============================================================================== RED CIENTIFICA PERUANA ============================================================================== -- PostScript -- Answers to Questions (the comp.lang.postscript FAQ v2.0) 1992-10-29 Jon Monsarrat jgm@cs.brown.edu This FAQ is formatted as a digest. Most news readers can skip from one question to the next by pressing control-G. CHANGES since the last version: Everything has changed. Please help fix the FAQ! All comments should be mailed to jgm@cs.brown.edu. My favorite way to receive a change suggestion is when it is accompanied by a section of the FAQ that is edited and mailed to me verbatim as an example. If you would like to contribute, please read the section ``about the FAQ'' first. Thank you! Books and programs are referred to by name only. See the appropriate sections for full information. I have archived a number of the small utilities in wilma.cs.brown.edu:pub/postscript. Related FAQs: comp.text, comp.text.tex, comp.fonts, comp.graphics, Table of Contents This FAQ has 12 sections. It may only be appropriate to post 4 or 5 of them to the newsgroup (the rest would be available by ftp). Please voice your opinion about this to me. The FAQ is available by anonymous ftp to wilma.cs.brown.edu:pub/comp.lang.postscript in ASCII, LaTeX, DVI, and PostScript formats. 1 General Questions 1.1 What is PostScript? 1.2 How can I tell how many pages my document will have? 1.3 How can I print just one page or a few pages from a big document? 1.4 How can I print more than one page per sheet of paper? 1.5 How can I edit a PostScript picture? 1.6 How can I print PostScript on a non-PostScript printer? 2 Printers 2.1 How can I get my printer to talk back to me? 2.2 Should I leave my printer on? 2.3 How do I suppress the power-on start page? 2.4 How do I remove a persistent (``permanent'') downloaded font? 2.5 How do I reset the printer without power-cycling? 2.6 About saving files 2.7 What's the control-D business? 2.8 Why does the printer say ``still busy'' when my document is done printing? 2.9 How should I set up my spoolers? 3 Formats and Conversions 3.1 How can I convert PostScript to some other graphics format? 3.2 How can I convert DVI to PostScript? 3.3 How can I convert HP Laserjet language (PCL) to PostScript? 3.4 How can I convert TeX PK format to PostScript? 3.5 How do I embed PostScript into troff? 3.6 How do I embed PostScript into LaTeX or TeX? 3.7 How can I convert an image to PostScript? 3.8 How can I convert ASCII text to PostScript? 3.9 How can I convert PostScript to ASCII? 4 Fonts 4.1 What are .PFB and .PFA files? 4.2 How can I convert a PostScript font to TeX's PK format? 4.3 Why are Adobe fonts hidden? 4.4 How do I get bitmap representations of Adobe fonts? 4.5 What are some good ftp sites for fonts? 4.6 How can I re-encode a font? 4.7 What's the difference between a Type 1 and a Type 3 font? 4.8 What vendors sell fonts for PostScript printers? 4.9 What are ATM fonts? 4.10 What are Multiple Master Fonts? 4.11 Do I need a Level Two printer to use Multiple Master Fonts? 4.12 What are Type 4 fonts? 4.13 What are Type 5 fonts? 5 Books 5.1 Books 5.2 Publishers 6 About Adobe 6.1 How do I get in touch with Adobe? 6.2 What can Adobe do for me? 7 Programming in PostScript 7.1 What is PostScript level 2? 7.2 Should I learn level 2 PostScript? 7.3 Where can I find examples of PostScript code? 7.4 How do I get the physical size of a page? 7.5 Why can't I do a pathforall after a charpath ? 7.6 How do I center a string of text around a point? 7.7 How can I concatenate two strings together? 8 Computer-specific PostScript 8.1 Sun Workstations 8.2 IBM PC 8.3 Apple Macintosh 9 Encapsulated PostScript 9.1 What is Encapsulated PostScript? 9.2 How do I convert PostScript to EPS? 9.3 How do I get the bounding box of a PostScript picture? 10 About The Comp.Lang.PostScript FAQ (and Usenet Guide to 10.1 The PostScript FAQ: What is it? 10.2 How to get the FAQ files 10.3 How to write a FAQ answer 10.4 The FAQ can contain LaTeX and PostScript inserts 10.5 Revising the FAQ 10.6 How to submit new information 10.7 How to add a program description to the FAQ index 10.8 How to add a book description to the FAQ 10.9 Questions that need answers 11 About PostScript 2 (Contains 34 detailed sections) 12 PostScript Interpreters and Utilities 12.1 How can I find a program? 