Combining graphics with TeX on PC systems with laser printers, part II
Contents
1. 1990 6 Donald E Knuth The TpXbook pages 228 229 Addison Wesley Publishing Company 1986 ISBN 0Q 2 1 13448 9 5 on Hewlett Packard Corporation Boise Division P O Box 15 Boise Idaho 83707 December 1986 Part No 33440 90901 8 David Fuchs TgX Font Metric Files TUG boat 2 1 12 17 1981 9 Tomas Rokicki Packed PK Font File Format TUGboat 6 3 115 120 1985 10 TEXPRINT PS User Guide Oregon House Software Inc 12894 Rices Crossing Road Ore gon House CA 95962 1988 Lee S Pickrell Wynne Manley Software Inc C o Micro Programs Inc 251 Jackson Ave Syosset NY 11791 516 921 1351 Resources Data General Site Report Bart Childs The distribution with the new versions of TEX and METAFONT is nearly finished We are also rewriting the drivers for the DG QMS and LaserJet printers in Silvio Levy s CWEB We have decided to use Tom Rokicki s PostScript drivers Bart Childs Dept of Computer Science Texas A amp M University College Station TX 77843 3112 bart cssun tamu edu2. cept that the positioning commands have not been removed from the image file The frame has again been drawn where TEX thinks the graphic is located However because the graphics file was not properly processed additional positioning commands remain and the image is offset The example shown in Figure 2 is relatively be nign The positioning sequences in the graphics file specified a relative position so the image is offset somewhat from the position of the special com mand However it is more common to find abso lute positioning commands in graphics files These commands simply place the graphic image at some fixed location on the page and ignore entirely the present cursor position 7 Therefore there would be no correlation at all between the actual location TUGboat Volume 11 1990 No 2 of the graphics and where TEX thinks the graphics are located All of the application programs we have tested which provide LaserJet graphics have used absolute positioning commands This choice is logical An application program has no way of knowing a pri ori the location of the LaserJet cursor Attempting to write the graphics at the present cursor location would be dangerous because the graphics could ap pear anywhere on the page Conversely the devel opers of these programs probably want the graphics to be somewhat centered and they can control the graphics position unambiguously with absolute co ordinates E The pr
3. 7900 415 961 4400 16 January 1989 6 PostScript Language Reference Manual Ap pendix C Structuring Conventions Adobe Sys tem Inc Addison Wesley Publishing Co Inc 1985 p 268 Len Schwer APTEK Inc 4320 Stevens Creek Blvd Suite 195 San Jose CA 95129 micro2 schwer sri com TUGboat Volume 11 1990 No 2 Combining Graphics with T X on PC Systems with Laser Printers Part II Lee S Pickrell Abstract In this article we will extend our premise that TREX affords an excellent mechanism for combining graph ics in T X documents We propose a method for in cluding graphics that brings to bear the full power and versatility of T X for positioning the graphics as well as the text The technology for implement ing this feature will be discussed including certain limitations We will also consider possible benefits of file conversion utilities particularly the potential advantage of converting graphics to the PK TFM file format of TeX fonts One application of this fea ture is that the captured graphics can be used with PostScript drivers This technique can significantly increase the number of graphics sources available to PostScript based TpX by accessing applications that support the LaserJet PCL language Finally screen capture will be examined as an adjunct to printer capture in the case that printer capture is not prac tical 1 Introduction and review In our first article 1 we made several
4. assertions in particular that TEX provided a natural platform for mixing graphics with typeset text Several graphic plots were included that were obtained from differ ent application programs several more will be in cluded in this article which we hope substantiated our assertions e TEX provides a natural platform for graphics in sertion certainly comparable to any other word processing system o TEX has suffered from a perception that it does not handle graphics well probably grounded more in psychology than technical reality and possibly due to the broad spectrum of comput ing systems and distinct device driver programs over which TEX is implemented e The IBM PC and LaserJet printer are the logi cal starting place for demonstrating the graph ics capabilities of TeX because graphics appli cations for the PC LaserJet combination have become ubiquitous e Printer output capture is the best method for obtaining graphics images because the available resolution is much higher than screen capture and the number of graphics sources is much larger than file conversion TUGboat Volume 11 1990 No 2 2 Graphics positioning bringing the full power of TEX to bear The thesis of this article and the premise of the CAPTURE design is that x graphics images should be manipu ZA lated by TEX with the same facility W that typeset text is positioned This assertion is both practical and con sistent with the T X design ph
