streetS 15 as city S 2 as stateS 10 as zipS 3 as age get the data fro
285. rcle r This command draws a circle with radius r at the current pen position print handle circlefilled r This command draws a circle with radius r and filled with the color specified using the BACKCOLOR command print handle cls This command clears the graphics window erasing all drawn elements and flushed segments and releasing all the memory they used print handle color COLOR This command sets the pen s color to be COLOR Here is a list of valid colors in alphabetical order black blue brown buttonface cyan darkblue darkcyan darkgray darkgreen darkpink darkred green lightgray palegray pink red white yellow Palegray and Lightgray are different names for the same color Buttonface is the default background color currently set on a user s system so it will vary according to the desktop color scheme Here is a graphical representation of the named colors yellow brown red darkred pink darkpink blue darkblue green darkgreen cyan darkcyan white WW Ga lightgray DO darkgray print handle color red 0 255 green 0 255 blue 0 255 The second form of color specifies a pure RGB color This only works with display modes greater than 256 colors To create a violet color for example mix red and blue print handle color 127 0 127 print handle delsegment n This causes the drawn segment with segment ID number n to be removed from the window s list of drawn items The memory th
286. re is a background image Bitmaps are rectangular images like the one above A program might need to put a picture of a hopping frog onto this background Here is the picture of a frog The frog is a bitmap also and bitmaps are rectangular Here is the bitmap of the frog drawn onto the background That doesn t look very convincing It is possible to make it look like the frog is part of the picture by using sprites When done with sprites the picture looks like this How Do Sprites Work As was explained in the previous section bitmaps are rectangular Realistic graphics require a way to place the image from a bitmap onto a background without including the image s own background If this were to be done with an actual picture on a piece of paper desired parts of the image could be cut out and the remaining parts of the picture could be discarded This cutout could then be pasted onto the background This can be done with bitmaps MASKS Images are added to a background in layers There are two versions of the image which are called a mask and a sprite The mask is put on first A mask has a white background The shape of the image is the actual mask and it is all black A mask is a black and white image Here is a mask for the frog image gt SPRITES The sprite is the image as it will appear with a completely black background SPRITES WITH MASKS Here is the bitmap for the frog sprite The mask is directly
287. reports that smiley collided with smiler and smiles during that frame of animation The third line reports that smiley collided only with the sprite named smiler during that frame of animation The fourth line reports that smiley did not collide with any other sprites during that frame of animation list smiler smiled smiles list smiler smiles list smiler lists nn Here is a picture of a sprite collision The frog sprite has touched one of the bug sprites Knowing this the program would probably change the bug sprite s visibility property to OFF and move it away from the active playing field or simply reset the location of the bug so that it appeared to be a new bug If this were a game a point would probably be added to the score here also Collision detection provided by Liberty BASIC uses the entire sprite image all the way to the corners to determine collisions unless a SPRITEROUND command is issued ROUNDED SPRITES AND COLLISIONS Sprite collisions are triggered when two sprites touch one another If a sprite image fills the rectangle that contains it the collision is triggered properly Many sprite images do not fill the corners of the rectangles containing them but are actually more rounded shapes If a SPRITEROUND command is issued to a sprite and it collides with another sprite that has received the SPRITEROUND command collisions are detected in an area that rounds off the corners assuming that
288. riable has reached its final value use the EXIT FOR statement This allows the program to exit the loop properly and to preserve the current value of the counter variable Use it like this for x 1 to 20 y x 3 if y gt 40 then EXIT FOR next x print Final x value x print Final y value y Output Final x value 14 Final y value 42 FUNCTION See also Functions and Subroutines BYREF function functionName zero or more parameter variable names code for the function goes in here functionName returnValueExpression end function Description This statement defines a function The function can return a string value or a numeric value A function that returns a string value must have a name that ends with the character A function that returns a numeric value must not include a in its name Zero or more parameters may be passed into the function A function cannot contain another function definition nor a subroutine definition Note that the opening parenthesis is actually part of the function name Do not include a space between the name and the opening parenthesis or the code generates an error Right function functionName varl var2 Wrong function functionName varl var2 Returning a Value To return a value from the function assign the value to be returned to a variable of the same name as the function If no return value is specified then numeric and string functions will return 0 an
289. right button has been double clicked mouseMove the mouse moved when no button was down characterlnput a key was pressed while the graphics window has input focus see the setfocus command above WARNING using graphicboxes in dialog type windows is fine but they do not properly accept the input focus for keyboard input If a program needs graphicboxes that trap keyboard events then a window of type window must be used See also Graphics Inkey Using Virtual Key Contants wiht Inkey Using Inkey Reading Mouse Events and Keystrokes Sprite Table of Contents Only one graphicbox or graphics window in a program may use sprites Sprite Commands What is a Sprite How Do Sprites Work Start with the Background Designate Sprites Sprite Properties Drawing and Collision Detection Flushing Sprite Graphics Pauses and Timing Add a Mask Step by Step Simple Demo Program Lander bas Sprite images used in some demos are by Ari Feldman User License 209 83 123 9 971442511 http www arifeldman com Sprite Commands Only one graphicbox or graphics window in a program may use sprites ADDSPRITE print w g addsprite SpriteName BmpName This adds a sprite with name SpriteName from loaded bitmap called BmpName print w g addsprite SpriteName bmpl bmp2 bmp3 bmpLast This adds a sprite with name SpriteName from loaded bitmaps may include any number of bitmaps BACKGROUND print w g background BmpName This se
290. rive A B or C PROMPT string expression responseVar Description The PROMPT statement opens a dialog box displays the message contained in string expression and waits for the user to type a response in the textbox and press the ENTER key or press the OK or Cancel button on the dialog The entered information is placed in responseVar If Cancel is pressed then a string of zero length is returned If responseVar is set to some string value before PROMPT is executed then that value will become the default or suggested response that is displayed in the textbox contained in the PROMPT dialog This means that when the dialog is opened the contents of responseVar will already be entered as a response for the user who then has the option to either type over that default response or to press Return and accept it Caption for the Prompt Window string expression Two forms are allowed If string expression has no carriage return character ASCII 13 then the caption or title on the dialog box is blank and string expression is the message displayed inside the dialog box If string expression does have a Chr 13 then the part of string expression before Chr 13 is used as the title for the dialog box and the part of string expression after Chr 13 is displayed as the message inside Usage response C prompt Search on which Drive A B or C responses testResponse if response then
291. roducing formatted output to a file or printer Usage for x 1 to 10 print space x next x Wy Produces Text mode display TEXT DISPLAY IN THE MAINWIN Liberty BASIC is designed for building Windows programs It is also possible to write rudimentary text mode programs By default each Liberty BASIC program has a main window called the mainwin This is a simple text display with scrollbars Displaying Text The standard PRINT command causes text to be displayed in the mainwin print Hello World produces Hello World After the expressions are displayed the cursor that blinking vertical bar will move down to the next line and the next time information is sent to the window it will be placed on the next line down To prevent the cursor from moving immediately to the next line add an additional semicolon to the end of the list of expressions This prevents the cursor from being moved down a line when the expressions are displayed The next time data is displayed it will be added onto the end of the line of data displayed previously Usage Produces print hello world hello world print hello hello world print world age 23 print Ed is age years old Ed is 23 years old Getting User Input User input is obtained by use of the INPUT command in the mainwin Here is a simple example Ask the user a question input Hi What s your name yourNameS print Nice to meet you yourName
292. rogram above draws a sine wave discarding drawn graphics If the graphics window is maximized after the drawing is complete it is possible to see that the graphics are not redrawn This is similar to the effect achieved when FLUSH is not used but in fact it throws away the graphics instructions so memory does not get filled up When a window is closed all graphics drawing operations are deleted from memory See also graphics commands Reading Mouse Events and Keystrokes A graphics window or graphicbox is able to read mouse and keyboard input Here is the world s smallest painting program open Paint something for graphics as w print w when leftButtonMove paint print w when characterInput letter print w down size 3 wait paint print w set MouseX MouseY wait letter print w Inkey wait The mouse location within the graphics area can be retrieved from the MouseX and MouseY variables The Inkey variable holds the character of the key pressed In order to capture keyboard input the graphics device must have focus Sometimes it is necessary to force the input focus using the setfocus command print w g setfocus Mouse actions example with subroutine event handler Here s a really simple illustrative example of a paint program When the leftButtonDown event happens the draw subroutine gets called and the graphicbox handle and mouse x and y values get passed in a simpl
293. rrelate to one of the 16 named LB colors Usage color This is a string containing the starting color for the dialog It can be an empty string but it must be included It may be in one of two forms It can be a named Liberty BASIC color or a string containing the red green blue values of the desired color with which to seed the colordialog chosen When the dialog is closed this variable contains the color chosen by the user Examples colordialog red chosen print Color chosen is chosen or colordialog 255 0 0 chosen print Color chosen is chosen Red green and blue values must each be in the range of 0 to 255 0 is the absence of a color and 255 is total saturation After the dialog closes the receiver variable contains the red green blue values for the color chosen by the user If these values correlate to a named Liberty BASIC color that color name will be appended to the returned string Returned string RGB and name for a named color 255 255 0 yellow Returned string RGB only for a non named color 250 230 190 Full Opening of Dialog The colordialog opens a small dialog with a grid of typical colors displayed The user can choose to click the Define Custom Colors button to open a full RGB color spectrum from which to choose The full dialog looks like this Color Basic colors Custom colors RSR Hue Red 8 Sat 1 coal Defne Custom ealas gt gt ColorlS olid Lum d 20 OK
