Inserting external figures with GraphicP
Contents
1. METAPOST with all drivers Although META POST generates EPS these text files follow such a simple structure that they can be converted to PDF drawing operators pdfliteral withing TEX as done in ConTRXt s supp pdf tex written by Hans Hagen GraphicP loads this routine in case such an MPS image is to be loaded However these macros consume pretty much TEX memory so they can be disabled by saying usepackage nopdftexmpost graphicp In fact METAPOST output is the only image format that is supported by all drivers of GraphicP It is recognised by an ADSC comment in the EPS header the file name doesn t matter it can be t 1 t eps t ps or anything else METAPOST doesn t emit a high resolution bbox by default but context mp tool mp adds the ap propriate code to extra_endfig Alternatively one can type this into the beginning to the mp file extra_endfig extra_endfig amp special amp ditto amp HiResBoundingBox amp ditto TUGboat Volume 0 2060 No 0 Proceedings of EuroTEX 2003 amp amp decimal xpart llcorner currentpicture amp amp ditto amp amp ditto amp amp decimal ypart llcorner currentpicture amp amp ditto amp amp ditto amp amp decimal xpart urcorner currentpicture amp amp ditto amp amp ditto amp amp decimal ypart urcorner currentpicture amp METAPOST creates EPS files with the wrong extension When reading ajob mp the figur2. a2ping pl below o EPS fixups a2ping p detects and emits all 3 bbox types with proper rounding removes DOS EPSF binary junk removes HP UEL header adds some ADSC comments can read and write from a pipe converts PS to EPS calls sam2p to convert raster images to EPS removes form feed from end of EPS For the PDF EPS direction a2ping pl invokes pdftops a2ping pl can output multipile page PS PDF and HP PCL5 documents with corrected pa per size forced resolution duplex and tumble set tings The ouput of Ghostscript is post processed if necessary a2ping pl can shift images so the lower left cor ner is in the origin but it can also retain the original bbox This works for both EPS and PDF a2ping pl is not only a converter but it contains many fixup routines so it can be used to fix EPS files from a source incompatible with dvips Work pending cropping Now includegraphics always embeds the whole image It should have a clip option just as in graphics sty transformations all 8 combinations of flipping and rotation by 90 should be added imtrix a unified way for replacing labels in EPS and PDF images by those generated by TEX Would be similar to psfrag sty 1007 Szab P ter compatible options includegraphics should have the following options doing the same as in graphics sty bb totalheight keepaspect ratio type ext read viewport optional bbox dots the 1 sp wide white dots that
3. The PostScript printer description should be adist4 ppd 11 Select the following features during installation adist4 ppd print to file optimize for compatibility ADSC PS LanguageLevel 2 embed all the Type 1 vector and TrueType fonts as Typel fonts embed even the standard fonts One may choose between PS DSC or EPS output to avoid rotation Scaling is not im portant because the TFX embedder is able to re scale images Translation can be compensated by 1003 Szab P ter editing the bounding box comment by hand Af ter setting it up any document can be printed from any application to a PostScript file it works sim ilarly as normal printers but a file will be created on disk The bounding box can then be modified by hand and a2ping pl may be applied if necessary If the application can create EPS files by it self it should be compared to the printer driver based generic method Adobe distributes a utility named PDFWriter that can be used from any Windows application to print to a PDF file Using it is not recommended because it completely confuses accented glyphs and even other glyphs in some fonts PostScript has been the traditional page de scription language on UNIX systems for a long time so most UNIX utilities have PostScript output The most important of these are e Acrobat Reader can print to PostScript so it can be used as a PDF to PS converter In the File Print dialog select File and Level
4. are also embedded well The annoying bug of graphics sty of failing to recognise an image pdf as pdf is also eliminated File format decisions implemented in pts_ bbox sty are based on the first four bytes read from the file GraphicP can distinguish between PNG TIFF JPEG MPS EPS created by METAPOST EPS DOS EPSF and PDF properly 1005 Szab P ter External bbox parsing graphics sty can read tiny bbx files that contain only a 4 BoundingBox com ment This is faster and more accurate than full image parsig because bbx files have extremely sim ple syntax GraphicP accepts graphicPmeta com mands instead of bbx files Each of these com mands describes a single image file for example graphicPmeta i 1 EPS MPS 0 0 99 534 graphicPmeta i 2 EPS MPS 8 9 10 76 A list of these lines can be inserted right into the tex document before typesetting the images or it can be input from a separate file proposed exten sion gpm A Perl script called img bbox pl is included in GraphicP to generate these lines For example use the command img_bbox pl tex eps pdf jpg tiff png gt all gpm The script supports more than 42 image formats included all formats embeddable by graphicp sty File names may contain TEX control characters they are properly escaped Getting the bbox of a PDF the MediaBox is rather complicated because it is deeply hidden somewhere in page tree of the binary PDF file Ne