5. center the plot in the current TREX context Because TUGboat is typeset in a two column format the image is centered in a column as it should be However if this same arti cle were typeset in a single column format the plot would be automatically centered in a page The insertplot command also contains the special command which instructs the device driver to load and print the graphics file at the present cursor location In order for the graphic to be positioned properly inside the hbox inside the frame the location of the graphic must be well defined with respect to the special command and the special command must have a well defined location inside the box Fortunately the definition of the special command from Knuth 6 specifies that it will have a unique well defined location on the page Therefore it is implicitly associated with a particular position on the page namely the refer ence point that would have been present if a box of height depth and width zero had appeared in place of the whatsit 6 If the position of the graphic is linked to the location of the special command it will also have a well defined location that can be placed inside the hbox The technology for connecting the graphics to the special command is based on the LaserJet command structure The LaserJet PCL language contains a control code which says in effect start the graphic at the present cursor location 7 If the graphics
6. example and proof of principle that the graphics capability of T X is considerable We would like to propose hopefully without being presumptuous that other graphics implementation programs adopt some of the ideas discussed here For example e TEX should be able to manipulate graphics im ages equivalently to fonts of type e A graphics program for TEX should support the PK TFM format to maintain the greatest pos sible device independence In this way the distinction between graphics and text in TEX should be diminished and a connection between the various implementations of T X can be maintained by the device independent nature of the standard TEX formats References 1 Lee S Pickrell Combining Graphics with TpX on IBM PC Compatible Systems with LaserJet Printers TUGboat 11 1 26 31 1990 2 Leslie Lamport ATEX A Document Prepara tion System Users Guide amp Reference Manual Addison Wesley Publishing Company Read ing Mass 1986 ISBN 0 201 15790 X 3 Donald E Knuth The TgXbook Addison Wesley Publishing Company 1986 ISBN 0 2 1 13448 9 7 LaserJet series II User s Manual TUGboat Volume 11 1990 No 2 4 David G Cantor DROP STY Published in TeXhax number 16 1988 Available on the Clarkson Archive Server public domain CAPTURE A Program for Including Graph ics in TEX Wynne Manley Software Inc 1094 Big Rock Loop Los Alamos NM 87544 March
7. file contains this control code then the image will be inserted starting at the location of the special command which is well defined and will be centered inside the hbox defined by the insertplot command This is the technique used by CAPTURE to allow T X to manipulate graphics in the same way as text TUGboat Volume 11 1990 No 2 An important requirement however is that the graphics file contain only this relative positioning command start the graphic at the present cur sor location and no other positioning commands The reason is that other positioning commands will either override the relative position command or change the cursor location so that it no longer is coincident with the location of the special com mand As an example the graphic in Figure 2 was inserted using the identical commands as Figure 1 However the file in Figure 2 was not processed to remove the additional positioning commands The result is that TEX still thinks there is an hbox con taining the graphic and even draws a frame around it However the graphics image is offset relative to the special command so the image does not appear inside the frame For this reason CAPTURE contains the FIXPIC utility which is run automati cally after every graphics capture FIXPIC removes all of the positioning control sequences except the relative position command which it may insert if necessary Figure 2 This figure is the same as Figure 3 ez
8. 200 ure environment t e the figure prints by itself on a page separate from the IATRX document Two solutions are always include a prolog along with each Macintosh graphics brute force or include the psglobal inside the first figure environment lucky hacque 4 Conclusion The combination of a Macintosh for producing high quality graphics and IATEX for producing high qual ity typeset documents is becoming very popular as a total document preparation system in many work ing environments The development of tools such as the psfig macros that make integrating Macin tosh graphics in LATEX documents easier will un doubtedly grow in popularity It is hoped that the information collected in this article helps more users produce better documents References 1 Hosek D Report from the DVI Driver Standards Committee TUGboat Vol 10 No 1 p 56 April 1989 2 Varian H and J Sterkin MacDraw Pictures in TEX Documents TUGboat Vol 7 No 1 pp 37 40 March 1986 3 Renfrow J T Methodologies for Preparing and Integrating PostScript Graphics TUGboat Vol 10 No 4 1989 Conference Proceedings pp 607 626 December 1989 4 Woodruff B PostScript and the Macintosh A History MacTech Quarterly Volume 1 Num ber 2 Summer 1989 pp 119 120 5 Encapsulated PostScript Files Specification Ver sion 2 0 Adobe Systems Inc 1585 Charleston Road P O Box 7900 Mountain View CA 94039
9. T X cannot control the position of the graphics The ap plication program must specify the plot location to be the proper position for the TEX document This problem is not entirely intractable Most programs which use absolute position coordinates do so for only the horizontal coordinate The verti cal position is specified only once at the beginning of the file and will be removed by FIXPIC If the desired horizontal position of the graphics can be easily defined centered for example then the ap plication program can generally achieve the proper position The plot will appear at the same location in TEX and will have a vertical position depending on its location in the file We hope to address this problem further in a fu ture release by translating an absolutely positioned file to a relatively positioned one 3 The PK TFM format The logic that graphics should be functionally equivalent to text can be extended by converting a graphic im A age file from the LaserJet PCL lan W guage to the PK and TFM formats which are specific to TeX 8 9 A graphic image in the combined PK TFM format isn t equivalent to a font of type by def inition it zs a font of type For example the graphic at the beginning of this paragraph was generated by converting the graphic seen earlier from the PCL for mat to the PK TFM format using the CONVERT util ity in CAPTURE It was inserted using the same drop macro described earlier and the c