294. s print whoops print Error divideBy resume sub causeWhoops 2 Wwe DH Errs print 10 divideBy end sub Ww Wwe DH Ww code Wwe DH ONCOMERROR ONCOMERROR branchLabell Description This sets or clears a branch label for handling errors when doing serial communications to set a branch label for error handling oncomerror myComErrorHandler to disable com error handling oncomerror When an error does occur three special variables will be set ComError This holds a description of the error ComPortNumber This holds the port number of the error ComErrorNumber In the case of Win 95 98 ME this var is set to one of the Win16 com error codes and in the case of Win NT 2K XP OS error codes Usage open com2 open COM2 9600 n 8 1 for random as 1 enable the com error handler oncomerror handleIt try to open com2 again triggering handler open COM2 9600 n 8 1 for random as 2 we never get this far because of the error print we never get this far because of the error input r handleIt disable the com error handler oncomerror print out the error and port print Error ComError s print Port number ComPortNumber print Error code ComErrorNumber close com2 close 1 end See also OPEN COMn OPEN OPEN device FOR purpose AS handle LEN n Description The OPEN command opens communication with a device
295. s set wait sub doRadio handle notice You selected handles if handleS win yes then status yes if handleS win no then status no end sub sub Quit handles close handle end end sub Note see also CHECKBOX For information on creating controls with different background colors see Colors and the Graphical User Interface RANDOMIZE RANDOMIZE n Description This function seeds the random number generator in a predictable way The seed numbers must be greater than 0 and less than 1 Numbers such as 0 01 and 0 95 are used with RANDOMIZE Usage this will always produce the same 10 numbers randomize 0 5 for x 1 to 10 print int rnd 1 100 next x READ Description This fetches the next strings and or numeric values from DATA statements in a program The READ statement will fetch enough items to fill the variable names the programmer specifies The values fetched will be converted to fit the variables listed string or numeric Example read the numbers and their descriptions while desch lt gt end read desc value print desc is the name for value wend here is our data data one hundred 100 two 2 three 3 end O0 end You can also read numeric items read the numbers and their descriptions while desch lt gt end read desch value print desc is the name for valueS length len value wend here is our data data one hundred 100 t
296. s an excellent way to prevent errors from occuring If an end tag or flag of some sort is not used be sure that other checks are in place to prevent the READ statement from trying to access more DATA items than are contained in the DATA statements See also READ RESTORE READ and DATA DATES Description Instead of adopting the date variable from QBasic Liberty BASIC uses a function instead This approach gives some additional flexibility Unless otherwise indicated the function returns today s date in the format specified See also TIMES Date and Time Functions Usage This form dateS produces this format print dates Nov 30 1999 print as a en 11 30 1999 print date mm dd yy 11 30 99 print dateS yyyy mm dd 1999 11 30 for sorting print dateS days IT 36127 days since Jan 1 1901 print date 4 1 2002 36980 days since Jan 1 1901 for given date print dates 36980 04 01 2002 mm dd yyyy string returned when given days since Jan 1 1901 You can assign a variable to the result d date NOTE All the above forms return a string except for date days and date 4 1 02 Using the date 4 1 02 function This function returns the number of days since Jan 1 1901 for the given date Any of the following formats are acceptable Please notice that if the first two digits of the year are omitted 20xx is assumed some examples print date 4 1 02 this assumes
297. s ina window to courier new 8pt italic print handle font courier new 8 italic When using a text window precede the command with a character open Font Test for text as handle print handle font courier new 8 italic wait For more on specifying fonts read How to Specify Fonts To override this general font command font commands may be sent to individual controls after this command is issued See the command listss for individual controls for control specific documentation If a control can accept a new text string such as a caption the font command must be preceded by a character Examples some controls require font print h button font courier new 8 italic print h textbox font courier new 8 italic some controls do not require a character print h graphicbox font courier new 8 italic print h radiobutton font courier new 8 italic RESIZEHANDLER This command sets up an event handler that is activated when the user resizes a window of type window This command is not useful for dialog windows or for windows without a sizing frame See also the REFRESH and LOCATE commands below set up a handler for when the user resizes a window print handle resizehandler branch OF 5 23 clear the resizing handler print handle resizehandler See the example program RESIZE BAS LOCATE This command is useful when the RESIZEHANDLER command is used see above After a user resizes a w
298. s must be preceded by the character If not they will simply be displayed in the textbox texteditor or text window as text In the example above column and row are standing in for hard coded values As it might appear in a program print win select 3 4 OR RK 3 b 4 print win select a b See also Text Commands Control Commands BUTTON handle ext label clickHandler corner x y In the above BUTTON command handle stands in for the window handle as it appears in your program The ext stands in for the extension given to the control when it was created label stands in for the label desired on this button clickHandler stands in for the desired branch label for the event handler for this button corner stands in for the desired anchor corner and x y stand in for the actual locations These can be hard coded or they can be variables Here are some possible BUTTON commands as they appear in a program BUTTON main okay Okay doOkay UL 10 20 BUTTON win 1 Cancel quitMe UL 43 112 x 112 y 34 BUTTON 1 2 Print printClick UL x y Here is another example that shows the syntax for CHECKBOX CHECKBOX handle ext label set reset x y wide high As it appears in a program CHECKBOX win checkl Make Backup setBackup resetBackup 300 22 100 24 See also Controls Size and Placement of Windows NOTE Beginning with Liberty B
299. s print var 2 then a list of squares for var will be displayed upon execution The specified range could just as easily be 2 TO 20 instead of 1 TO 10 but since the loop always counts 1 at a time the first number must be less than the second The way around this limitation is to place STEP n at the end of for FOR statement for index 20 to 2 step 1 BASIC code next index This loops 19 times returning values for index that start with 20 and end with 2 STEP can be used with both positive and and negative numbers and it is not limited to integer values For example for x 0 to 1 step 01 print The sine of x is sin x next x For more on For Next loops click here WHILE WEND As shown above Liberty BASIC includes a for next looping construct It also has a while wend looping construct Here is the above program rewritten using while wend count to ten x 0 while x lt 10 X x til1 print x wend end One useful thing that can be done with while wend is to wrap the boolean expression in a NOT function which effectively turns while wend into a while condition is false do construct count to ten while not x 10 XxX X 1 print x wend end For more on While Wend loops click here DO LOOP Liberty BASIC also provides a DO LOOP structure for cases when you want a loop that always executes once and then only loops back as long as a condition is met It will continue looping back and exe
300. s usefulness Consider retry input Please choose mode N ovice or e X pert modes if len mode 0 then print Invalid entry Retry goto retry modes left mode 1 if instr NnXx mode 0 then print Invalid entry Retry goto retry if instr Nn modeS gt 0 then print Novice mode goto main print eXpert mode main print Main Selection Menu The conditional lines can be shortened to one line as follows if instr Nn mode gt 0 then print Novice mode else print eXpert mode Some permitted forms are as follows if a lt b then statement else statement if a lt b then label else statement if a lt b then statement else label ifa lt b then statement statement else statement ifa lt b then statement else statement statement if a lt b then statement goto label else statement if a lt b then gosub label1 else gosub label2 Any number of variations on these formats are permissible The a lt b BOOLEAN expression is of course only a simple example chosen for convenience It must be replaced with the correct expression to suit the problem IEF THEN END IF is another form using what are called conditional blocks This allows great control over the flow of program decision making Here is an example of code using blocks if qtySubdirs 0 then print None goto noSubs end if A block is merely one or more lines of code that are executed as a result of a conditio
301. se while string lt gt end read strings print lowerS string wend data The Quick Brown Fox Jumped data Over The Lazy Dog and end Optionally you can choose to include a branch label show me my data in all uppercase while string lt gt end read strings print upperS string wend stringS clear this for next while wend loop now reset the data reading to the second part restore partTwo show me my data in all lowercase while string lt gt end read strings print lowerS string wend data Sally Sells Sea Shells By The Sea Shore partTwo data Vhet hs Do Only THIS A Second Time end end See also DATA READ READ and DATA RESUME RESUME Description The RESUME command can be used to attempt a retry when an error is handled using the ON ERROR GOTO statement There is no way to specify an alternative If the error is handled in a sub or function RESUME must be attempted before the sub or function ends or else you will get an error when attempting to RESUME Usage demonstrate the use of RESUME on error goto whoops global divideBy call causeWhoops end whoops print whoops print Error p Erro T code Y Err divideBy 2 resume sub causeWhoops print 10 divideBy end sub RETURN RETURN Description This statement causes program execution to continue at the ne
302. ses the control to be visible print handle ext hide This causes the control to be hidden or invisible BYREF Function functionName byref var byref var2 Description Variables passed as arguments into functions and subs are passed by value by default which means that a copy of the variable is passed into the function or sub The value of the variable is not changed in the main program if it is changed in the function A variable may instead by passed byref which means that a reference to the actual variable is passed and a change in the value of this variable in the function or sub changes the value of the variable in the main program See also Function Sub Functions and Subroutines Usage Each of the parameters in the function and sub in this example use the byref specifier This means that when the value of a and b are changed in the function that the variables used to make the call x and y will also be changed to reflect a and b when the function returns Try stepping through this example in the debugger now you can pass by reference KS 5 3 y 7 2 result formatAndTruncateXandY x y print x x print y y print result and it works with subroutines too wizard gandalf call capitalize wizard print wizards end function formatAndTruncateXandY byref a byref b a int a b int b formatA AndTruncateXandY str a str b end function sub capitali
303. sition 304 15 yPosition 1 30 15 print makeSprites north up turn angle print makeSprites go 4 turn 235 go 8 down turn 45 EM end sub sub setBackground loadbmp stars bmp stars bmp print lander fill black call drawTerrain print lander getbmp stars 0 0 488 310 print lander background stars end sub sub getSprite spritNum spriteX spritNum 30 print makeSprites getbmp lem spritNum spriteX 60 end sub sub setHorizSpeed xSpeed vars 0 xSpeed end sub sub setVertSpeed ySpeed vars 1 ySpeed end sub function getHorizSpeed end getHorizSpeed function vars 0 function getVertSpeed getVertSpeed vars 1 end sub end sub end sub function setAttitude deg print lander sub rees spriteimage 1l m l We m gravityAccelerate call setVertSpeed getVertSpeed 4 sub applyThrust qtyFuel angle 180 3 141592 call setHorizSpeed getHorizSpeed angleXform angle 0 6 6 18 int degrees 22 5 qtyFuel cos angleXform 1 30 go go call setVertSpeed getVertSpeed qtyFuel sin angleXform end sub sub drawTerrain ratel rnd l rnd 1 17 10 rate2 rnd l rnd 1 10 10 print lander down size 1 color white for x 0 to 499 step 1 if rnd 1 lt 0 015 then gosub makeLandingZone holderl holderltratel holder2 holder2t rate2 hol