5. drivers in a more compati ble way than the traditional 4 TEX embedder graph ics sty GraphicP also contains many converters that fill the gap between the various output file formats of the powerful image editors and the formats the printer drivers work well with The converters do not enhance the visual appearance of the image but they ensure that bounding box and orientation in formation is emitted properly and they also do some syntactical changes They try to work smarty with out image specific instructions from the caller Existing printer drivers are fairly good pro vided that the embedder gives them specific and correct instructions what to do However existing WYSIWYG image editors cannot cooperate with TeX well Their output has often to be adjusted by hand or using specific converters 1008 The aim of graphicp sty is not to compete with or replace graphics sty but to provide a proof of concept alternative showing that some of its func tionality can be implemented better The key un matched benefits of graphics sty are the framework approach support for many printer drivers and the time it has been tested Extending graphics sty with the features of GraphicP while retaining these bene fits would be a glorious but enormous work The scripts and other programs of GraphicP are as far as its author knows unique They can be used together with both graphics sty and graphicx sty and even for generic image pr
6. forcibly mark the bounding box of the image should be made optional arithmetics more complicated arithmentic expres sions than width 0 9textwidth should be al lowed in width and similar options testing with images originating from various pro grams Conclusion The most important benefit of TEX is that it helps authors and typesetters to produce beautiful printed documents Although inserting figures to TEX doc uments isn t easy TEX help us to make the images consistent and pretty There are serious quirks and limitations during production conversion and inclu sion but once the image has been included properly it remains there without accident it won t overlap the bottom margin unless explicitly requested it will be numbered and floated properly it will never be torn from its caption etc The total size of the images doesn t affect TEX it runs happily albeit slowly on a book with thousands of large images and never crashes Beyond creativity the authors must have the technical knowledge to create docu ments with images but they can also enjoy many benefits unique in computer typography The author uses several tools when dealing with images image editors converters the embedder and the printer driver It is essential that these tools work properly and they can communicate with each other GraphicP provides an embedder implemented from scratch that gives more flexibility to the author and instructs the printer
7. is that introduces errors larger than the minimum 2717 pt For example 0 00001 in 0 0011 pt but 0 0000 05 in 0 0 pt The TEX primitives are not suitable for scaling because multiplication is not accurate enough it re sults in overflow and there is no built in real num ber division at all So a high precision unoverflow able scaling operation has been implemented from scratch in divl6b sty Its internal number represen tation is 30 32 signed fixed point and it stores a number in two TEX count registers Input and out put values are still 15 16 real numbers Due to the increased precision overflow can never occur and TUGboat Volume 0 2060 No 0 Proceedings of EuroTEX 2003 Inserting external figures with GraphicP the multiplication is always accurate even 1 sp 1sp isn t truncated The division routine does repeated subtraction possibly doubling or halving the divi sor after each subtraction Halving may introduce small internal rounding errors but fortunately no error occurs when the scaling ratio is a 2 where a and b are integers Empirically the error of the scaling algorithm in practical image sizes 100 3000 pt is 0 2sp while the result of Gscale div in graphics sty devi ates sometimes as much as 1 pt which is noticable Another drawback of graphics sty is that it calculates different widths inside normal latex and pdflatex Enforced dimensions When the user specifies width or height
