KEYNOTE ADDRESS: Portable Graphics in TEX
Contents
1. TUGboat 7 3 pages 171 175 1986 Gehani N Tutorial UNIx Document Formatting and Typesetting IEEE Software pages 15 24 September 1986 Gruber H E Krautz H P Fritzer K Gatterer G Sperka W Sitte and A Popitsch Electrical Resistivity Magnetic Susceptibility and Infrared Spectra of Superconducting RBagCu307 with R Y Sc Tm Ho Eu Nd Gd Pages 83 88 in High T Superconductors H W Weber ed New York Plenum Press 1989 Heinz Alois Including Pictures in TEX Pages 141 151 in T X Applications Uses Methods Malcolm Clark ed Chichester England Ellis Horwood Publishers 1990 Hoenig Alan Fractal Images with TEX TUGboat 10 4 pages 491 498 1989 Kernighan Brian W pic A Language for Typesetting Graphics Software Practice and Experience 12 1 pages 1 21 1982 Kernighan Brian W The UNrIx Document Preparation Tools A Retrospective Pages 12 25 in PROTEXT I J J H Miller ed Dublin Boole Press 1984 TUGboat Volume 13 1992 No 3 Proceedings of the 1992 Annual Meeting 259 Malcolm Clark Knuth Donald E The TRXbook Reading Mass Addison Wesley 1984 Knuth Donald E The METAFONT Book Reading Mass Addison Wesley 1984 Knuth Donald E Fonts for Digital Halftones TUGboat 8 2 pages 135 160 1987 Lamport Leslie ATEX A Document Preparation System Reading Mass Addison Wesley 1985 Maus Doug and Bruce Bake2. open ness and the portability of documents created with TEX It will have become apparent that we are always in the hands of the drivers available This is perhaps the weakest link in the whole chain Whether you regard the drivers as part of TEX or not depends on your viewpoint KEYNOTE ADDRESS Portable Graphics in TEX It is perhaps wise to remind ourselves that even in the days of Johann Gensfleisch zum Gutenberg the integration of text and illustration through woodblocks took some time and could only be achieved after agreement with the professional woodblock cutters Bibliography Andrews Phil Integration of TEX and graphics at the Pittsburgh Supercomputing Center TUGboat 10 2 pages 177 178 1989 ArborText Dvilaser PS User Manual 1989 Beebe Nelson H F A TEX DVI Driver Family TEXniques 5 pages 71 113 1988 Beebe Nelson H F TEX and Graphics The State of the Problem Cahiers GUTenberg 2 pages 13 53 1989 Bruin Rob de Cornelis G van der Laan Jan R Luyten and Herman F Vogt Publiceren met LTEX CWI Syllabus 19 1989 Clark Adrian F Halftone Output from TRX TUGboat 8 3 pages 270 274 1987 Clark Adrian F Practical Halftoning with TEX TUGboat 12 1 pages 157 165 1991 Darrell Trevor Incorporating PostScript and Macintosh Figures in TEX Electronic document available with psfig commands 1987 Ehrbar Hans Statistical Graphics with TEX
3. of other arbitrary plotting languages could be mapped onto the Metaplot commands which were then shipped to METAFONT CGM or Computer Graphics Metafile is worth considering too It has a couple of features which we ought to bear in mind It is an international standard Nominally every graphics package ought to have the facility to generate CGM and also to read it in The metafile should also be able to be transmitted over electronic networks with the minimum of fuss The other feature is that CALS Computer aided Acquisition and Logistics System has adopted CGM as one of its components while we may worry about the militaristic background of CALS it has done much to revitalize and make acceptable SGML and we can expect it to help in the adoption of CGM One other component of CALS is that it has adopted another graphics standard IGES IGES is usually described as a de facto standard it was developed principally for use with CAD CAM software Nevertheless it does offer another routeway In essence there is no real reason why Metaplot could not read an IGES file and transform it to METAFONT form Since we are in the real world of standards Heinz 1990 notes that GKS Graphics Kernel Standard may also be transformed into TREX Another route to create a character If we look a little more closely at what a driver actually requires to set a character we note that there are two items the pixel file and the TEX font
4. do not include CGM files in specials In fact this has been done Andrews 1989 Provided the driver can handle the commands and change them into the correct form for the output device any sort of file can be processed As noted earlier the dvi is itself a sort of metafile Andrews extensions work for UNIX and VMS environments PostScript is not yet ubiquitous Fortunately there is also an approach which allows us to use a Hewlett Packard LaserJet CAPTURE Pickrell 1990 Any program which produces output for a LaserJet can have that output processed with CAPTURE to produce a file which may be input to TEX through some suitable commands which will somewhere employ specials Again this sounds longwinded but there are a great many programs which will do this Even more remarkable there are programs which can take PostScript and turn it into LaserJet form Freedom of the Press GoScript Ghostscript etc This means that we are now relatively independent of PostScript In Betweens A few years ago the notion of little languages became current This is a scheme which is found most generally in UNIX Instead of adding features to troff little languages were created pre processors which massaged some reasonable form of input into troff These include chem for chemistry tbl for tables eqn for equations grap for general graphs and pic for pictures The one we are interested in is pic and perhaps