304. sk the previous contents will be overwritten and therefore lost Care should be taken when opening files for OUTPUT so that critical data is not accidentally erased See Testing For File Existence Data is written to a file opened for OUTPUT with a PRINT statement A line delimiter or carriage return is written to the file with each PRINT statement The carriage return may be suppressed by ending the line of code with a semi colon Example Program create a sample file open test txt for output as 1 write some data with line delimiters print 1 line one print 1 line two write some data without line delimiters rint 1 item three D rint 1 item four D more print print close data with line delimiters added 1 item five 1 done 1 INPUT to see what we wrote open test txt for input as 1 txt print print print close input 1 lof 1 Contents of file txts 1 Contents of file line one line two item three item four item five done APPEND Files opened for APPEND can be written to sequentially If a file opened for APPEND does not exist it will be created Ifthe file does exist on disk any data written to the file with a PRINT statement will be added to the end Writing data to the file works in the same way when a file is opened for APPEND as when it is opened for OUTPUT but rather than overwriting data contained in the file the new dat
305. smiley 20 50 Z ORDER Z order means the order in which the sprites are drawn A sprite on the bottom of the z order is drawn first so sprites drawn after it will appear to be on top of it A sprite at the top of the z order is drawn last so other sprites appear underneath it To bring a sprite to the top of the z order print w g spritetofront smiley To send a sprite to the bottom of the z order print w g spritetoback smiley IMPORTANT To avoid flickering sprite animation is done invisibly in memory A frame of animation is built entirely off screen A frame of animation is displayed on the screen only when the command DRAWSPRITES is called For each frame of animation perform all functions to set the background image and to set or change a sprite s properties then call the DRAWSPRITES command Now we re ready to start drawing the animated sprites See the section on Drawing and Collision Detection Drawing and Collision Detection UPDATING THE DISPLAY The DRAWSPRITES command updates the display causing all VISIBLE sprites to be drawn at their current LOCATIONS moving them if the SPRITEMOVEXY command has been issued They will display in their current SCALE and ORIENTATION This command must be given each time it is necessary to draw another frame of animation Sprite attributes may be changed in between the DRAWSPRITES commands including their location orientation and scale Ifthe background image is to be moved th
306. sort array 50 1 SPACE n Description This function will a return a string of n space characters or ASCII 32 It is useful when producing formatted output to a file or printer Usage for x 1 to 10 print spaceS x next x SQR n SQR n Description This function returns the square root of the number or numeric expressioin n Usage print The square root of 2 is print SOQR 2 Statictext Static T ext The syntax of this command is STATICTEXT handle string xpos ypos wide high or STATICTEXT handle ext string xpos ypos wide high Description Statictext lets you place instructions or labels into your windows This is most often used with a textbox to describe what to type into it The text contained in a statictext control is alligned to the left If the text is too long to fit the width of the control it will automatically wrap lines to fit handle This must be the same as the handle of the window that contains the statictext control If handle ext is used the program can PRINT commands to the statictext control If the control has no extension then it cannot receive commands to change the text label font or location string This is the text displayed on the statictext xpos amp ypos This is the distance of the statictext in x and y in pixels from the upper left corner of the screen wide amp high This is the width and height of the statictext Be sure to spe
307. t print handle ext locate x y width height This respositions the combobox in its window This is effective when the combobox is placed inside window of type window or dialog The combobox will not update its size and location until a REFRESH command is sent to the window See the RESIZE BAS example program print handle ext font facename pointSize This sets the control s font to the specified face and point size If an exact match cannot be found then Liberty BASIC will try to find a close match with size taking precedence over face For more on specifying fonts read How to Specify Fonts Example print handle ext font times new roman 10 print handle ext select string This selects the item the same as string and updates the display Note that string must be a valid item from the combobox array Ifa variable is to be used in this command it must be located outside the quotation marks with the blank space preserved print handle ext select string print handle ext selectindex i This selects the item at index position i and updates the display Note that i must be a valid index number for the combobox array Ifa variable is to be used in this command it must be located outside the quotation marks with the blank space preserved print handle ext selectindex i print handle ext selection selected This places the selected string into the variable selected If there is no selected item th
308. t locate x y width height This repositions the control in its window This is effective when the control is placed inside window of type window The control will not update its size and location until a REFRESH command is sent to the window See the RESIZE BAS example program print handle ext setfocus This causes the textbox to receive the input focus This means that any keypresses will be directed to the textbox print handle ext enable This causes the control to be enabled print handle ext disable This causes the control to be inactive and grayed out print handle ext show This causes the control to be visible print handle ext hide This causes the control to be hidden or invisible Dead Textbox Problem If it appears that no text can be typed into a textbox it may be that the textbox is not high enough to display the current font Try making the textbox higher or giving it a font command for a smaller font Textboxes can also appear to be dead if too many controls are placed on a window Sample Program sample program textbox name txt 20 10 260 25 button name OK titleGraph LR 5 0 WindowWidth 350 WindowHeight 90 open What do you want to name this graph for window nf as name print name txt untitled mainLoop wait titleGraph print name txt contents input name txt graphTitles notice The title for your graph is graphTitle close name
309. t a and b when the function returns Try stepping through this example in the debugger now you can pass by reference KEE y 7 2 result formatAndTruncateXandY x y print x x print y y print results and it works with subroutines too wizards gandalf call capitalize wizards print wizards end function formatAndTruncateXandY byref a byref b a int a b int b formatAndTruncateXandy str a str b end function sub capitalize byref words wordS upperS left wordsS 1 mid word 2 end sub More about pass by reference Passing by reference is only supported using string and numeric variables as parameters You can pass a numeric or string literal or a computed number or string or even a value from an array but the values will not come back from the call in any of these cases Step through the example in the debugger to see how it works you can also call without variables but the changes don t come back resultS formatAndTruncateXandY 7 2 5 3 print results and it works with subroutines too call capitalize gandalf a 0 snoopy call capitalize a 0 end function formatAndTruncateXandY byref a byref b a int a b int b formatAndTruncateXandy str a str b end function sub capitalize byref words wordS upperS left word 1 mid word 2 end sub Branch Labels GOTO and GOSUB See also GOSUB RETURN GOTO Functions
310. t ten numbers between one and ten for a 1 to 10 print int rnd 1 10 1 next a RUN s mode RUN StringExpr1 mode Description This command runs external programs StringExpri should represent the full path and filename of a Windows or DOS executable program a Liberty BASIC TKN file or a BAT file This is not a SHELL command so you must provide the name of a program or batch file not a DOS command like DIR for example Execution of an external program does not cause the calling Liberty BASIC program to cease executing Here are two examples RUN QBASIC EXE run Microsoft s QBASIC RUN WINFILE EXE SHOWMAXIMIZED run the File Manager maximized RUN WINHLP32 LIBERTY3 HLP run winhlp32 with the Liberty BASIC helpfile loaded RUN NOTEPAD NEWFOR302 TXT MINIMIZE run notepad minimized with a textfile loaded Notice in the second example you can include an additional parameter This is because it runs a Windows program Here is a list of the valid parameters we can include when running Windows programs HIDE SHOWNORMAL this is the default SHOWMINIMIZED SHOWMAXIMIZED SHOWNOACTIVE SHOW MINIMIZE SHOWMINNOACTIVE SHOWNA RESTORE SCAN Description The SCAN statement causes Liberty BASIC to stop what it is doing for a moment and process Windows keyboard and mouse messages This is useful for any kind of routine that ne
311. tY ABS n Description This function returns n the absolute value of n n can be a number or any numeric expression Usage print abs 5 produces 5 print abs 6 13 produces 7 print abs 2 4 produces 6 print abs 3 produces 3 print abs 3 2 produces 1 5 print abs 5 75 produces 5 75 ACS n Description This function returns the arc cosine of the number or numeric expression n The return value is expressed in radians Usage print The arc cosine of 0 2 is acs 0 2 Tip There are 2 pi radians in a full circle of 360 degrees A formula to convert degrees to radians is radians degrees divided by 57 29577951 Note See also COS ASC s Description This function returns the ASCII value of the first character of string s s can be a string variable or text enclosed in quotes Text and formatting characters have ASCII values from 0 to 255 See also CHR n Usage print asc A produces 65 let name Tim firstLetter asc name print firstLetter produces 84 print ase E produces 0 ASCII Chart of Printable Text Characters a MM Fe ge vo oO Jo D GA b i ON ID eis WM il Aw ss Ae D ss A de Meee oak EE ee oes e a ee ee ee es Ge a e e e rr vr vr vrwrvrwvrvrvrwvrvrwvrvrwvrvrvrwvrvrwvrvrvrvrwvr vr vrrvrwvrvrvrvrvrrvrvrwvrvrovrvrvrvrvrovrvrvrvr wy Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr C
312. taking precedence over face For more on specifying fonts read How to Specify Fonts Example print handle font Times New Roman 10 print handle getbmp bmpName x y width height This command will make a bitmap copied from the graphics window at x y and using width and height It resides in memory This bitmap can be drawn using the DRAWBMP command just as a bitmap loaded with LOADBMP It is also possible to get a Windows handle to this bitmap with the HBMP function print handle go D This causes the drawing pen tomove forward D distance fram the current positim moving inthe current directicn print handle goto X Y This command moves the pen to position X Y A line will be drawn if the pen is down print handle home This command centers the pen in the graphics window print handle horizscrollbar on off min max This command manages the horizontal scrollbar If the value is on the scrollbar is visible If the value is off the scrollbar is not displayed If the optional paramters for min and max are used they set the minimum scrollbar range and the maximum scrollbar range in pixels A large scrollbar range allows the graphics window to scroll a long distance while a short range allows it to scroll a short distance print handle line X1 Y1 X2 Y2 This command draws a line from point X1 Y1 to point X2 Y2 Ifthe pen is up then no line will be drawn but the pen will be positioned at X2 Y2 print
313. tation marks of the SPRITEXY command print w g spritexy smiley input w g X y OR print w g spritexy smiley x y IMPORTANT REMINDER To avoid flickering sprite animation is done invisibly in memory A frame of animation is built entirely off screen A frame of animation is displayed on the screen only when the command DRAWSPRITES is called For each frame of animation perform all functions to set the background image and to set or change a sprite s properties then call the DRAWSPRITES command Sprite graphics are temporary To learn about making sprite graphics remain in a graphicbox or graphics window even if the window is covered or minized read Flushing Sprite Graphics Flushing Sprite Graphics FLUSHING GRAPHICS In Liberty BASIC graphicboxes and graphics windows the drawings are lost if the window is covered by another window or if the window is minimized To make drawings stick use the FLUSH command The FLUSH command is used in conjunction with DELSEGMENT DISCARD REDRAW and CLS In the following example the graphicbox is filled with yellow The second line commands Liberty BASIC to remember this drawing operation and to repaint the graphicbox when needed so that it is always filled with yellow Without the FLUSH command the graphicbox reverts to its default color in any areas that were covered by another window and the entire graphicbox reverts to its default color when the window was minimized Th