8. s already EPS and the PDF specific drivers in GraphicP can embed it to a PDF document without external converters It is possible to embed TEX output into TEX the PDF files created by pdf tex can be included directly and the PostScript out put should be run through a2ping pl to create EPS Sometimes a multi step conversion produces the best results For example the author of this article often uses the pipeline of PostScript printer driver Acrobat Distiller Acrobat cropping and EPS out put Acrobat Distiller pdftops to create a small and portable EPS file that can be embedded Content management Additional information has to be remembered for each image proposed im age title caption which documents or floating fig ures contain the image the file name the editable source file of the image how it was converted from its source is it available in another format e g both EPS and PDF the label the figure will have etc Keeping this meta information up to date is im portant if either the images or the document con taining them are planned to be reused in the far future The author of the document should decide how to face this orgaziation task Only some hints are provided here On UNIX systems it is traditional to write a Makefile for compilation even document compila tion The enough _tex pl is provided in the GraphicP distribution for convenience it runs TEX enough number of times to resolve all references and in
9. 2 Only uncheck Fit to Page and Download Far East fonts check Download Fonts Once and Use Printer s Halftone Screen As an alternative invoke acroread toPost Script level2 e Ghostscript can convert PostScript to PDF The epstopdf utility by Thomas Esser makes this easier but a2ping pl is a better replacement from the command line e dvips E creates EPS files but it sometimes computes the bounding box wrong so a combi nation of dvips and a2ping pl is necessary e Figures created by XFig can be converted to EPS with acommand fig2dev L eps in fig gt out eps Also XFig can create EPS files and newer versions can even make TEX typeset some of the labels The Special Flag should be set to Special in the Text Edit panel and the file exported as Combined PS IATEX with name out eps Then input out eps_t should be called Unfortunately it is impossible to post scale the image this way e Both Netscape Navigator and Mozilla can print to PostScript but their output is rather ugly The printed output of Internet Explorer is not so ugly but tables are often cropped at right e The GIMP can print to both PostScript and EPS but sam2p is usually a better solution e pdftops from xpdf can convert PDF to PS and EPS Unfortunately it doesn t work with weird fonts or encodings well and older versions sim ply discard PK fonts embedded by pdftex 1004 The output of METAPOST doesn t need conver sion because it
10. Inserting external figures with GraphicP Szab P ter Budapest University of Technology and Ecomomics Department of Analysis Mtiegyetem rakpart 3 9 Budapest Hungary H 1111 pts eurotex math bme hu http www inf bme hu pts Abstract This paper describes GraphicP a new unified IATEX and plain TEX package that provides a fast and reliable method for including external images into TEX docu ments The includegraphics macro of GraphicP is a drop in replacement of the same command of IATRX graphics sty and graphicx sty but with many enhance ments Drivers for xdvi dvips pdftex and dvipdfm are included Useful tips are given for converting vector and bitmap images into a format usable for inclusion typically EPS or single page PDF Overview of image inclusion There are many different technologies to embed ex ternal images such as photos figures function plots and diagrams into TEX documents Most methods involve the following steps 1 designing drawing the image in an external program 2 converting it to a file format recognised by TEX 3 loading an embedder a TEX package that can embed images 4 placing inclusion commands at places of the tex document where the image should appear There are additional less common steps 5 providing feedback to the image drawing pro gram about the final image size and position 6 replacing fonts and glyph sizes in the image to match the main text font compensa
11. LanguageLevel 2 or 3 not supported by old printers low compatibility some programs emit 100kB of procedure sets that are not used anyway or they represent object inefficiently big size Thus it is worth knowing more than one way to do the same file format conversion Unfortunately there is no golden rule the best EPS and PDF output can be found only by experimenting If the original image is in raster format the sam2p command line utility should be used to cre ate a small and compatible PDF or EPS file sam2p with the help of tif22pnm png22pnm and djpeg can read today s most popular raster image formats The author should save the image in an intermedi ate format recommended PNG or TGA and feed that to sam2p The first page of a normal PostScript document can be converted to an EPS or PDF with a2ping pl part of GraphicP for example a2ping pl in ps out eps For the PS PDF conversion a2ping pl calls Ghostscript with the device pdfwrite Ghost script 7 00 or more recent is recommended to avoid missing objects and low quality glyphs The PDF output is quite small As an alternative Acrobat Distiller can be used for converting PS to PDF but it is not free and the settings should be specified properly to create a small and compatible PDF There is a general EPS export method for any Windows and Macintosh application that is able to print It needs the PostScript printer driver freely available from Adobe 10