12.2 How can I browse through PostScript programs? 12.3 Keywords 12.4 Interpreters 12.5 Utilities Subject: 1 General Questions Subject: 1.1 What is PostScript? PostScript is a graphics programming language. It is perhaps the most popular and versatile language for printers, being used in printers world-wide. It is capable of drawing to computer screens and any kind of drawing device. PostScript is interpreted, stack based and untyped, like the computer language FORTH. A number of programmers write PostScript programs directly for a variety of drawing applications. However, PostScript programs are usually documents meant to be printed that have been generated by a program written in some compiled language. Subject: 1.2 How can I tell how many pages my document will have? The easiest way to count pages is view your document on-line with a PostScript previewer. Some previewers like Ghostview and GSPreview count the pages for you. (See the interpreters in the utilities section.) If your document is generated by a professional program, you should be able to just count the number of ``%%Page:'' comments imbedded in the document. With UNIX you can type grep -c %%Page document.ps to do this counting. (See Encapsulated PostScript in the conversions section.) The only completely reliable way to count pages is to ask the printer. PostScript printers maintain a page counter that can be queried before and after the job is printed, and the page count is a simple subtraction. This tends to require rather sophisticated spooling systems and a communications channel that is bidirectional. However, some printers allow you to submit jobs on one port, and issue queries on another. Experts using a level 2 printer can use the SerialOff.PS and SerialEHandlder.ps programs to communicate bidirectionally to the printer. Subject: 1.3 How can I print just one page or a few pages from a big document? How can I print pages in reverse order? Try using a host-specific program, like the UNIX command psrev. Or use the more general utilities Ghostview, psutils or psxlate. There is no guarantee that a given PostScript document can be split in such a manner. The reason is that some programs which generate PostScript code don't conform to the Adobe Document Structuring Conventions (DSC). (See the Encapsulated PostScript section.) A notable example of this is Microsoft Word. Subject: 1.4 How can I print more than one page per sheet of paper? Use psnup or pstext. These programs redefine the PostScript ``showpage'' command to do multiple PostScript pages per physical page. If one program doesn't work with a complex document, try out other ones. Subject: 1.5 How can I edit a PostScript picture? If you know the PostScript programming language, just use any text editor to edit the code directly. If you want to do it visually, you can use Canvas on the Macintosh. Subject: 1.6 How can I print PostScript on a non-PostScript printer? You need a tool that converts to something that your printer knows how to print. Use Freedom of the Press, GhostScript, hp2pbm, pageview, TScript, or UltraScript. Subject: 2 Printers Subject: 2.1 How can I get my printer to talk back to me? Experts using a level 2 printer can use the SerialOff.PS and SerialEHandlder.ps programs to communicate bidirectionally to the printer. Subject: 2.2 Should I leave my printer on? Yes. The general consensus seems to be that most computer equipment lasts longer if left on. This presents less thermal stress to the components. Subject: 2.3 How do I suppress the power-on start page? Disabling the start page is described in your printer's PostScript supplement. The most common sequence is ``serverdict begin 0 exitserver statusdict begin false setdostartpage end''. Subject: 2.4 How do I remove a persistent (``permanent'') downloaded font? One trick for removing a persistent font (this requires that you knew you would need to remove it before you downloaded it) is to issue a ``serverdict begin 0 exitserver /magic-cookie save def'' before downloading and sending ``serverdict begin 0 exitserver magic-cookie restore'' when you want to reclaim all VM used since the first download. The downside of this is that