314. ter this For example the factorial of 15 is 1307674368000 factorial input Compute factorial for n print factorial n end function factorial a factorial 1 if a gt 1 then factorial a factorial a 1 end function The Timer Statement Liberty BASIC includes a timer statement which uses the computer s hardware timer Most PCs have a timer with a resolution of approximately 56 milliseconds which ticks 18 times a second The timer allows the addition of a clock to a program or or it allows the program to wake up every few seconds to check for some condition or it can be used to control the rate of animation of a game There are other uses as well The TIMER command specifies how many milliseconds to wait between timer signals One second is 1000 milliseconds It also specifies a routine to serve as an event handler The timer may be turned off and then back on Here is a short example timer 3000 threeSeconds wait threeSeconds timer 0 confirm Three seconds have passed Do it again repeat if repeat then timer 3000 threeSeconds wait end if end See also TIMER Callbacks for API Functions Liberty BASIC 3 supports the use of a callback address that can be passed into an API function so that a function within a program can be called by an API function The syntax callback address functionNameProc type type return type For more see CALLBACK Variables See also Numeric Variables Stri
315. the collection Error Log Explained Sometimes the Liberty BASIC compiler finds a problem with your code and it will stop and give you an error message of some kind Usually this will appear on the status line at the bottom of the Liberty BASIC editor window At other times you may see a popup error notice when running a program that you ve written There are a variety of programmer errors which can give rise to such error messages For example perhaps a program tries to divide a number by zero which is mathematically impossible to do or maybe a program closes a file and then tries to close it again it isn t possible to close a file that isn t open These kinds of programmer bugs result in a popup error message However sometimes you will get a popup error notice that mentions the ERROR LOG file This means that you have stumbled across a nastier sort of bug in Liberty BASIC itself and Liberty BASIC has written something about that bug in the ERROR LOG file What should you do with the information in the ERROR LOG file Some people have contacted us more than a little confused after looking at the contents of the this file Don t worry This information is much more useful to us since it contains details about the internals of Liberty BASIC We have a pretty good idea what it means If you are so inclined you can send it to us and we ll take a look at it and try to help you with the bug and also use the information to fix bugs in new releas
316. the command to display the text When graphictext is designated by the use of the or character any semicolons that follow in the same line are considered to be part of the text string to display Important When drawing to a graphics window or graphic box the operations that are performed are stored in memory by Liberty BASIC so that lightning fast redraws can be performed This storage function uses memory If an application continually draws raphics the system will eventually run out of memory and even potentially crash the computer To prevent this the application should only store those drawing operations which are needed to display its current state The cls delsegment discard and flush commands help to manage graphics memory See also Graphics Liberty BASIC supports sprites in graphic windows and in graphicbox controls Only one graphicbox or graphics window in a program may use sprites To learn more about using sprites see Sprites Using variables in commands To use literal values place them inside the quotation marks print handle box 12 57 To use variables place them outside the quotation marks preserving spaces x 12 y 57 print handle box x y For more see Understanding Syntax GRAPHICBOX COMMANDS The following commands are sent to a graphicbox When a graphicbox is disabled it can no longer capture keyboard and mouse events print handle ext setfocus This causes the control to r
317. the command with the character for all windows and controls that can accept new text strings or the command will simply be displayed on the control See the topics for individual controls for control specific documentation texteditor print handle texteditor setfocus graphics window print graph setfocus button print handle button setfocus graphicbox print handle graphicbox setfocus ENABLE DISABLE These two commands cause a control to be enabled and active or disabled and inactive When a control is disabled it appears to be grayed out Begin the command with the character for all windows and controls that can accept new text strings or the command will simply be displayed on the control See the topics for individual controls for control specific documentation nomainwin button win bttn Hello hello UL 10 70 checkbox win cbox Goodbye quit quit 10 160 120 24 menu win amp Main amp Enable doEnable amp Disable doDisable E amp xit quit open Enable and Disable for window as win wait quit close win end doEnable win bttn Enable win cbox Enable wait doDisable win bttn Disable win cbox Disable wait hello wait SHOW HIDE These two commands cause a control to be visible or hidden Begin the command with the character for all windows and controls that can accept new text strings or the command w
318. the contents of the array REDIM students 30 Double dimensioned arrays must always be dimensioned with the DIM statement before use DIM scores 20 10 The equal sign is used to assign a value to an element in an array The element is referred to by its index number The index may be expressed as a literal number or as a numeric variable The element at index 2 in the following example is filled with John The element at index 7 is filled with the number 12 students 2 John ages 7 12 Arrays can be used in most places where a variable or literal value can be used To access the value of an element in an array the index for that element is placed inside the parentheses In this example the value at index 4 is retrieved from the array thisKid studentss 4 or print studentss 4 Using Arrays in Loops One of the great advantages of arrays is their ability to be accessed in loops as in the following example which prints the names of elements 1 30 that are contained in the array for i 1 to 30 print students i next Input to Arrays In earlier versions of Liberty BASIC it wasn t possible to input directly into arrays That limitation no longer exists in Liberty BASIC 3 It is now possible to use both Input and Line Input to read data from opened files directly into arrays now works open myfile dat for input as f input f itemArray 1 close f It is still necessary to READ dat
319. the size of a struct Usage prompt What is your name yourNameS print Your name is len yourName letters long struct person name as ptr age as long print len person struct LET var expression Description LET is an optional prefix for any BASIC assignment expression Most programmers leave the word out of their programs but some prefer to use it Usage Either is acceptable let nameS John or name John Another example let c sqr a 2 b 2 or c sqr a 2 b 2 LINE INPUT line input handle vars Description This gets the next data line from the open file or device using handle handle and assigns the data to var If no device or file exists that uses the handle named handle then it returns an error The line input statement reads from the file ignoring commas in the input stream and completing the data item only at the next carriage return or at the end of file This is useful for reading text with embedded commas Usage Display each line of a text file input Please type a filename gt filenames open filenameS for input as text loop if eof text lt gt 0 then quit line input text items print items goto loop quit close text print Done Arrays Line Input now allows input directly multiple variables and arrays filedialog Open txt fileS if fileS then end dim a 3000 open file for input as f while not eof line input f
320. the width in pixels of a string based on the current font of the graphicbox or graphic window open my stringwidth for graphics as g name Carl Gundel print 9 stringwidth nameS width print width print g font courier new 30 print 9 Sstringwidth nameS width print width close g end print handle text This command displays the specified text at the current pen position The text is located with its lower left corner at the pen position Each additional in the text will cause a carriage return and line feed For example print handle text1 text2 will cause text1 to be printed at the pen position and then text2 will be displayed directly under text1 also print handle text This command works like print handle text above but uses the character instead of the character which allows display of the character a print handle trapclose branchLabel This will tell Liberty BASIC to continue execution of the program at branchLabel if the user double clicks on the system menu box or pulls down the system menu and selects close this command does not work with graphicbox controls print handle turn A This command causes the drawing pen to turn from the current direction using angle A and adding it to the current direction A can be positive or negative print handle up This command lifts up the pen All GO or GOTO commands will now only move the pen to its new position
321. there again the breakpoint will disappear Add as many breakpoints as you like but keep in mind that adding a breakpoint to a blank line or a remark will not have any effect during debugging You can also right click on the breakpoint bar for a little popup menu When you launch the debugger it also has a breakpoint bar which will contain all the breakpoints you added in the editor You can add and remove breakpoints in the debugger Note Changes you make to the breakpoints in the debugger are not automatically made to the breakpoint bar in the editor Liberty BASIC v4 0 untitled bas oj EX File Edit Run Setup Help DSH e A ji pp Ze von OFF On for x 1 to 1000 print x N Toggle Breakpoint S Clear All b EE Breakpoint in the Debugger You can also click on a line of code in the debugging window to set the cursor right click to pop up a menu and then select Run to Cursor to make your program run at full speed until it reaches that line of code just as if you added a breakpoint to that line This method functions as a just once breakpoint Debugging Debugging a A H lineThickness oMousex oMouseY oMouseY House oMousex MousexX goto inputLoop trackLine int 1 tanlar white startX startyY lack print 1 place startX startY print 1 line StartX Start oMouseY House Lite Debug Lite Debug is an option available in the
322. thout a titlebar Window and Dialog Commands dialog open a dialog box dialog_modal open a modal dialog box dialog_nf open a dialog box without a frame dialog_nf modal open a modal dialog box without a frame dialog_fs open a dialog box the size of the screen dialog_nf_fs open a dialog box without a frame the size of the screen dialog_popup open a dialog box without a titlebar Window and Dialog Commands Controls Menus Buttons Etc Here are the details for Liberty BASIC commands that add menus buttons listboxes and more See also Understanding Syntax and Controls and Events and STYLEBITS Bmpbutton Button Checkbox Combobox Graphicbox Groupbox Listbox Menu Popupmenu Radiobutton Statictext Textbox Texteditor Control Descriptions A BMPBUTTON is a clickable button that displays an image Bmpbuttons allow users to give a command to a program Button A BUTTON is a clickable button with a text label Buttons allow users to give a command to a program M CheckBox A CHECKBOX is a small box that can be checked or unchecked by the user or by the programmer It displays a text label A checkbox is used when giving a user options from which to choose Combobox A COMBOBOX is a form of list It displays on the window as a small textbox with an arrow at the side When the user clicks the arrow the list drops down and the user can make a selection A combobox is appropriate when a program must give the user a