12. and During development and testing I have been using plain TEX because porting it to TEX is almost trivial compared to the other direction More accurate calculations Knuth has designed TEX not to use floating point numbers This is an important portability advantage because the differ ent rounding implementations of the CPUs don t af fect the positions of line and page breaks calculated by TeX It would be a painful headache for exam ple if the same TEX document compiled differently on the author s Linux system and the publisher s Solaris system Real numbers in TEX are represented in 15 16 signed fixed point notation That is 15 bits are re served for the integer part and the sign and the precision is 2716 so a rounding up to 271 pt may occur after each operation Fixed point arithmetics has the important advantage that additions and sub stractions are always accurate But what about multiplication and division When scaling an image of size wd x ht to the de sired width dwd the actual height is calculated as ht dwd wd Multiplication and division are equally important operations of image scaling and often the result of the multiplication exceeds the maximum TEX dimension of about 16000 pt TEX provides real number multiplication with the following trick dimen0 42pt dimen1 0 333333333 dimen0 showthe dimen1 The calculated result 13 99979pt is not accurate Another weakness of the built in multiplication
13. aper describes steps 2 4 in detail us ing tools traditional for years including Ghostscript dvips dvipdfm pdftex METAPOST the convert util ity of ImageMagick The GIMP as well as replace ment tools from the new GraphicP package avail able from CTAN The a2ping pl utility replaces ep stopdf and others img_bbox pl replaces ebb from dvipdfm pdfboxes pl improves PDF files graphicp sty replaces traditional TEX graphics sty and plain TEX epsf tex These new tools work together with the sam2p 1 raster image converter which replaces tiff 2ps and the EPS and PDF export filters of other image processing software such as convert This pa per compares the new and the replacement tools TUGboat Volume 0 2060 No 0 Proceedings of EuroTEX 2003 1001 Szab P ter in detail and proposes a more reliable and accu rate general image embedding technology for both BTEX and plain TEX using the proper combination of these programs The embedder TEX doesn t understand image files In particular T X cannot extract an individ ual pixel line or label from an image The only reason why the embedder macros running in TEX read the image file that they need the bounding box for proper scaling The bounding box or bbos is a rectangular area of the image file that con tains all visible parts of it The bbox is of the form IIx lly urx ury in which the point at Ix Ily is the lower left corner of the image and the p
14. cP intends to be a stable and accurate replacement for graphics sty fixing many problems but without changing the syntax of the include graphics command substantially It doesn t con tain fundamental additions only small fixes and ad ditions and increased consistency and portability As GraphicP evolved it has been extended with Perl scripts for example a2ping pl and other stan dalone programs in addition to the TEX macros in graphicp sty These external programs are optional because a UNIX system is needed by some of them graphics sty implements a framework separat ing the general high level functionality from the prin ter driver specific low level one For example the command usepackage pdftex graphicx loads the graphicx sty user interface with the pdftex def driver The other interface graphics sty differs in the syntax of the includegraphics command This separation is a good design choice in gen eral but it makes more difficult to do fundamental changes Another drawback of graphics sty is that it TUGboat Volume 0 2060 No 0 Proceedings of EuroTEX 2003 is tightly integrated into ATRX so it would be quite difficult to add plain TEX compatibility GraphicP has been implemented from scractch The name of its embedder pgraphicp sty suggests that it can be used as a replacement of graphics sty For example the ATEX example of Footown above works by re placing the first line with usepackage dvips g
15. dices It can be inserted into a Makefile instead of bare latex invocations Makefiles may also automate image conversion creating EPS and or PDF from the source images before compiling the document It is wise to retain an EPS PDF PNG or JPEG copy of each image so they can be opened decades later because tools that can open these formats with the same schemantics as today are expected to be available for a long time In the contrary propri etary and closed file formats should only be used for temporary storage if the company won t support the file format any longer it will be impossible to open such images later The same is true for TEX texts one should make a backup of all classes styles and auxilary macros files including those that were used to create the format file plus all source and image files belong ing to the specific document A full backup elimi nates the risk that a tex source doesn t compile anymore or it compiles with different line breaks The Linux strace utility can list all files opened by latex and other programs TUGboat Volume 0 2060 No 0 Proceedings of EuroTEX 2003 Features of GraphicP Runs on both plain TFX and FTRFX It con tains a compatibility layer laemu sty in plain TEX that provides the ATEX package loading error and warning indication and some other simple common macros Care has been taken to use plain TEX con structs whenever possible e g def instead of new comm