10. TEX The domain of graphics sources for inclusion in PostScript is increased considerably because far more applications support the LaserJet PCL lan guage than support PostScript This idea can be generalized by realizing that the PK TFM format provides a level of device in dependence one of the hallmarks of the T X de sign 3 Once a PK TFM file pair has been cre ated the graphics should be usable on any system that uses the same resolution 300 dots per inch This set includes the LaserJet systems for which CAPTURE was originally targeted screen previewers and PostScript systems We have yet to fully test this idea on other 300 dpi drivers say for the HP DeskJet but the idea is intriguing and has been tested on PostScript drivers 10 This approach also suggests a general design path for future extensions We have argued that separate CAPTURE like programs may be necessary for each computer printer combination However the PK TFM standard provides a level of device in dependence such that a CAPTURE like program may be needed only for each computer resolutzon combi nation TUGboat Volume 11 1990 No 2 3 1 Natural conversions for a TFX graphics system The benefits of a PK TFM conversion utility also suggest other areas where file format conversion may be useful File conversion generally does not offer a new source of graphics because it is somewhat redundant with printer or screen capture How ever converting
11. cs file Spacing between the graphics and the text can then be determined to satisfy aesthetic appeal and is controlled by T X 2 2 Absolute coordinates the exception to TEX positioning Unfortunately some graphics files cannot be pro cessed so as to be relocatable There are appli cations which use absolute positioning commands throughout the graphics file instead of just at the 203 beginning The reason is that absolute positioning commands can considerably reduce the size of the file and the concomitant time to print This issue is important for LaserJet printers without additional memory space Most applications which we have tested do not use this method rather white space is used to position the LaserJet cursor This method requires a larger file and more time to print but the entire image can be moved by changing the position of the cursor at the start of printing When absolute position commands are embed ded throughout the file as opposed to being placed at the beginning only the CAPTUREd file cannot be positioned by TeX The graphics can be captured and included in a T X document but the position will be determined by the application program If an attempt is made to force relocation the image will be distorted because parts of the image will be placed at different locations CAPTURE has an option which enables absolutely positioned graphics to be included in TeX without distortion however
12. er output because OPTEC bypasses both DOS and the BIOS for the printer output However the screen capture utility works fine and there is no loss of resolution Be cause the OPTEC interface uses a common set of device drivers a single raster image is maintained in the program The output to the printer is de rived from the same raster image as the output to the screen the only difference is which device driver is invoked Therefore the screen capture acquires the same image as the printer output An example of an OPTEC II 87 image is shown in Figure 4 The intent of this discussion is to acknowledge that screen capture is a necessary utility for a gen eral graphics capture system Although it is not the best method in most cases there are instances when it is the only method that will work 4 1 Memory management and the terminate and stay resident option The last issue to be considered is the general archi tecture of a graphics capture utility in the MS DOS environment This issue is not applicable to the general TREX graphics problem but is entirely spe cific to the IBM DOS implementation A distinct limitation of DOS is the 640k memory limit which 205 Figure 4 This is a plot of a high numeric aperture wide field of view lens The plot was obtained from the lens design program OPTEC II 87 by SCIOPT _ Enterprises has been a particular nemesis for large complicated programs A premise of the CAPTURE design was
13. from the LaserJet PCL language to the formats of graphical drawing or paint pro grams would be useful The application program would still generate the graphic image saving the user a considerable amount of work but the cap tured graphics could be edited into a final form before inclusion in a document As a test of this idea the CAPTURE CONVERT utility will convert to the PC Paintbrush PCX format 5 4 The case for limited screen capture We maintain that the best method for obtaining graphics is printer capture because of the large source of graphics at high resolution File format conversion generally offers few additional graphics sources and screen capture generally provides low resolution However there are two cases which we have identified in which printer capture is not prac tical Both are apparently quite unusual The first case is an application program which mixes text and graphics in the printer output An example is the scientific program MathCAD by MathSofit Inc Printer capture is not practical with MathCAD because it mixes text characters with the graphics output Although the output can be captured the resulting file cannot be inserted into a TEX docu ment and retain the original likeness The solution in this instance is to use the screen capture util ity CPTS included with CAPTURE CPTS captures the screen image and writes it to a file that can be included in a TEX document 5 Screen capture ef fectivel