323. tn bmp colorGreen UL 75 bmmmpbur ton 1 mmh bluebrrn hmn TenlarRluel T 7 A file dialog will be displayed containing a list of TKN files Select the draw1 tkn file as shown and click on Ok Now the TKN application will run Liberty Draw Iof x Object Color Drawing Cie ry Programmers who have registered with the Gold License can also run the TKN file with the Runtime Engine Using the Runtime Engine Notice This part of the help file describes a feature of the registered version of Liberty BASIC Although the runtime engine described below does come with the shareware version it is only usable by registered users of Liberty BASIC who have purchased the Gold License When you register Liberty BASIC Shoptalk Systems will provide you with a password to upgrade your copy of Liberty BASIC to the registered version The RUN400 EXE runtime engine will allow you to create standalone programs from your Liberty BASIC TKN files This means that your programs can be run on computers that do not have the Liberty BASIC language installed To use the runtime engine you must have the gold license registered version of Liberty BASIC The runtime engine will automatically run a TKN file of the same filename as the runtime engine If you make a copy of RUN400 EXE named MYPROG EXE then you must name your TKN file as MYPROG TKN Using RUN400 EXE First make a TKN file from your BAS file see Creating a To
324. to issue the CLS command before new graphics drawing commands are issued print w g cls When this method is used the screen goes blank for an instant before new drawn items are displayed causing a flickering or blinking effect Segment and Delsegment It is possible to delete any segments that are no longer needed This method will not clear the graphics so no flickering effect will be visible Each segment has a number and each time a segment is closed with a FLUSH command the next segment has a number that is 1 greater than the last The first segment ID is 1 the second flushed segment ID is 2 the third is 3 and so on The number of the currently active segment is retrieved with the segment command print w g segment drawSegment This gets the segment number of the current segment and places it into the variable drawSegment Subtracting 1 from the current segment number will reference the last segment that has been FLUSHed It can then be deleted with the DELSEGMENT command as in this example print w g delsegment drawSegment 1 DISCARD The DISCARD command will remove any unflushed drawing commands An example is as follows demonstrate discard open Sine wave for graphics as sine print sine home down posxy x y print sine place 0 y width x 2 for x 0 to width print sine goto x y y sin x 40 next x print sine discard no redraw info kept wait end The p
325. to putitin Use this for things like values Printing columns with co for true and false file paths user preferences and Handle variables other stuff like that The old way The new way Subs for event handlers The old way The new way subs fc In the case of the special capitalized globals like S global true false font true 1 A funny example of re bien E te Mouse actions exam font times new roman 10 Global var Passing by reference Example of passing k Example of passing k iables call makeWindow print WindowWidth was changed W More about pass byr SSES Using maphandle sub makeWindow se The old way Ge W A New nranhics scrollbar HIJE b The left side of the lesson browser has a Table Of Contents TOC There are chapters and sections inside the chapters Clicking on one of the names in the TOC causes that part of the lesson to display The text or comments for the lesson will display in the upper right pane The comments can be scrolled if the text doesn t all fit in the pane Any accompanying code goes in the bottom right pane Choosing RUN either with the RUN button on the toolbar or the RUN command in the RUN menu causes the code in the code pane to be executed The code can be modified as desired and run multiple times Writing Lessons A new lesson can be created by selecting NEW from the FILE menu which offers the choice of
326. tor The Icon Editor can be found in the Setup menu Use it to create or modify icons and embed them into the runtime engine for your programs The icon editor can make new icons or open existing icon files It can save icons as icon files or it can replace the icon in the runtime engine with the icon viewed in the icon editor File Icon Color f Paint C Mask Making Icons Liberty BASIC requires 16 color icons Use the Icon Editor to create new icons or to modify existing icons To start from an existing icon choose Open Icon from the File menu To start a new icon either start drawing with the mouse by holding down the left mouse button and dragging or choose New Icon from the File menu to clear the Icon Editor and begin a new icon Ifthe lt Paint gt radiobutton is checked drawing will be opaque If the lt Mask gt radiobutton is checked drawing will will mark transparent areas of the icon These appear in the color cyan on the grid in the editor To change the color of the drawing choose the desired color from the Color menu Icons may be saved by choosing Save Icon from the File menu Changing the Runtime Icon The runtime engine is a copy of run exe that has been renamed to match the TKN for the program created with Liberty BASIC When you are finshed editing the icon in the icon editor you can insert it into the runtime engine by choosing Save to Runtime EXE from the File menu You don t need to sa
327. tract the position information out of our struct xOrg winRect orgX struct yOrg winRect orgY struct call the MoveWindow API to resize the window to a predefined siz calldll user MoveWindow _ hMain as long _ xOrg as long _ yOrg as long _ openingWidth as long _ expandedHeight as long _ 1 as boolean _ result as boolean WAIT hide get the window handle to a button in our Liberty BASIC window hndl hwnd main showMore call the ShowWindow API passing _SW_HIDE to hide the button calldll user ShowWindow _ hndl as long _ _SW_HIDE as long result as boolean WAIT quit close main close USER DLL close user END In the above example the program calls three APIs from USER32 DLL which is a standard Windows dynamic link library Here s what the code does 1 creates the structure winRect 2 opens USER32 DLL 3 gets the window handle for main a standard Liberty BASIC window 4 calls the GetWindowRect API to load the window position size into winRect 5 extracts the position information from the struct 6 calls the MoveWindow API to resize the window to a predefined size 7 gets the window handle to a button in the Liberty BASIC window 8 calls the ShowWindow API passing _SW_HIDE to hide the button 9 closes USER32 DLL See also CALLDLL STRUCT Using Types with CALLDLL What are APIs DLLs Example Programs For some examples showing how to call APIs examine the prog
328. tring c liberty summary txt into fileName If on the other hand Cancel was clicked then an empty string would be placed into fileName Program execution would then resume Be sure to trap this possibility in your programs or an error could occur filedialog Open text file txt fileNamesS if fileName lt gt then open fileNameS for input as f do stuff close f else notice No file chosen end if FILES Description The FILES statement collects file and directory information from any disk and or directory and fills a double dimensioned array with the information It is also good for determining if a specific file exists see below Usage dim arrayName 10 10 files pathSpecS arrayNamesS or files pathSpec arrayName you must predimension the array infoS even though FILES will redimension it to fit the information it provides dim info 10 10 files c infost The above FILES statement will fill info in this fashion info 0 0 a string specifying the qty of files found info 0 1 a string specifying the qty of subdirectories found info 0 2 the drive spec info 0 3 the directory path Starting at info 1 x you will have file information info 1 0 the file name info 1 1 the file size info 1 2 the file date time stamp Knowing from info 0 0 how many files we have call it n we know that our subdirectory information starts at n
329. ts the background for sprites to be the loaded bitmap called BmpName BACKGROUNDXY print w g backgroundxy 25 20 OR x 25 y 20 print w g backgroundxy x WR This places the point x y from the background bitmap at location 0 0 of the sprite graphicbox or graphics window CENTERSPRITE print w g centersprite SpriteName This causes a sprite s x y location to refer to the center of the sprite rather than the default upper left corner CYCLESPRITE print w g cyclesprite SpriteName 1 print w g cyclesprite SpriteName 1 print w g cyclesprite SpriteName 1 once This causes a sprite to cycle through its image list automatically Using 1 will cause the list to cycle forward Using 1 will cause the list to cycle backwards Using the optional once parameter will cause the sprite to cycle through its image list only one time other wise it cycles continuously DRAWSPRITES print w g drawsprites This causes all visible sprites to be drawn on the background and it updates the display REMOVESPRITE print w g removesprite SpriteName This causes the named sprite to be removed from the collection of sprites SPRITECOLLIDES print w g spritecollides SpriteName input w g lists OR print w g spritecollides SpriteName list This causes a list of all sprites that collided with the sprite named SpriteName to be contained in the variable called list SPRITEIMAGE print w g sprit
330. ty BASIC programs with subroutine handlers nomainwin button 1 amp Ok quit UL 120 90 40 25 checkbox 1 cb I am a checkbox checkSet checkReSet 10 10 1 30 20 textbox 1 text 10 90 100 24 WindowWidth 180 WindowHeight 160 open Checkbox test for dialog as 1 print 1 trapclose quit inputLoop input r sub checkSet cbHandle print cbHandleS value vs print 1 text I am v end Sub sub checkReSet cbhHandle print cbHandle value vs print 1 text I am v end Sub quit close 1 end CHR n Description This function returns a one character long string consisting of the character represented on the ASCII table by the value n 0 255 Usage print chr 77 print chr 34 print chr 155 Produces M H CLOSE h Description This command is used to close files and devices This is the last step ofa file read and or write operation and it is also used to close windows or DLLs that have been opened When execution of a program is complete if there are any files or devices left open Liberty BASIC displays a dialog explaining that it was necessary to close the opened files or devices This is designed as an aid so that the programmer can correct the problem If for some reason the programmer chooses to terminate the program early this is done by closing the program s main window before the program finishes then Liberty BASIC will cl
331. ty BASIC will load the draw1 bas program you selected The result will look like this window This is BASIC code for a Windows drawing program As you learn to program in Liberty BASIC you will be able to extend this program and the other included samples to do what you want But right now let s see how it runs Liberty BASIC v4 0 draw1_bas OF x File Edit Run Setup Help Die U DH ew BB Ze nomainwin lineThickness 1 menu 1 Object cLine setForLine Ellipse se menu 1 Color sRed colorRed Cello colorYell menu 1 Drawing Line Thickness lineThickness bmpbutton 1 bmp redbttn bmp colorRed UL 5 5 bmpbutton 1 bmp yllwhttn bmp colorYellow UL 4 bmpbutton 1 bmp grnbttn bmp colorGreen UL 75 hrmnhiut t on 1 hrmnihlueht tn brn TenlarRluel T d Ready Running a Liberty BASIC program is easy Select the Run menu and mouse click on the Run item as illustrated below You can also run a program by clicking the button on the toolbar that looks like a blue running man or by pressing the Shift key and leaving it down while pressing the F5 key Liberty BASIC 4 0 draw1_bas OF EX File Edit Run Setup Help lo Q O Debug Alt F5 A Lite Debug Ctri F5 Kill BASIC Programs Go to Branch Label Alt G Make TKN File Run TKN File 1 Release notes Gi E AB love H setForLine Ellipse se colo