is uses up a save level, but this is usually not a problem. Subject: 2.5 How do I reset the printer without power-cycling? Most printers can be reset by issuing "serverdict begin 0 exitserver systemdict /quit get exec". Subject: 2.6 About saving files Adobe recommends that driver writers do not put EOT (control-D) into files when saving to disk. Normally, the EOT is a part of the protocol for parallel and serial ports and never hits the PostScript interpreter. Drivers that do embed EOD can create problems for devices that allow other communication methods (e.g. AppleTalk, Ethernet, and SCSI) where the EOT is not part of the communications protocol. It is useful to redefine EOT in these instances so that the interpreter does not generate an error. The recommended redefinition is: (\004) cvn {} def This should convert any stand-alone embedded EOTs into a null procedure. Subject: 2.7 What's the control-D business? After sending the raw file to the raw device, it's necessary to send a control-D. This is the job of the print service, but if you're unsure whether your print service is doing it, it's an idea to send one yourself. Also, some programs like Framemaker send a control-D as the first character in the file, presumably to flush out any other jobs, thereby breaking the Adobe Document Structuring Conventions. Subject: 2.8 Why does the printer say ``still busy'' when my document is done printing? Sometimes when you finish a print job, the printer "Ready" light keeps flashing for a minute or so. Somehow, the printer has received some character(s) after the control-D which was sent immediately after the PostScript file. The printer took these character(s) to be another program, and eventually timed-out while waiting for the rest of it. Subject: 2.9 How should I set up my spoolers? Since PostScript usually is prefixed with ``%!'', it's easy to educate your spooler to autoselect between passing raw PostScript through to the printer or doing an "ASCII-to-PostScript" conversion first. There are many packages that will do this, including Transcript and psxlate. Unfortunately, many PostScript applications generate PostScript without a proper "%!" magic cookie. The spooler should be responsible for transmitting the ``job termination code'' (a control-D on serially-connected printers) to the printer, not the application. Do yourself a favor and disable (or filter out) control-Ds in your applications and generate them in the spooler. This will be far more reliable in the face of arbitrary input. Subject: 3 Formats and Conversions This section describes all formats that can be converted to and from PostScript, and how to convert them. Encapsulated PostScript and Fonts have their own sections. Subject: 3.1 How can I convert PostScript to some other graphics format? Since PostScript is not just a picture-description language, but in fact a complete programming language, you will need a complete PostScript interpreter to convert or display a PostScript graphic. (See the section on interpreters.) Try using TranScript. Subject: 3.2 How can I convert DVI to PostScript? Use dvips. Subject: 3.3 How can I convert HP Laserjet language (PCL) to PostScript? Use lj2ps for simple PCL. Alternatively, another lj2ps, from psroff3.0, is a little more complete. hp2pbm can convert all of PCL4 (up to and including rasters, downloaded fonts and macros). Subject: 3.4 How can I convert TeX PK format to PostScript? Psroff3.0 contains programs that can convert TeX PK format or HP SFP format fonts into PostScript bitmap fonts. While bitmap bfonts scale poorly, this is sometimes of use in special circumstances. Subject: 3.5 How do I embed PostScript into troff? Most troffs can be ``coerced'' into including PostScript figures. The best approach is a configuration that takes EPS PostScript and can automatically scale it, or tell troff how big the picture is. Groff and DWB 3 have this built in. psfig is an add-on EPS inclusion handler that can add this capability to other versions of troff, provided that a compatible PostScript driver is used (Psroff 3.0 for ditroff or CAT troff, Transcript for ditroff). See the comp.text FAQ for more detail. Subject: 3.6 How do I embed PostScript into LaTeX or TeX? You should use an add-on program for seamless PostScript