16. e under the scope of beginfig 42 will have the file named ajob 42 Passing a negative number of beginfig will create ajob ps These settings are hard wired into METAPOST thus the files have to be renamed before inclusion with graphics sty GraphicP doesn t have this limitation Better Babel compatibility Many Babel lan guages make the characters and active This con flicts with the METAPOST loader and other PDF specific code graphics sty borrows from ConTRXt so usepackage pdftex graphicx usepackage magyar babel is the correct loading order Users of GraphicP don t have to care because it uses external code only for METAPOST EPS to PDF conversion wrapped by proper catcode resets so no error occurs Backward compatibility Although the TeX and IATRX interfaces used hasn t changed much in the last few years pdftex is under development Gra phicP adjusts itself to the version of pdftex running it GraphicP has been tested with pdftex 0 12r De bian Slink 0 14 and 1 00a Debian Woody graphics sty is not UNIX specifix it should work in any architecture or OS TeX has been ported to but the Perl scripts provided in the GraphicP dis tribution require a UNIX system currently They can be ported to other platforms easily if there is considerable interest For educational purposes graphicp sty provides includegraphicP and graphicx sty provides inc ludegraphics can be loaded in this order Draft su
17. fTeX dvipdfm 6 compatiblity with other printer drivers ot 7 reuse of the same image object if embedded multiple times 8 running text around the image 9 support for floating figures 1002 Requirement 9 has been well supported for a long time in E4TEX by the table and figure en vironments However requirement 8 is solved only with limitations in floatflt sty The other require ments are correlated more strongly they are imple mented in the de facto standard for an embedder of ATEX graphics sty includes both graphics sty and graphicx sty It is well documented and it provides a convenient syntax and unified printer driver and file format independent interface for in cluding any kind of rectangular image into ATEX documents Using it is rather easy usepackage dvips graphicx begin document begin figure includegraphics width 0 9 textwidth footown eps caption The map of Footown end figure end document graphics sty is not available for plain TEX but there is a similar but less powerful package specific to EPS images epsf tex An example input epsf in plain TeX epsfxsize 0 9 hsize epsfbox footown eps Why GraphicP graphics sty contains several in consistencies and weaknesses which document au thors must care of when embedding images Some of these problems are just annoying quirks others af fect the image placement and scaling visible to the reader Graphi
18. i ther GraphicP nor graphics sty can do this reliably when running inside tex both of them expect the MediaBox to be in a line on its own and they can be confused when there are multiple such lines The solution is to run GraphicP inside pdftex or to get all four bbox coordinates to use img_ bbox pl which can navigate the PDF page tree properly As an alternative GraphicP contains another Perl script pdfboxes pl which modifies an existing PDF file so that the bounding box will be available right in the beginning This is essentially a proof of concept implementation it proves that it is possible to insert a new object into a PDF file and modify all offset references to other objects without the need to parse and regenerated the full PDF sam2p 0 43 and above emits the bounding box early enough so pdfboxes pl is not needed a2ping p can detect all 3 bounding box types the setpagedevice and other PostScript operators Internal bbox parsing The bbox extraction ca pability of graphicp sty is limited by the fact that TeX reads files line by line thus it is hardly pos sible to parse a binary file properly catcodes are used extensively to ignore most of the binary junk so the dimensions of PNG TIFF and JPEG files cannot be extracted and PDF parsing is very lim ited Fortunately pdftex provides primitives to ex tract the bounding boxes of these binary files and dvips doesn t support these file formats anywa
19. ndows users working with a word pro cessor haven t heard of PostScript and have never used PDF for embedding The Windows clipboard and OLE hides the file format as long as the im age can be copy pasted its format doesn t matter This user friendly approach is not available in TEX beacause it is technically impossible to copy paste binary image data into the human readable tex source Thus each image has to be saved into a separate file and the tex file contains only refer ences to these files in the form of includegraphics commands The file format depends on the printer driver it should be in general EPS for TEX com bined with dvips and PDF for pdftex and dvipdfm TUGboat Volume 0 2060 No 0 Proceedings of EuroTEX 2003 Inserting external figures with GraphicP Conversion to EPS or PDF EPS and PDF files are not editable easily so they should be converted or exported by the preferred image drawing appli action of the author Most modern vector graphics editing programs including Illustratpr CorelDRAW Visio Acrobat InDesign and QuarkXPress have direct EPS export feature some of them can export PDF One has to consider the quality the compati bility and the size of the exported image Some pro grams build up circles using a constant number of straight lines or cannot emit glyphs in vector format low quality some images contain proprietary or legacy junk or they need new features of PostScript