5. is why it has been mentioned here And lastly the one that really does pictures Rolf Olejniczak s texpic 1989 This is a T X implementation of pic which does all the things that pic does and more and works in just the way outlined What is the snag The driver has to be implemented on all sorts of different machines We are gnawing away at the portability Including Post Script or Hewlett Packard s laser printer language seems also eminently non portable At least this localizes the problem and in the longer term gives a far more general solution Olejniczak s program is available only for MS DOS and is currently proprietary although it is not especially expensive It is the restricted platform which is the real problem Closing Comments Beebe 1989 Rahtz 1989 and Heinz 1990 have all contributed to the discussion of incorporating graphics into TEX documents The adoption of the METAFONT and pk tfm solution goes some way to ensuring the transportability of documents None of the other approaches yet comes close enough to being capable of being transmitted over fairly arbitrary networks Another advantage of this approach should be the capability of viewing the diagrams on the screen as well as on paper The tools which enable these transformations ought to be part of the standard TEX distributions Within a closed environment any solution which works is to be applauded But one of the major features of TEX is its
6. In this way we have a single document and the opportunity to revise An advantage of course is that everything is in IA TEX so that we can ensure that the relative weights of lines the font sizes the symbols blend in well with the rest of the document This is a feature which we should not ignore A further advantage is the ability to preview the diagram on the screen Since the METAFONT descriptions of the fonts are available the screen fonts may also be generated The use of the rules might indicate that you could build the most complex curves out of small rectangular boxes make them small enough and it will not be possible to see the join In fact an extension to IATRX picture environment is the bezier style which allows a b zier curve to be plotted see Figure 5 Make too many of them and TEX runs out of memory TUGboat Volume 13 1992 No 3 Proceedings of the 1992 Annual Meeting KEYNOTE ADDRESS Portable Graphics in TEX After rotation about the focus F by 15 The parabola y 27 4 before rotation Figure 6 from Wichura 1987 PCIEX graphics Resolution becomes an issue if we try to create continuous curves from small elements If TEX memory fills up quickly at 300 dpi it will fill up even more quickly at 1270 dpi It is difficult to claim device independence when we must take resolution into account We can of course ignore the resolution problem but on those times when we want to pro duce h
7. KEYNOTE ADDRESS Portable Graphics in TEX Malcolm Clark Information Resource Services Polytechnic of Central London 115 New Cavendish Street London W1M 8JS England Phone 44 71 269 3555 x3567 Internet malcolmc mole pcl ac uk To a very large extent TEX was designed for the placement of characters on a page It was implicitly assumed that the characters were probably alphabetic or mathematical Nevertheless Knuth notes If you enjoy fooling around making pictures instead of typesetting ordinary text TRX will be a source of endless frustration amusement for you because almost anything is possible While it is well able to draw horizontal and vertical lines or even to plot dots more or less at random see for example Knuth 1986 p 389 and Figure 1 most people expect a little more from their graphics There is also an architectural limitation although TeX could easily simulate an arbitrary continuous curve by placing a very large number of small dots or rules on the page or screen TEX was only granted a finite memory You quickly run out of memory This is all the more distressing since there now exist versions of TREX with small and large amounts of memory basically related to the addressing ability 64 bit TEX on a Cray has potentially much more memory than 16 bit TEX on a pe TRX in UNIX is generally somewhere in between Sadly this has had the effect of making TEX documents less portable and serious