14. ilos ophy TeX is considered a document preparation system 2 3 therefore it should have control over all the contents of the typeset page Moreover if graphics are included in a typeset document the graphics and text should be combined in some har monious fashion or the document will be neither aesthetic nor readable It is quite possible to regard a graphics image in TEX as the functional equivalent of a font of type As an example the graphic at the beginning of the preceding paragraph was captured using CAPTURE and inserted using the code segment drop insertplot logo pcl i 1 12 The drop macro is defined in the drop sty file which is available in the public domain 4 It was designed to start a paragraph with a dropped large letter of type as is done with early Bibles and such The drop macro manipulated the graphic image just as it would any other font of type The purpose of this illustration is to demonstrate that a properly processed graphics image can be treated identically to a font of type indeed text and graphics can be indistinguishable for TFX operation An ancillary benefit of this approach is that the artificial distinction between T X and the device driver programs is reduced Perhaps the perception that TEX does not handle graphics well stems from the somewhat artificial separation of TEX from the device driver programs 1 Although graphics must be included on the device driver level the d
15. istinc tion is less severe if T X controls the location and space for the graphics 2 1 File processing and macro definitions TEX will be able to manipulate a graphics element if it is operationally equivalent to a box A box in TEX is a typographic unit which on the most fun damental level is an indivisible character of type 3 Two requirements must be satisfied to establish a graphics image as the equivalent of a TEX box e The space required for the graphics must be de fined as an hbox mbox in IATEX with the same dimensions height and width as the ac tual graphics 201 e The graphics must be positioned inside of the box A box with the proper horizontal and verti cal dimensions can be created with a simple T X macro Once defined it can be manipulated like any other box in TEX A typical definition for the insertplot command used in CAPTURE 5 is def insertplot 1 2 3 vbox to 2 true inf vfill hbox to 3 true in special pcl 1 hfil1 End of vbox 6 6Y End of Definition The insertplot command is functionally equivalent to an hbox in TEX an equivalent form makes an mbox in IATFX It creates a box with the exact height and width of the graphics specified by the 2 and 3 parameters which are obtained from FIXPIC after processing the captured graphics file For example the plot in Figure 1 was created using the following code segment begin figure fhtb begin ce
16. nter fbox kern ipt fbox insertplot surf pcl 1 64 2 13 caption This is output label surf pcl end center end figure GRAVITY DATA CONTOUR INTERVAL 0 76 Figure 1 This is output from the demonstration diskette of the SURFER scientific data plotter by Golden Software Inc A frame has been drawn around the plot to show the box which TFX ma nipulates When the graphics file has been properly processed the box defines the location of the graph ics and the image is surrounded by the frame This macro is essentially the definition for the pfig command contained in the plot sty file 202 which is part of CAPTURE It differs by the use of the fbox command fbox is a IAI X macro which creates a box around the the text parameter and surrounds it with a frame 2 In this instance the insertplot box is substituted for the parameter and a frame is drawn around it The use of the frame command again emphasizes that the insertplot command is functionally identical to an hbox in TeX The fbox command drew a frame around the graphic just as it would around any text block This construct also conveniently highlights the posi tion where TEX thinks the graphics plot is located It is immediately apparent viewing Figure 1 and the macro defined above that the graphics im age is relocatable and has been positioned by T X The insertion macro uses the begin center end center environment to
17. oblem of converting these captured graphics files into a T gX compatible format is com plicated because there are several different LaserJet positioning codes There are 2 codes for specifying either graphics start at the cursor or at the left hand side of the page 6 relative positioning codes rela tive to the old cursor position and 6 code sequences which place the cursor at an absolute location on the printed page All must be removed from the graphics file except the relative positioning com mand code without disturbing any of the graphics data Another problem is the use of additional ver tical white space by some graphics applications White space is simply a series of null data trans fers before or after the graphical image Most of the application programs we tested added some ex tra white space around the image These programs make no assumptions that the images produced might eventually be included in TEX documents so the additional white space may have been included for convenience In some extreme cases white space was used to position the graphics on the page as an alternative to the position commands If it is not removed the additional space will distort the page layout and aesthetic appeal of the document pushing the rest of the text and graphics far from a particular plot In extreme cases it can force a premature page eject Another function of FIXPIC is to remove all leading and trailing white space in a graphi