332. ual frog images To see how to make Liberty BASIC cycle through these images when drawing the frog sprite see the section on Sprite Properties Bitmaps can be used multiple times within one sprite designation Note that frog2 is used twice here print w g addsprite frog frogl frog2 frog3 frog2 ACCESSING INDIVIDUAL IMAGES FROM SPRITE LIST In the example above the frog sprite consists of three separate frog images By default the first image is shown when the sprite is drawn To show any image from the list the SPRITEIMAGE command is issued specifying the image name to be used In the following example when the sprite is drawn after this command it will be drawn as the frog2 image In this manner the image can be changed at any time print w g spriteimage frog frog2 The individual images of a sprite can be cycled automatically by issuing a CYCLE command which is discussed along with other sprite properties in Sprite Properties IMPORTANT To avoid flickering sprite animation is done invisibly in memory A frame of animation is built entirely off screen A frame of animation is displayed on the screen only when the command DRAWSPRITES is called For each frame of animation perform all functions to set the background image and to set or change a sprite s properties then call the DRAWSPRITES command Learn about updating the display in Drawing adn Collision Detection Sprite Properties Sprite properties include
333. uct as well as in OPEN statements ASC s ascii value of s ASN n arc sine of n ATN n arc tangent of n lautoresize texteditor command to relocate control automatically autoresize graphics command to relocate control automatically backcolor graphics command to set background color background sprite command to set background image backgroundxy sprite command to set background position BackgroundColor sets or returns background color for window BEEP play the default system wave file BINARY purpose parameter in fileopen statement Bitwise Operations modify bit pattems inan oject BMPBUTTON add a bitmap button to a window BMPSAVE save a bitmap to a disk file BOOLEAN evaluates to true or false box graphics command to draw box boxfilled graphics command to draw filled box BUTTON add a button to a window BYREF passes an argument to a subroutine or function by reference CALL call a user defined subroutine CALLBACK address of a callback function CALLDLL call an API or DLL function CASE specifies a value for select case statement centersprite causes the x y location of a sprite to be its center CHECKBOX add a checkbox to a window CHR n return character of ascii value n circle graphics command to draw circle circlefilled graphics command to draw filled circle CLOSE h close a file or window with handle h CLS clear a program s mainwindow cls graphics command to clear drawing area Icls text
334. ult button in a DIALOG window If a control other than a button has the focus the button whose extension is default is the default button if such a button exists Button commands print handle ext string This command changes the text displayed on the caption of the button string may be a literal string of text enclosed in quotes or a string variable print handle ext setfocus This command causes the button to receive the input focus This means that any keypresses will be directed to the button print handle ext locate x y width height This command repositions the button control in its window This only works if the control is placed inside window of type window or dialog The control will not update its size and location until a refresh command is sent to the window See the RESIZE BAS example program print handle ext font facename pointSize This command sets the button s font to the specified face and point size If an exact match for the font face and size is not available on the user s system then Liberty BASIC will try to finda close match with size taking precendence over face There is more information on specifying fonts here How to Specify Fonts Example print handle ext font times new roman 10 print handle ext enable This causes the control to be enabled print handle ext disable This causes the control to be inactive and grayed out print handle ext show This cau
335. unction returns the greater of two numeric values Usage input Enter a number a input Enter another number b print The greater value is max a b MIN expr expr2 Description This function returns the smaller of two numeric values Usage input Enter a number a input Enter another number b print The smaller value is min a b RND number Description This function returns a random number between 0 and 1 The number parameter is usually set to 1 but the value is unimportant because it is not actually used by the functoin The function will always return an arbitrary number between 0 and 1 Usage print ten numbers between one and ten for a 1 to 10 print int rnd 1 10 1 next a RANDOMIZE n Description This function seeds the random number generator in a predictable way The seed numbers must be greater than 0 and less than 1 Numbers such as 0 01 and 0 95 are used with RANDOMIZE Usage this will always produce the same 10 numbers randomize 0 5 for x 1 to 10 print int rnd 1 100 next x Trigonometry Tip There are 2 pi radians in a full circle of 360 degrees A formula to convert degrees to radians is radians degrees divided by 57 29577951 Here are some helpful functions to convert degrees to radians radians to degrees and to calculate PI function pi pi asn 1 2 end function function rad2deg num rad2deg 90 asn 1 num end function
336. urned When a texteditor is first opened the result would be column 1 row 1 The result is contained in the variables columnVar and rowVar print handle origin column row This forces the origin of the texteditor to be column and row Row and column must be literal numbers To use variables for these values place them outside the quotation marks preserving the blank spaces like this print handle origin column row print handle paste This causes the text in the WINDOWS clipboard if there is any to be pasted into the texteditor at the current caret position print handle select column row This will put the blinking cursor caret at column row Column and row must be literal numbers To express them as variables place the variables outside the quotation marks and preserve the blank spaces like this print handle select column row print handle selectall This causes everything in the texteditor to be selected print handle selection selected This returns the highlighted text from the texteditor The result will be contained in the variable selected print handle setfocus This causes Windows to give input focus to this control This means that if some other control in the same windows was highlighted and active that this control now becomes the highlighted and active control receiving keyboard input print handle ext enable This causes the control to be ena
337. ut g lof g close g print txts end produces 12345 12345 Sequential Files Sequential files are opened with the OPEN statement When they are no longer needed or when the program ends they must be closed with the CLOSE statement Sequential file access allows data to be read from a file or written to a file from beginning to end It is not possible to read data starting in the middle of the file nor is it possible to write data to the file starting in the middle using sequential methods Data is read from a file opened for INPUT starting at the beginning of the file Each subsequent input statement reads the next piece of data in the file Data is written to a file opened for OUTPUT with a PRINT statement starting at the beginning of the file and each subsequent PRINT statement writes data to the end of the open file When a file is opened for APPEND each PRINT statement writes data to the end of the open file Sequential File Access INPUT Files opened for INPUT can be read from They cannot be written to A file opened for INPUT must exist on disk or the program will halt with an error See Testing For File Existence The INPUT statement reads a piece of data up to the next comma or carriage return The LINE INPUT statement reads a piece of data that contains commas that are not delimiters and stops reading data at the next carriage return The INPUTS statement reads data of a specified length from a file the INPUTTO st
338. uter to use only two digits 0 and 1 in its number system A byte is a group of eight bits and it is the standard unit by which data is stored There are 256 different combinations of zeros and ones you can make with one byte from 00000000 to 11111111 This is enough to cover all the ASCIl characters Binary Access The name given to the method of accessing the data in a file byte by byte Bit The smallest amount of information that can be transmitted Bit is short for binary digit A bit can be a zero or a one Bitmap An image stored in a disk file Bitmaps must be loaded into memory from the disk before they can be displayed Boot Starting your computer by turning on the power Border The edge of a window is called the border You can resize a window by clicking and dragging the border with the mouse Branch A conditional jump or departure from the implicit or declared order in which instructions are being executed Bug An error in a computer program Byte Consists of eight binary digits It is the smallest unit a computer works with at once The bits ofa byte can be individually modified but a computer still works with at least one byte at a time Click The act of pushing down and releasing the mouse button Clipboard A temporary storage area inside the computer It is used to copy or move data from one program to another or from one area of a document to another Close To close a program means to end a program C
339. utton handler button main exit Exit exitClicked UL 10 10 open Button Example for window as main loop wait exitClicked notice The Exit button was clicked Goodbye close main end This example uses a subroutine button handler button main exit Exit exitClicked UL 10 10 open Button Example for window as main loop wait sub exitClicked buttonhandle notice The button handle is buttonhandle Goodbye close main end end sub This example retrieves a value with an input statement button main ok Okay yes UL 10 10 button main cancel Cancel no UL 70 10 open Use Input Example for window as main main trapclose quit loop input answers if answerS yes then notice You clicked Okay if answer no then notice You clicked Cancel goto loop quit close main end Default Button A window of type DIALOG can contain a button with the extension default If the user presses the ENTER key while the dialog window has focus it is the same as if the button whose extension is default is pressed and program execution will continue at the event handler branchLabel for that button In the example below the program will branch to the okay routine when the user presses ENTER button win default Okay okay UL 200 100 open Test for dialog as win Change in behavior for LB3 If any button has focus it acts as the defa
340. ve it as an icon file first When an icon has been embedded within the runtime engine it will display in file lists in Windows Explorer it will appear if a desktop shortcut is created and it will appear in the titlebar of the running program Here is an example that starts with a copy of the runtime engine called freeform exe To install an icon which already been created Start Liberty BASIC if needed Click on the Setup menu and choose Icon Editor Click on the File menu in the Icon Editor and open the icon file named freeform ico To install the icon in the freeform exe file Click on File and then choose Write Icon To Module Find the freeform exe file in the file dialog that appears select it and click on Ok See also Using the Runtime Engine Lesson Browser Lesson Browser Setup Liberty BASIC includes a lesson browser The lesson browser has the ability to link tutorials and comments with executable code making it a perfect venue for creating lessons and demonstration programs Ifa file selected with OPEN from the FILE menu has an extension of Isn it will open in the lesson browser Here is the Liberty BASIC lesson browser in action Liberty BASIC v4 0 C Program Files Liberty File Edit Run Setup Help Deg ai al sele ei a 7 Introducing LB4 alpha 1 si don t recommend the liberal use of global variables A Improvements to DIM but the overwhelming demand for this feature Print TAB prompted me
341. ver facename in the match For more on specifying fonts read How to Specify Fonts Example print handle font Times New Roman 10 print handle insert varname This inserts the contents of the variable at the current caret text cursor position leaving the selection highlighted print handle line n string This returns the text at line n n is standing in for a literal number If nis less than 1 or greater than the number of lines the texteditor contains then an empty string is returned After this command is issued the specified line s text is contained in the variable string print h lines countVar This returns the number of lines of text contained in the texteditor placing the value into the variable countVar print handle ext locate x y width height This repositions the control in its window This is effective when the control is placed inside window of type window The control will not update its size and location until a REFRESH command is sent to the window See the RESIZE BAS example program print handle modified answer This returns a string either true or false that indicates whether any data in the texteditor has been modified The variable answer holds this returned string This is useful for checking to see whether to save the contents of the texteditor before ending a program print h origin columnVar rowVar This causes the current texteditor origin to be ret