8. cific boxes UNIX may be the de facto operating system just as PostScript is the de facto page description language But there are more non UNIX boxes out in the world than there TUGboat Volume 13 1992 No 3 Proceedings of the 1992 Annual Meeting 253 Malcolm Clark are UNIX boxes Similarly there are more non PostScript output devices than there are PostScript outputs If everybody were to standardize on the same computing box many problems of interchange would go away but this is unlikely to happen Special Fonts This first approach is limited but very general it will work with TeX and any of its drivers It is possible to use special fonts to build pictures Again there are three main ways to do this the first is through simple font elements that is straight line segments or curves which can be assembled to give fairly simple pictures The second is through METAFONT Here we use METAFONT to create a single character which is our graph or whatever This seems intimidating but need not be And lastly we can create special fonts without METAFONT Simple font elements So start with the simple font elements Knuth gives an example in The TEXbook pages 389 391 but the font he uses is not generally available Alternatively IATEX already does this in its picture environment cf Lamport 1986 pp 101 111 Unfortunately Lamport did not develop this to the same extent as the rest of LATEX and it has a di
9. e imagine we want to ship out a couple of PostScript commands represented by lt command gt Using Teztures on the Macintosh which has its own built in driver you could say special postscript lt command gt Using ArborText s 1987 PostScript driver Dv LASER PS the command is specialfps lt command gt Using the public domain DvI2Ps the structure is special pstext lt command gt or using another public domain driver Dvips Tom Rokicki the equivalent is specialps lt command gt or specialps lt command gt while Nelson Beebe s driver Beebe 1987 appears to have no way of including a single command you could obviously use the facility to read in a file which itself contained only one command similarly Personal T X s PostScript driver Personal TeX 1987 appears to lack the in line command feature Trevor Darrell 1987 wrote a useful set of commands psfig which greatly ease the prob lems of incorporating PostScript into a document The PostScript is really encapsulated since the bounding box information is required Encapsu lated also implies that the PostScript should not change the state of commands in other words that any changes should be local in TeX termi nology The portion of psfig which deals with the specials is well separated and it is possi ble to modify that part of the command suite for particular drivers You could reasonably ask why we
10. g Gem Draw Chemical structure Page makeup editor e g ChemDraw e g Ventura via PDL e g PostScript Figure 2 Using the IATRX fonts from Norris and Oakley 1990 Computing Costs Q 10 20 30 40 50 60 70 80 90 100 Jan compute other Key z Feb EE disc space Mar MS geoid E Apr May E Super 88 oo Chapman Conf Figure 3 Bar chart from Nagy 1989 Figure 4 Simple chemistry with LATEX fonts from de Bruin et al 1988 Because of this generality there are some pre 254 TUGboat Volume 13 1992 No 3 Proceedings of the 1992 Annual Meeting Figure 5 B zier curves and control points from Beebe 1989 processor programs which will allow you to create something interactively which is then transformed into LXTEX commands If you have access to a UNIX system gnutex can assist On an MS DOS system part of the emTRX package does just this although it adds a few extra features of its own The key drawbacks of the LATEX special font approach are centered around the limited fonts which are available both in the slope of lines and their thicknesses and the limited range of curves These very limited resources can be encouraged to generate quite an amazing range of possibilities But an enormous amount of time and effort is also required Having said this traditionally a tremendous amount of effort had to be expended to create diagrams like these anyway
11. grap pic has a language which allows creation of line diagrams with embedded text Sounds simple Of course with the way that UNIX works it is easy to write a command line which hides all the little language bits and pieces from the end user How is this relevant Recall that TEX passes special information straight to the dvi file That information could easily be special commands which the driver could interpret If we pass PostScript commands then the driver can handle PostScript maybe What if we pass higher level commands which the driver then processes to produce a new dvi file In other words a dvi to dvi processor The new dvi file would among other things be able to be previewed or be sent to any suitable 258 TUGboat Volume 13 1992 No 3 Proceedings of the 1992 Annual Meeting printer provided you had the correct dvi to printer driver So what we end up with is a device independent method There are a couple of attempts to do this There is a program around called dvidvi Rokicki 1989 which processes a dvi file but only so that you can rearrange the pages say to shrink them to thumbnails and arrange them all on a single sheet actually very useful for book make up Mike Spivak 1989 has provided dvipaste which allows you to paste a dvi file into another dvi file so that you can put a table which gobbles up space in TEX where you want equally it could paste in a large picture and that