inclusion. For generic PostScript in a professional document, use psfig. If your LaTeX is simple, but your PostScript is fancy, try using LameTeX. If you need a good compromise, use pstricks. For more detail, see the comp.text.tex FAQ. Subject: 3.7 How can I convert an image to PostScript? Try PBMPLUS. To convert an image to PostScript in X windows, you can display the image on the screen and then use ``xpr -device ps'' in the resulting X11 window. For example, to convert GIF to PostScript, use xv or xshowgif (ftp from bongo.cc.utexas.edu (128.83.186.13)) and then xpr. A more general alternative in X windows would be to use the PPM, PGM and PBM utilities in the X11R4 and X11R5 distributions. Subject: 3.8 How can I convert ASCII text to PostScript? Unless your printer is smart about raw ASCII, you can't just send the ASCII to a PostScript printer, because the printer will attempt to interpret your ASCII file as PostScript code. You need a program which will wrap some PostScript code around your ASCII file. Try any of the following programs: asciiprint.ps, ato2pps, cz, ETSR, i2ps, lpp, lwf, POSTPRN, printer, psf, psfx80, PSR, ps2txt, pstext, swtext, text2ps, TranScript, spike.ps, enscript, nenscript, a2ps, asc2ps, ascii2ps, crossword.ps, double.ps, landscape.ps, numbered.ps, portrait.ps, or wide.ps. Subject: 3.9 How can I convert PostScript to ASCII? Use ps2a, ps2ascii, ps2txt, ps2ascii.ps or ps2ascii.pl. For UNIX users, the following csh command will extract all of the strings from a PostScript file and print them. % usage: unps < infile.ps > outfile.txt alias unps (sed \ \''s/%.*$//g;s/^[ \t]*[^()]*$//g;s/^[^(]*(//g;s/)[^(]*(/ /g;s/)[^)]*$//g;'\' \ \| tr '"012' '"040' \| tr -s '"040' '"040' \; echo \'\') Subject: 4 Fonts This section answers questions about fonts as they pertain to PostScript. See the comp.fonts FAQ for more information about fonts. Subject: 4.1 What are .PFB and .PFA files? ``PFB'' stands for Printer Font Binary, and is a binary format in which Adobe Type 1 font programs are usually distributed. Many application programs support fonts in this format, and refer to them as ``downloadable''. The PFB format is described in ``the black book''. PFB files are compressed, and as a result, cannot be sent directly to a PostScript printer. Application programs like dvips which use fonts in this format uncompress the font before sending it to the printer. If you would like to use a font which is in PFB format, it is necessary to uncompress it first, to make a PFA file. ``PFA'' stands for Printer Font Ascii, which is the uncompressed version of a PFB file. Once you have the PFA file, just send it to the printer ahead of your file, and use the font like any other. There are several programs which can do the conversion from PFB to PFA for you. Try t1utils. Subject: 4.2 How can I convert a PostScript font to TeX's PK format? Use ps2pk or try out the GNU font utilities in fontutils. Subject: 4.3 Why are Adobe fonts hidden? In PostScript level 1, Adobe's fonts were hidden because they didn't want people pirating copies instead of paying for them. That's why you can't do a pathforall on a charpath. PostScript Level Two has removed the restriction, in the words of the new Red Book, ``for most fonts''. There will still be some vendors who will want to restrict access. Most of the Japanese font vendors, for example, are paranoid about piracy -- given the work that goes into an 8,000-character Kanji font. Subject: 4.4 How do I get bitmap representations of Adobe fonts? Use the Font Foundary program included with the font. If you don't have it, contact Adobe for an upgrade. Subject: 4.5 What are some good ftp sites for fonts? ftp.cs.umb.edu sumex-aim.stanford.edu archive.umich.edu ftp.cica.indiana.edu /pub/pc/win3/fonts colonsay.dcs.ed.ac.uk /pub/postscript/fonts yak.css.itd.umich.edu For the NeXT platform, fonts are available on the NeXT-FTP-archives, sonata.cc.purdue.edu :/pub/next/graphics/fonts fiasko.rz-berlin.mpg.de :/pub/next/fonts For Macintosh, look in sumex-aim.stanford.edu, mac.archive.umich.edu, and ftp.cs.umb.edu (192.12.26.23), in pub/tex/ps-screenfonts.tar.Z. Color PostScript samples and many other PostScript programs are available from irisa.irisa.fr. Subject: 4.6 How can I re-encode a font? See ddev.ps for an