20. ocessing purposes unre lated to TEX GraphicP is hoped to increase the efficiency of everyday image processing tasks done by TEX authors and publishers References 1 Szab P ter Inserting figures into TX docu ments In proceedings to EuroBachoTex 2003 2 Han Th Thanh Sebastian Rahtz and Hans Hangen The pdfTRX user manual teTRX doc pdftex base pdftexman pdf gz 1999 3 Mark A Wicks Dvipdfm User s Manual te TX doc programs dvipdfm dvi gz 1999 4 Tomas Rokicki Dvips A DVI to PostScript Translator teTEX doc programs dvips dvi gz 1997 5 D P Carlisle Packages in the graphics bundle teTEX doc programs grfguide ps gz 1999 6 Keith Reckdahl Using Imported Graphics in FATEX 2 teTkX doc programs epslatex ps gz 1997 7 Adobe Developer Support PostScript Lan guage Document Structuring Conventions Spec ification Version 8 0 Adobe Developer Tech nologies 1992 8 Ed Taft Steve Chernicoff and Carline Rose PostScript Language Reference Addison Wesley 1999 9 Jim Meehan Ed Taft Steve Chernicoff and Carline Rose PDF Reference Second edition Addison Wesley 2000 10 http www adobe com support downloads main html select PostScript printer drivers 11 PPD for a generic printer http www unipr int ee Web OpenResource aspx ResFile 47 and http www rgraphics com downloads ADIST4 PPD TUGboat Volume 0 2060 No 0 Proceedings of EuroTEX 2003
21. oint at urx ury is the upper right corner It is a common tradition to have lx 0 lly 0 urx image width ury image height Once the bounding box has been extracted and the de sired width of the included image is known the embedder can calculate the actual height and leave empty place for the image on the paper The embedder inserts the image file name the computed horizontal and vertical scale factors into the DVI file as a special The printer driver is responsible for loading the image file and send ing it to the printer properly scaled and rotated The image file format must be compatible with the printer driver For example the popular printer driver dvips requires all images to be in the En capsulated PostScript EPS format pdftex accepts PDF PNG JPEG and TIFF images dvipdfm ac cepts PDF PNG JPEG and METAPOST EPS im ages Usually the author of the image prefers a dif ferent file format for development so conversion is necessary Some converters are safe efficient and faithful in the sense that they create valid and small output without information loss but others have to be used with great care The most important requirements of an embed der are 1 ability to specify the image size and or scaling 2 ability to specify rotation angle and mirroring 3 ability to clip unnecessary parts crop 4 extracting the bounding box properly from all file formats full compatibility with dvips pd
22. pport It is often desirable to omit im ages from the document especially in the develop ment phase where fast compile redisplay cycles are of primary importance Of course the place of the images still has to be reserved Contrary to graph ics sty GraphicP supports this kind of draft mode by specifying the appropriate driver e g usepackage driver invisible graphicp The supported draft drivers are invisible a transparent rectangle is displayed with out the image TUGboat Volume 0 2060 No 0 Proceedings of EuroTEX 2003 Inserting external figures with GraphicP blackbox a solid black box is displayed showing the bounding box wastes a lot of ink frame a black rectangular frame shows the bound ing box namedframe the image file name is displayed in the black rectangular frame Uses textan in asciiall sty if available to display weird charac ters in file names The real drivers are pdftex the default driver when pdfT Xis detected Cannot display EPS images dvi a common subset of dvips and dvipdfm This is the default when running under normal non pdf TEX Can display EPS and MPS only dvips cannot display PDF and raster images dvipdfm calls Ghostscript to convert EPS to PDF automatically The file texmf dvipdfm config should be up dated to improve bounding box calculation and oth ers during EPS to PDF conversion don t forget to enter the actual path to a2ping pl D zcat f Zi