12. i read me Electronic docu mentation Radical Eye Software 1989 Rokicki Tom DVIPS A TeX Driver Salomon David DDA Methods in TEX TUGboat 10 2 pages 207 216 1989 Schopf Rainer Drawing Histogram Bars inside the IATEX Picture Environment TUGboat 10 1 pages 105 107 1989 Simpson Richard Nontraditional uses of META FONT Pages 259 271 in TX Applications Uses Methods Malcolm Clark ed Chichester England Ellis Horwood Publishers 1990 Ballantyne Michael Michael D Spivak and Yoke Lee HI TEX Cutting amp Pasting TUGboat 10 2 pages 164 165 1989 TUG DVI Driver Standards Committee The DVI Driver Standard Level 0 TUGboat 13 1 pages 54 57 1992 Van Haagen A J Box Plots and Scatter Plots with TEX Macros TUGboat 9 2 pages 189 192 1988 Wichura Michael The PrCIEX Manual TEXniques 6 series Providence Rhode Island TEX Users Group 1987 Wichura Michael P CTEX Macros for Drawing PyCtures TUGboat 9 2 pages 193 197 1988 Wilcox Patricia Metaplot Machine Independent Line Graphics for TEX TUGboat 10 2 pages 179 187 1989 Wujastyk Dominik Chemical Ring Macros in IATEX TEXline 4 page 11 1987 Wujastyk Dominik Chemical Symbols TATEX TpeXline 5 page 10 1987 from 260 TUGboat Volume 13 1992 No 3 Proceedings of the 1992 Annual Meeting
13. igh quality graphs we may be disappointed by the faithful rendition of those 300 dpi blobs and the angular staircasing which is all too obvious at the higher resolution The creation of b zier curves is a remarkable achievement given TRX s limited arithmetic capa bility Adding two numbers together is awkward enough and when we realize that TEX will only use integers in a rather limited range the results are all the more surprising Since the picture environment is rather crude one or two people have put higher level commands around them The two best known are P CTEX and epic PyCTg X Wichura 1987 can be run with both TeX and IATEX Figure 6 The commands for PCIEX are distributed freely but the 85 page manual is essential in order to use it sensibly This article has already loaded quite a few picture drawing commands and many of the allocation registers are becoming filled up While it is no real problem to stick to say the picture environment once we start mixing in extra commands the limitation to 256 counters boxes dimensions and token strings starts to hurt The syntax of the commands required by PjCTRX seems quite reasonable if quirky at times It is no worse than many commercial plotting packages like SAS or SPSS But even if we have enough room for allocation of the registers running with PyJCTRX and LATEX on a 32 bit TREX it is still possible but not easy to exhaust the available memory And given
14. ly undermines TEX s claim to universality TEX is universal but the documents may be restricted to certain versions and you won t necessarily know until you try to process them and run out of memory or not This article is reprinted from Chapter 17 of A Plain T X Primer by Malcolm Clark Oxford University Press 480pp November 1992 e 0 8 x 10 8 e 4 7 x 3 5 e 1 1 5 s 42 e 0 0 x 14 0 e 1 2 5 Figure 1 Simple graphics within TEX All sorts of diagrams have been created using TEX References to some of these are given in the bibliography There are three major ways in which graphics may be made part of TEX documents For simplicity and brevity graphics is restricted principally to line graphics but most of what is covered can be generalized As with most things the more limited the capabilities the closer they may be to universality High degrees of sophistication usually mean greater restrictions are present Attention is directed here to techniques which have some claim to generality the running on my Sun workstation using proprietary software solution is ignored as far as possible The vain hope is that someone working on their Macintosh will be able to exchange TEX documents with someone working on an IBM pc an Amiga an Atari a NeXT a Vax under VMS and so on up the scale until we reach the supercomputer league We do not wish to present solutions which only work on spe
15. metric file Conventionally the route to produce these is METAFONT but there is no particular reason why we should have to adopt this route Provided the tfm and pk contain appropriate information the driver should be able to typeset The underlying idea here is that we can have another program take say a grey scale picture and process it to produce both the required files The tfm file should be simple enough to produce even by hand since we might make this font have only one character at a time The property list would be fairly simple A traditional pixel or px1 file only contains binary information so we are back in the realms of image KEYNOTE ADDRESS Portable Graphics in TEX processing or half toning if we wish to do something rather fancy Most drivers now accept packed pixel rather than pixel information This is simply a far more compact form of the same information Simpson 1990 also describes an application of this approach The example he chooses takes a raster image and turns it into a font The program imtopk converts an IMPART image processing file into a pk tfm pair impart handles the image scaling allowing for device pixel density does any filtering necessary and converts an n level grey scale to two levels TEX positions the image on the page typesets any annotation and handles any other typesetting At Texas A amp M University a similar approach is used where output from a number of gra