342. w in a graphics window using the font Arial 14 point italic open Font example for graphics as fontExample print fontExample trapclose quit print fontExample down print fontExample font arial 14 italic print fontExample This is Arial 14 point italic wait quit close fontExample end In the above example the line print fontExample font arial 14 italic contains a font specification Everything after the word font is the specifier arial 14 italic Sending Font Commands to Text Controls The font command is preceded by an exclamation point character when sent to controls that allow text to be printed to them such as a textbox control or statictext control The character signals Liberty BASIC to send a command to the control rather than print a new text string on it Font Specifications FaceName The facename is case insensitive so Arial is the same as ARIAL and arial To specify a font which has spaces in its name use underscores like this Courier New becomes Courier_New or ignore the uppercase letters and type courier_new Size in Points Specify a point size as above by using a single size parameter A point is 1 72 of an inch so there are 72 points in an inch A font that is 14 points high is not the same size as a font that is 14 pixels high Size in Pixels To specify font size by pixel rather than by point include parameters for both width and he
343. w promoted to true global variables Until now these could only be set in the main part of the program not in functions and subroutines That limitation has now been lifted See the code below for examples of this Example one global true false fonts true 1 false 0 font times new roman 10 call makeWindow print WindowWidth was changed WindowWidth wait sub makeWindow if true lt gt false then notice Hey true isn t the same as false Whatta ya know end if WindowWidth 350 texteditor main tel 8 8 250 152 textbox main tbl 16 192 112 24 statictext main Statictext4 Font Name w h 8 168 100 18 button main applyl Apply applyFont1l UL 136 192 67 24 radiobutton main rbl Radiobutton 1 set clear 16 226 190 20 checkbox main cbhl Checkbox 1 set clear 16 256 190 20 open Untitled for window as main main font fonts main tel The font is font end sub Example two define a global string variable global titles title Great Program Special system variables don t need to be declared as global since they have that status automatically BackgroundColors darkgray ForegroundColor darkblue call my subroutine to open a window call openIt wait sub openIt statictext it stext Look Mom 10 10 70 24 textbox it tbox 90 10 200 24 open title for window as it print it tbox No hands end sub
344. wHeight 180 open Select a contact status for window as status S wait tatus list singleclickselect sub selectionMade handle print status list selection selections notice selectionS was chosen with listbox handle end sub cancelStatusSelection notice Status selection cancelled close status end For information on creating controls with different background colors see Colors and the Graphical User Interface LOADBMP LOADBMP name filename bmp and LOADBMP name hbmp Description The first version of this command loads a standard Windows BMP bitmap file on disk into Liberty BASIC The name is a string chosen to describe the bitmap being loaded and the filename bmp is the actual name of the bitmap disk file Once loaded the bitmap can then be displayed in a graphics window type using the DRAWBMP command see Graphics Window Commands Usage loadbmp copyimage bmp copy bmp open Drawbmp Test for graphics as main print main drawbmp copyimage 10 10 wait when program exits unloadbmp copyimage The second version of the command loads the bitmap whose handle is referenced by hbmp This handle can be obtained from an add on DLL that loads images such as the nviewlib dll or by creating a bitmap using API calls or by loading a bitmap with the API function LoadimageA Add on DLLs allow you to access images in other formats such as jpg or gif and then load them
345. wave file to finish playing loop play the wave file over and over cancel with playwave Usage playwave ding wav async playwave tada wav playwave hello wav loop playwave to stop previous wav from playing POPUPMENU POPUPMENU text branchLabel text2 oranchLabel2 Description This command pops up a Windows menu The upper left corner of the menu will be positioned where the cursor is located when the command is issued Each text branchLabel pair after the title adds a menu item to the menu and tells Liberty BASIC where to branch to when the menu item is chosen The character can optionally be placed between menu items to cause a separating line to be added between the items when the menu is popped up The amp character placed in the text items for the menu specifies the accelerator placement for each item The letter directly following the amp character will act as a hotkey for that menu item when it is pressed while the user presses and holds down the ALT key The hotkey appears underlined in the menu display The menu command is written on a single line It may be displayed in multiple lines for viewing if the continuation character _ is used Here is an example of a graphics window with a popupmenu nomainwin open Geometric White board for graphics nsb as geo print geo trapclose quit print geo when rightButtonUp popupMenu wait stop and wait for a menu
346. window as 1 1 te this is the first window 1 trapclose aboutToClosel texteditor 2 te 10 10 200 200 open text second for window as 2 2 te this is the second window 2 trapclose aboutToClose2 texteditor 3 te 10 10 200 200 open text third for window as 3 3 te this is the third window 3 trapclose aboutToClose3 wait aboutToClosel confirm Close first answer if answer 1 then close 1 wait aboutToClose2 confirm Close second answer if answer 1 then close 2 wait aboutToClose3 confirm Close third answer if answer 1 then close 3 wait MENU 2 Window Title Menu Title Edit Menu ltem lt MENU handle title text branchLabel text2 branchLabel2 or MENU handle title text subName1 text2 subNamez Description This command adds a pull down menu to the window at handle The item title specifies the title of the menu as seen on the menu bar of the window and each text branchLabel pair after the title adds a menu item to the menu and tells Liberty BASIC where to branch to when the menu item is chosen A sub can be used as a menu event handler The character can optionally be placed between menu items to cause a separating line to be added between the items when the menu is pulled down The amp character placed in the title and text items for the menu specifies the accelerator placement for each it
347. window to open WindowHeight specifies the height of the next window to open WINSTRING ptr returns string from ptr WORD data type for calldll and structs WORD s n returns nth word from s XOR logical and bitwise XOR operator Command Reference A C D F G K L M N P R S T Z Additional Commands Text Commands a detailed summary of text window commands in Liberty BASIC Graphics Commands a detailed summary of graphics commands in Liberty BASIC Sprite Commands a detailed summary of sprite commands in Liberty BASIC Reserved Word List The names of commands and functions are called reserved words These include familiar commands and functions like PRINT INPUT CHR and many others Function names include the opening parenthesis You cannot use reserved words to name variables subroutines or functions When you write software using Liberty BASIC you are not required to capitalize reserved words There are some built in variables that are recognized by Liberty BASIC These are listed at the bottom of the page Do not use these variable names for your own purposes Reserve their use as intended by Liberty BASIC The list of reserved words in Liberty BASIC COMMANDS AND APPEND AS BEEP BMPBUTTON BMPSAVE BOOLEAN BUTTON BYREF CALL CALLBACK CALLDLL CALLFN CASE CHECKBOX CLOSE CLS COLORDIALOG COMBOBOX CONFIRM CURSOR DATA DIALOG DIM DLL DO DOUBLE DUMP DWORD ELSE END ERROR EXIT FIELD FILEDIALOG FILES FONTDIA
348. wise it returns 1 The length of a file can be retrieved with the LOF function The drive specifications for the computer on which a program is running are contained in the special variable Drives The directory in which a program resides on disk is contained in the special variable DefaultDir Folders also called Directories can be created with the MKDIR command Folders also called Directories can be removed with the RMDIR command Different Methods of File Access Sequential Files Sequential Files are accessed from beginning to end sequentially It is not possible to read or write a piece of data to the center of the file Files opened for INPUT can only be read Files opened for OUTPUT or APPEND can only be written For more see Sequential Files Binary Files Files opened for binary access may be read or written beginning at any location within the file For detailed information on using binary files see Binary Files Random Files Files opened for random access are read or written one record at a time The length of records in the file is determined in the OPEN statement For detailed information on using random files see Random Access Files String and Numeric Data All data whether strings of text or numbers is printed as ASCII text characters in files as the following example illustrates open test txt for output as f print f 12345 print f 12345 close f open test txt for input as g txt inp
349. with a good working knowledge of calling API functions with CALLDLL A CALLBACK command sets up a memory address for the function specified in the command An API function can then use this address to call the specified function many times hence the term CALLBACK Most API functions are called once and return a single value A CALLBACK function interacts with the program many times The parameters are explained in more detail below Usage addressPTR This parameter assigns a name to the memory address of the function This name is used in the API call that requires the memory address functionName This parameter is the name of the function in the Liberty BASIC program that is called by the API function type type2 The CALLBACK statement requires a comma separated list of parameters is specific to the function used Most Windows API references contain documentation for the particular functions available The parameters must be valid data TYPES such as ulong and long returnValue The TYPE of the return value is listed after the closing parenthesis The Liberty BASIC function can return a value to the calling function In the following demo the Liberty BASIC function keeps an internal count and returns 1 if it is continuing to process information and 0 when it returns control to the calling function It prints the names of the first 5 windows that are sent to it by the EnumWindows API then returns control to the calling fun
350. with the handle myWindow continuing execution of the program there if the user tries to close the window see buttons1 bas example below If the subroutine subLabel is designated as the event handler rather than a branch label the named subroutine is executed when the close event is triggered The handle of the window is passed into the subroutine by Liberty BASIC Usage with branch label handler The trapclose code in buttons1 bas looks like this open This is a turtle graphics window for graphics nsb as 1 print 1 trapclose quit stop and wait for buttons to be pressed wait And then the code that is executed when the window is closed looks like this quit confirm Do you want to quit Buttons quits if quitS no then wait close 1 end Usage with subroutine handler The trapclose code in buttons1 bas would look like this if a subroutine was used as the handler open This is a turtle graphics window for graphics nsb as 1 print 1 trapclose Quit stop and wait for buttons to be pressed wait And then the code that is executed when the window is closed looks like this sub Quit handle confirm Do you want to quit Buttons quits if quitS no then wait close handles end end sub Colors and the Graphical User Interface By default Liberty BASIC gives windows and controls standard colors from the user s Windows Control Panel settings Several special variables are provided to change the