23. raphicp Preparing the image for inclusion PostScript is a two dimensional page description lan guage that can fully describe the visual appearance of printed material A PostScript document is com posed of straight lines curves filled regions delim ited by these text bitmap images and others PDF is a portable document format mainly for distribut ing two dimensional mainly static material in elec tronic form The graphics model of PostScript and PDF is the same so in the ideal case there is no loss of information or precision when converting between PostScript and PDF Other important differences such as sheet trim ming colors slide shows and web hyperlinking are not considered in this document Any image bitmap vector and combined can be faithfully represented in PostScript and PDF The EPS Encapsulated PostScript file format is a single page PostScript with some other minor re strictions so it is perfectly suitable for represent ing inline images in a document There is no re striction in PDF any one page PDF can be treated as an image Most TEX printer drivers accept the images in either EPS or PDF so the goal of this section is to convert any image to both of these formats Note that TFX and dvips cannot embed normal PostScript documents because the bbox is missing and PostScript documents may contain de vice dependent or global state changing operators Use a2ping pl to convert PS to EPS Most Wi
24. te the effect of scaling and to allow TEX math formulas 7 replacing line widths to compensate scaling In some technologies these steps are integrated so the non WYSIWYG image code can be typed directly into the tex document Examples are the IATEX portable picture environment and its variants epic eepic gastex Xy pic MFpic ConTRXt s inline METAPOST environment This paper discusses only the generic process of embedding external images not these integrated specific solutions In WYSIWYG word processors images are usu ally inserted by opening them in their appropriate appliaction and using the clipboard to copy them to the document inside the word processor Scale ro tate move and resize operations are performed with the mouse providing instant feedback to the author about the final appearance of the image and how it affects text flowing around it Compared to this the steps above seem to be overcomplicated and a real pain to the author This is partly because easy handling of images needs a WYSIWYG environment with instant feedback while editing TEX by de sign lacks both of them So inserting images to TEX documents is expected to be a tedious process no matter how sophisticated tools are used Never theless it is worth improving the tools so TEX can compete with other document preparation methods Emphasis should be put on quality stability com patiblity and output size not on ease of use This p
25. these will be enforced us ing hss irrespective of what the driver generates graphics sty doesn t have this feature and consider ing the less accurate image scaling the differences up to a few pt can occur and this can seriously effect further line and page breaks in the document Gives bbox hints It is possible to convert a TEX page to EPS with dvips E dvips calculates the bounding box of the page automatically taking into account the glyphs and rules on the page Unfortu nately version 5 86e still detects the image bounding box wrong especially with images descending below the baseline GraphicP works around the problem by forcing dvips exclude the image from the calcu lation and adds two small invisible white rules at the corners This feature can be disabled A similar problem occurs in xdvi which some times crops too much from the edges of the image It is solved by forcing it not to crop at all Cropping can be controlled from special PSfile but printer drivers interpret it differently so the spec ification emitted by graphicp sty disables cropping completely This also solves a similar problem with dvipdfm which would otherwise crop EPS images below the baseline File format detection As opposed to graphics sty GraphicP doesn t rely on the the file name to determine the file format Files with bogus or in valid extensions are treated properly and EPS files created by METAPOST img 1 img 2 etc
26. y 1006 All 3 types of EPS bounding boxes are sup ported the user can choose between the exact and the rounded bbox if both of them are present The default is to choose Exact then Hires then nor mal rounded to integer bounding box This can be overridden by hiresbb and exactbb Nonzero depth Images can be lowered below the baseline for example includegraphics lower 20 t eps moves the image down by 20 bp Also Gra phicP can recognise negative lower left in the bbox and move the image below the baseline automati cally only with below Horizontal movement is not possible but the user can insert the appropriate kern commands before and after the image Raster images are always aligned onto the base line so an explicit lower or raise should be used instead of below to move them vertically Alternatively sam2p has the m lower dimen op tion that creates a pre lowered EPS or PDF from the raster image a2ping pl automatically raises images up to the baseline unless the below option is given Avoids duplication dvipdfm and newer versions of pdftex both support Form XObjects a means for reusing material already typeset GraphicP uses From XObjects to embed an image file only once no matter how many times it appears in the docu ment This optimization is impossible in PostScript documents because they are read sequentially and caching images already read imposes a high risk of memory shortage
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