16. ost of commands which when examined closely are little specials which do things like draw a line of arbitrary slope through PostScript commands Now T X does not process anything therefore TEX s memory does not fill up When printed on a PostScript device the line is there TUGboat Volume 13 1992 No 3 Proceedings of the 1992 Annual Meeting 257 Malcolm Clark Unfortunately only a few screens are PostScript devices and so we don t usually expect to see these elements previewed One other disadvantage of using specials is that the form of specials is by no means standardized Although there is a working party TUG 1992 attempting to standardize and issue recommendations they are facing the usual problems of standardization committees One of the recommendations is that a level 0 driver should be able to place at least 1000 rules and 20 000 characters on a single page unless the output device is constrained in some way On board device memory may be limited and limit these ideal minima Recall that well over half of the drivers written for use with TeX reside in the public domain No commercial forces come into play with them nor can the TEX Users Group impose rules it is there to serve its members not police them in general this sort of anarchy works since there is enough goodwill around What we are coming to is the fact that specials have to be written with a specific driver in mind To give an exampl
17. phics programs but especially the graphics software package Disspla is processed to produce the pk tfm pair This has some appeal since Disspla runs on a very wide variety of machines and may even be called from programming languages A drawback of this approach is that it is difficult to annotate the diagrams with fonts similar to the ones used in the TeX document Special Now to the less general any sort of material may be incorporated in a special Whatever appears there is passed directly to the dvi file where it will be handled by the dvi driver For example we could have PostScript commands in there or even a reference to a file containing a PostScript created graphic The problem is that you also need a driver which knows what to do with the information and a device printer screen which can display the information While PostScript is described as a de facto standard not everyone has access to a PostScript device and in fact more Hewlett Packard and compatible machines are out there in the real world than anything else This actually opens up another route While we could easily include a complete graphic produced by another approach one of the vast array of graphics packages which will produce PostScript and probably scale or otherwise modify it we can also pass simpler information to the dvi file for processing by the driver Maus and Baker 1986 extended the IATEX picture environment by adding a whole h
18. r Dvilaser PS Extensions to ATEX TUGboat 7 1 pages 41 47 1987 Murray Peter and Linda Murray The Art of the Renaissance London Thames amp Hudson 1963 Nicole Olivier A Graphic Driver to Interface Statistical Software S with P CTEX TUGboat 12 1 pages 70 73 1990 Norris A C and A L Oakley Electronic Publish ing and Chemical Text Processing Pages 207 225 in TEX Applications Uses Methods Malcolm Clark ed Chichester England Ellis Horwood Publishers 1990 Olejniczak Burkert Rolf texpic User Manual 1 0 Interplan TB Software GmbH 1990 Olejniczak Burkert Rolf texpic Design and Implementation of a Picture Graphics Language in TREX la pic TUGboat 10 4 pages 627 637 1989 Personal TEX Inc PTI Laser PS Manual 1987 Pickrell Lee S Combining Graphics with TEX on IBM PC Compatible Systems and LaserJet Printers TEX Users Group 11 1 26 31 1990 Podar Sunil Enhancements to the Picture Environment of IATRX Technical Report 86 17 Department of Computer Science SUNY 1986 Rahtz Sebastian A Survey of TEX and Graphics CSTR 89 7 Department of Electronics amp Computer Science University of Southampton 1989 Ramek Michael Chemical Structure Formulas and X Y Diagrams with TeX Pages 227 258 in TEX Applications Uses Methods Malcolm Clark ed Chichester England Ellis Horwood Publishers 1990 Rokicki Tom dvidv