18. ode sequence 204 font largefont logo drop a The logic that The immediate benefit of this approach may not be clear Operationally there seems to be little dif ference between using the insertplot command and the PK TFM format except that the PK TFM format may be less convenient two files are created instead of one However the advantages of using a PK TFM version of a graphics file accrue from its device independent nature For example none of the commercial TEX page previewers will display graphic images included with the special com mand However graphics in the PK TFM format can be viewed although some previewers we have tested have memory limitations for large images Another benefit is that CAPTURE can be used to supplement the graphics for other systems non LaserJet We have argued that a graphics capture utility is unnecessary for PostScript based systems because the PostScript language describes both text and graphics and the two can be mixed easily How ever the graphics sources are limited because there are relatively few applications on PCs which sup port PostScript due to the high cost and these tend to be concentrated in the desk top publishing area Fortunately many of the PostScript drivers for PC based systems use the same PK TFM font files as the LaserJet drivers 10 Therefore cap tured graphics files which are converted to the PK TFM format can be used with PostScript drivers for
19. that it could be used with large application programs and that both CAPTURE and an application program would occupy memory simultaneously Therefore memory size became an important issue These considerations lead to a design for CAPTURE which minimizes the use of memory while the application program is running For example the postprocessing phase is explicitly removed from the image capture routine the printer and screen capture routines are kept to the minimum size pos sible and as many features as possible are incor porated into the postprocessing program Also the postprocessor is spawned by the image capture rou tines only after the application program has exited Finally CAPTURE does not use a terminate and stay resident TSR design Although a TSR will take no more memory than a normal program a TSR must be explicitly removed from memory before the storage is released If any programs are loaded after the TSR memory can be fractured and the released storage is not contiguous with remaining memory Instead the sequence of operation for CAPTURE runs as follows The image capture routines mod ify the operating system in order to capture graph ics output and then spawn the application program The application program runs and presumably at tempts to output graphics to the printer Once the application program exits CAPTURE loads the post processor program FIXPIC When all processing is complete CAPTURE meticulously ret
20. urns the operat ing system to its original state releases all its mem ory and exits The memory used is a minimum and is never fractured 5 Conclusions We have tried to extend our initial thesis that T X provides an excellent medium for including graphics 206 with text In the case of the PC DOS implemen tation in particular graphics applications are ubiq uitous so there is a wide array of graphics sources Moreover we have suggested a method for includ ing graphics with TEX that allows T X the same control over graphics images as fonts of type This approach affords a seamless blend of graphics and text in the same document The distinction between device driver and TX is softened Although the graphics insertion occurs at the device driver level the control is retained in TpX This idea has been extended to include the no tion of converting graphics files to the PK TFM for mat of TeX The primary benefit of this approach is expanding graphics capture to T X implementa tions which do not use the LaserJet printer In par ticular CAPTURE can support PostScript drivers for TEX that use the same computer modern fonts in the PK TFM format as the LaserJet drivers The range of graphics sources available to PostScript users is considerably increased over the range of applications which presently support PostScript Other exten sions may also be possible We have consistently emphasized that CAPTURE serves as an
21. y converts the text characters into a graphic representation because they are displayed in graph ics mode and can be resolved into individual pixels Moreover there is no loss of resolution The Math CAD printer output is a direct image of the screen display An example of screen capture from Math CAD is shown in Figure 3 Other examples are programs which use instal lable device drivers in the DOS config sys file Fortunately this construct is rare because device drivers for a specific application remain in mem ory attached to the operating system regardless of whether the particular application is being used Valuable memory is wasted and the operating sys tem is cluttered However some applications use TUGboat Volume 11 1990 No 2 276 775 L279 825 Tot Total j i ATNI 8 Ang le 2s j Figure 3 This plot is a screen capture from the program MathCAD by MathSoft Inc The orig inal screen was CAPTUREd converted to the PCX format by CONVERT edited on PC Paintbrush and converted back to the PCL format It was then mod ified by FIXPIC to have a resolution of 150 dots per inch producing a plot with reasonable resolution which fits nicely inside the columns of TUGboat this approach because it provides a uniform interface to all display monitors and hard copy devices An example is the lens design program OPTEC II 87 by SCIOPT Enterprises The CAPTURE printer util ity is unable to capture the print
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