351. without drawing Any other drawing commands will simply be ignored until the pen is put back down print handle vertscrollbar on off min max This command manages the vertical scrollbar If the value is on the scrollbar is visible If the value is off the scrollbar is not displayed Ifthe optional paramters for min and max are used they set the minimum scrollbar range and the maximum scrollbar range in pixels A large scrollbar range allows the graphics window to scroll a long distance while a short range allows it to scroll a short distance print handle when event eventHandler This tells the window to process mouse and keyboard events These events occur when a user clicks double clicks drags or just moves the mouse inside the graphics window An event can also be the user pressing a key while the graphics window or graphicbox has the input focus see the setfocus command above This provides a really simple mechanism for controlling flow of a program which uses the graphics window The eventHandler can be a valid branch label or the name of a subroutine See also Controls and Events Sending print handle when leftButtonDown startDraw to a graphicbox or graphics window will tell that window to force a goto startDraw if the mouse is inside that window when the user presses the left mouse button Sending when leftButtonDown startDraw to a graphics window or graphicbox tells the window to call the subroutine startDraw
352. wo 2 three 3 end 0 end Error Handling If you try to read more DATA items than are contained in the DATA lists the program will halt with an error Notice that in the examples above an end tag is placed in the DATA and when it is reached the program stops READing DATA This is an excellent way to prevent errors from occurring If an end tag or flag of some sort is not used be sure that other checks are in place to prevent the READ statement from trying to access more DATA items than are contained in the DATA statements See also DATA RESTORE READ and DATA READJOYSTICK READJOYSTICK 1 or READJOYSTICK 2 Description You can read the position of up to two joysticks and their buttons The readjoystick command reads the x y and z of an installed joystick proper drivers must also be installed and also their buttons The variables are visible everywhere because they are global Usage readjoystick 1 The command above reads the current status of joystick 1 and places the values into these global variables Joy1x Joy1ly Joy1z Joy1button1 Joy1button2 readjoystick 2 The command above reads the current status of joystick 2 and places the values into these global variables Joy2x Joy2y Joy2z Joy2button1 Joy2button2 REDIM Description This redimensions an already dimensioned array and clears all elements to zero or to an empty string in the case of string arrays This can be very useful for writing applicatio
353. wo blocks in this example One is executed if qtySubdirs 0 and one is executed if qtySubdirs is not equal to 0 Only one of the two blocks will be executed never both as a result of the same test These conditional blocks can be nested inside each other if verbose 1 then if qtySubdirs 0 then print None else print Count of subdirectories qtySubdirs end if end if In the example above if the verbose flag is set to 1 true then display something or else skip the display code entirely See also Select Case Conditional Statements Boolean Evaluations Inkey Keyboard input can only be trapped in graphics windows or graphicboxes When a key is pressed the information is stored in the variable Inkey Description This special variable holds either a single typed character or multiple characters including a Windows virtual keycode Notice that because Inkey is a variable it is case sensitive Remember that at this time only the graphics window and graphicbox controls can scan for keyboard input The virtual keycodes are standard Windows constants and include arrow keys function keys the ALT SHIFT and CTRL keys etc If Inkey is a single character that character will be the key pressed See the section below for a description of Inkey when len Inkey is greater than 1 INKEY BAS how to use the Inkey variable open Inkey S example for graphics as graph print graph when characterInput fetch
354. xonemn sco E O Dayo k Eet RIsonenm moe wl Cem QUIS sev E sOOekwss Om OXOOMOxXm I JOOSA xem ODOM 0 2XOmMm Om Josue Joo OMHSOm2 HOM SOOM 2 EN Qojmemoeono z AXEOOWN S SXESOW Ate EZ eis S Se0h amp sOme2kKexXKOmsser AS Resto ZBA A00 QO S Gm EZ E A EE ZB Siem E B SOGO ZB Wl DT Se mt Edel H Sss e extmey Yev SPLOH mxaomem S Oo sew wa DEL 966 ili mp eg SORTIE BOA SA SMAS NR GDIOOgeRAT 25 sao E O es Jaa GT Z r Y22 KOxXOmSc e G IOOGcRZ aw aw oo ee yels B EEN gt O0bISOOXE vme OZEN soassa Ven sea Q OA Soke Skee Fes E E ZO Lowe mote Moe AXESOAW SMMM e AKA z AKAM HD O CIg ASP APH OAA AbpO edsys M It 2 o C Ip 3 LI QO Hee 2 H Acoma sNiLer LOHeOaDKm sHoeO Ws AROS EB SES LEM SJAOLOG BE SSO BO BS Proe T E 0 ZB MHOMen Keen lt ZS
355. xt statement after a GOSUB command was issued RETURN is the last statement in a block of code that is called by the GOSUB command See GOSUB RIGHT s n RIGHT string number Description This function returns a sequence of characters from the right hand side of the string string variable or string expression string using number to determine how many characters to return If number is 0 then an empty string is returned If number is greater than or equal to the number of characters in string then string will itself be returned Usage print right I m right handed 12 Produces right handed And print right hello world 50 Produces hello world Note See also LEFT and MID RMDIR Description The RMDIR function attempts to remove the directory specified If the directory removal is successful the returned value will be 0 If the directory removal was unsuccessful a value indicating a DOS error will be returned Usage remove a subdirectory named pigseye in the current root directory result rmdir pigseye if result lt gt 0 then notice Temporary directory not removed Note See also MKDIR RND n Description This function returns a random number between 0 and 1 The number parameter is usually set to 1 but the value is unimportant because it is not actually used by the functoin The function will always return an arbitrary number between 0 and 1 Usage prin
356. y are released Virtual Keys A virtual key is the key that is actually pressed on the keyboard The VK value for a letter say a is the same for lower case a and upper case A because it refers to the key pressed on the keyboard not to the ASCII value of the input Most keys have a graphical representation Pressing the a key in a text window causes the letter a to be displayed in the window There are some keys that do not have a graphical representation It is necessary to use Virtual Key Codes to discover which of these keys has been pressed They include the arrow keys the F keys Shift Ctrl Alt Del etc Here is a program that gives a quick example Inkey example part two ctrl chr _VK_CONTROL print Keys pressed open Inkey example for graphics as graph print graph when characterInput keyPressed print graph trapclose quit loopHere make sure graph has input focus print graph setfocus scan for events scan goto loopHere keyPressed key leftS InkeyS 2 if len key lt 2 then print pressed keyS else if right key S 1 ctrl then print CTRL was pressed else print Unhandled special key end if end if goto loopHere quit print Quitting close graph end Some other virtual key code constants Error Messages Sometimes when using Liberty BASIC there are error messages presented while compiling called compile time errors and while running a
357. y expression at all each separated by a semicolon Each expression is sent in sequence Printing can be formatted into columns with the TAB n function When you are finished sending data to the printer you should commit the print job by using the DUMP statement Liberty BASIC will eventually send your print job but DUMP forces the job to finish Usage lprint hello world This prints hello world dump lprint hello This also prints hello world lprint world dump age 23 lprint Ed is age years old This prints Ed is 23 years old dump Note see also PRINT DUMP PRINTERDIALOG TAB n MAINWIN MAINWIN columns rows Description This sets the width or width and height of a program s main window This is specified in colums and rows of text according the font of the mainwindow This statement is usually placed at the beginning of the program code Usage set a width of 40 columns mainwin 40 Or set the width to 40 columns and height to 12 lines mainwin 40 12 See also NOMAINWIN MAX MAX expr1 expr2 Description This function returns the greater of two numeric values Usage input Enter a number a input Enter another number b print The greater value is max a b See also MIN MAPHANDLE maphandle oldHandle newHancle maphandle oldHandle newHandle Description Maphandle assigns a new handle to a device after it is open Nowit is possible to reuse cod
358. y type select case with no variable or expression after it In the following example since value evaluates to the first CASE statement the printout says First case correct value 58 select case case value lt 10 or value gt 50 and value lt 60 print First case case value gt 100 and value lt 200 print Second case case value 300 or value 400 print Third case case else print Not evaluated end select If the expression value is placed after select case then none of the CASE statements is met so CASE ELSE is triggered which prints Not evaluated incorrect usage if multiple cases must be evaluated select case value Nested statements Nested select case statements may be used Example select case atb case 4 5 select case c d case 100 do stuff end select do stuff case 6 7 do other stuff end select See also if then SIN n Description This function returns the sine of the angle n The angle n should be expressed in radians Usage for t 1 to 45 print The sine of t is sin t next t Tip There are 2 pi radians in a full circle of 360 degrees A formula to convert degrees to radians is radians degrees divided by 57 29577951 Note See also COS and TAN SORT SORT arrayName start end column Description This command sorts both double and single dimensioned arrays The start parameter specifies the element with whi
359. you to type an expression to evaluate ask for an expression input Type a numeric expression gt codeS answer eval code print answer FIELD h list FIELD handle length1 as varName lenght2 as varName Description FIELD is used with an OPEN filename ext for random as handle statement to specify the fields of data in each record of the opened file For example in this program FIELD sets up 6 fields of data each with an appropriate length and associates each with a string variable that holds the data to be stored in that field open custdata 001 for random as cust len 70 open as random access field cust 20 as name 20 as street 15 as city 2 as state 10 as zip 3 as age inputLoop input Name gt nameS input Street gt streets input City gt citys input State gt states input Zip Code gt zips input Age gt age confirm Is this entry correct yesNo ask if the data is entered correctly if yesNoS no then inputLoop recNumber recNumber 1 add 1 to the record and put the record put cust recNumber confirm Enter more records yesNo ask whether to enter more records if yesNo yes then inputLoop close cust end of program close file end Notice that Liberty BASIC permits the use of numeric variables in FIELD eg age and it allows you to PUT and GET with both string and numeric variables automatically without needing LSET RS
360. ze byref word word upper left word 1 mid word 2 end sub More about pass by reference Passing by reference is only supported using string and numeric variables as parameters You can pass a numeric or string literal or a computed number or string or even a value from an array but the values will not come back from the call in any of these cases Step through the example in the debugger to see how it works you can also call without variables but the changes don t come back result formatAndTruncateXandY 7 2 5 3 print results and it works with subroutines too call capitalize gandalf a 0 snoopy call capitalize a 0 end function formatAndTruncateXandY byref a byref b a int a b int b formatAndTruncateXandy str a str b end function sub capitalize byref words wordS upperS left word S 1 mid word 2 end sub CALL call subroutineName list of zero or more comma separated values Description This command invokes a user defined subroutine Call is followed by the name of the subroutine and by zero or more string and or numeric expressions For more information see SUB CALLBACK Description A Callback is the address of a program function that is used as a parameter in API call The syntax is callback addressPTR functionName type1 type2 returnValue Note Callbacks are an advanced programming technique They should only be used by programmers

Liberty Basic Manual - Epping Boys High School

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