19. re or software An alternative use of METAFONT is to view it as a means of describing an arbitrary picture not a typeface All the tools are there to do it and in fact it is really a lot simpler than creating fonts Of course you do not really do it in METAFONT you do it in something else which is then translated to METAFONT The something else at the moment is one of several programs by Rick Simpson Simpson 1990 which works on the IBM RT running AIX a UNIX lookalike or Metaplot Pat Wilcox 1989 This latter was written in C and is available in a number of forms There is at least a pc version an Amiga version and lots of UNIX versions In both cases what comes out at the far end is a single very large character or even a set of characters which are tiled together which you plot wherever you want The disadvantage is that scaling the picture is tedious just like scaling a normal character and editing it requires a re run 256 TUGboat Volume 13 1992 No 3 Proceedings of the 1992 Annual Meeting of METAFONT But it is device independent The only proviso is that the device driver be able to handle these very large characters This is not a trivial expectation since many drivers were written expecting that they would be dealing with letters and that there was some reasonable maximum size to a letter Wilcox did not really expect the user to write in her Metaplot The notion was that a variety
20. scussing the use of special fonts Of course we can also generate our own There are two different directions here On the one hand we can use some suite of other fonts on the other we could generate METAFONT descriptions somehow and use those descriptions In both cases there is appreciable generality In the final analysis METAFONT is as portable as TeX and once the descriptions are made available we are CH O Figure 8 Caffeine as free to use those as we would be to use IA TEX commands Knuth 1987 introduced some halftone fonts which allow greyscale pictures to be typeset in a completely device independent way Adrian Clark 1987 also made some contribution to this and Hoenig 1989 shows some interesting examples Since the descriptions are available anyone may borrow them quite easily Adrian used a FORTRAN program as a pre processor This is fair since for all sorts of reasons we would normally expect the data to be provided in a digital form from some other source There are problems of TEX memory here again Even with a big version TEX may only handle one 512 x 512 picture or four 256 x 256 pictures Knuth s paper discusses some manipulation techniques which would allow greater clarity from lower resolution pictures This is a fairly general and well understood aspect of image processing which need not concern us here The point is that it is quite possible and represents no new addition of hardwa
21. stinctly squared graph paper feel But it is certainly possible to create quite attractive graphs Any vertical and horizontal elements are just standard TEX rules while rounded corners and circles can be made from the IATRX circle fonts Y Figure 2 A small range of diagonals is possible through other special line fonts lll The IATEX picture environment is amazingly modular In other words you can rip it out of TATEX and run it in plain TeX using the same basic commands which are documented in the IATEX book Although creating pictures this way is time consuming it can give quite pleasing quality at least on the laser printer Quite acceptable bar charts may be created as Nagy 1989 shows Figure 3 It is possible to tackle chemistry through the use of these fonts as Figure 4 demonstrates In this case some of the tedium is removed by creating the ring structure only once storing it in a box and then copying that box when it is needed Besides making the procedure less long winded it cuts down on the effort needed by TEX itself since copying a box requires no new manipulations The creation of diagrams like this can be amazingly tedious but the approach still achieves a generality and portability which cannot be ignored Interactive preprocessor Photographs Maths amp text type setting language scanner e g TEX Word Processor Illustrations e g WordPerfect e
22. the amount of arithmetic going on in the background these diagrams tend to be slow 255 Malcolm Clark 1 20 1 Xm 1 15 1 10 1 05 75 0 80 0 85 0 90 0 95 0 100 0 T K Figure 7 Reciprocal magnetic suscepti bility from Ramek 1990 Olivier 1989 describes an amalgam between S the UNIX statistical package and PJCTEX Clearly this is restricted to UNIX in the first instance although the PICTEX would be portable Although epic Podar 1986 was targeted for LATEX it can also be used in TeX It lacks the generality of P CT X but is a useful extension Podar added some higher level commands in order to provide a friendlier and more powerful users interface In particular he managed to reduce the amount of manual calculation required For example he introduced a drawline command which allows specified points to be connected In order to avoid the problem of slope segments outside IATEX s ability he uses the closest slope available This can lead to rather jagged lines If the lines are dashed this problem appears less acute There are several collections of commands which draw all sorts of rather nice graphs My favourites are those of Michael Ramek Ramek 1990 Figure 7 is taken from his paper and helps illustrate the scope that is possible Besides the normal graph requirements he provided some other commands to draw chemical structures as shown in Figure 8 Other fonts So far we have been di
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