example for code that does this. Subject: 4.7 What's the difference between a Type 1 and a Type 3 font? The Type 1 font format has nothing to do with TrueType, which is another font format defined by Apple. The Type 1 font format has been around quite a while, and is used on a wide variety of platforms to obtain scalable fonts. The Type 1 font format is a compact way of describing a font outline using a well-defined language that can be quickly interpreted. The language contains operations to provide the rasterizer with additional information about a character, known as hints. The Type 1 font format is defined in the book "The Adobe Type 1 Font Format", also known as the black-and-white book, for the colors on it's cover. Most clone interpreters will not have Adobe's proprietary rendering technology which interprets font hints to improve the appearance of fonts shown at small sizes on low-resolution devices. The exceptions are PowerPage and UltraScript. The Type 3 font format is a way of packaging up PostScript descriptions of characters into a font, so that the PostScript interpreter can rasterize them. It is often easier to create a Type 3 font program by hand than to create the corresponding Type 1 font program. Type 3 font programs have access to the entire PostScript language to do their imaging, including the 'image' operator. They can be used for bitmapped fonts, although that is certainly not a requirement. The Type 3 font format contains no provisions for 'hinting', and as such Type 3 font programs cannot be of as high a quality at low resolutions as the corresponding Type 1 font program. Both formats are scalable formats, and both can be run on any PostScript interpreter. However, because of the requirement that a Type 3 font program have a full PostScript interpreter around, Type 3 font programs cannot be understood by the Adobe Type Manager. Only Type 1 font programs can. Because of Adobe Type Manager's wide availability on a large number of platforms (PC, Mac, and Unix), the Type 1 font format makes an excellent cross-platform scalable font standard. Subject: 4.8 What vendors sell fonts for PostScript printers? PostScript font vendors are many and varied. Here is a partial list. Adobe Systems sells a variety of fonts. With the huge number of third-party Type 1 vendors, in recent years Adobe have specialized in creating their own ``Adobe Originals'' -- high-quality fonts, some of which are their renditions of classic faces (Adobe Garamond) and some of their own devising (Stone, Utopia, ...). Adobe Systems, 1585 Charleston Road, Mountain View, CA 94039. (415) 961-4400 AGFA Compugraphic, 90 Industrial Way, Wilmington, Massachusetts 01887. (508) 658-5600. Bear Rock Technologies specializes in bar code fonts. Enterprise Drive, Diamond Springs, California 95619. Bitstream, Athenaeum House, Cambridge, MA 02142. (617) 497-6222. Casady and Greene, 22734 Portola Drive, Salinas, CA 93908. (408) 484-9228. Ecological Linguistics, specializes in non-Roman alphabets. Ecological Linguistics, P. O. Box 15156, Washington D. C. 20003. Image Club, # 5 1902 11th St Southeast, Calgary, Alberta T2G 2G2, Canada. (403) 262-8008. Lanston specializes in display faces. Letraset specializes in fancy kinds of script fonts, Letraset, 40 Eisenhower Drive, Paramus, New Jersey 07652. (201) 845-6100 Linguists Software specializes in non-Roman alphabets (Farsi, Greek, Hangul, Kanji, etc.) Linguists Software, P. O. Box 580, Edmonds, Washington 98020-0580. (206) 775-1130. Linotype Monotype, 53 West Jackson Boulevard, Suite 504, Chicago, IL 60604. Page Studio Graphics, Chandler, Arizona, specialize in symbols fonts such as Mac icons, keyboards, and others, Page Studio Graphics, 3175 North Price Road, # 1050, Chandler, Arizona 85224. (602) 839-2763. RightBrain Software, Palo Alto, CA (415 326-2974) carry the Adobe Type library for the NeXT platform. If you're working on NeXT, getting fonts in the correct form with all the ancillary information and downloaders and such is important. You can convert a Mac font to NeXT (PFA) format, but the NeXT demands an AFM file as well, and many Mac/PC font vendors omit AFM files because Mac/PC apps don't use them. For Adobe fonts for the NeXT, save yourself a lot of hassle by getting the fonts from RightBrain -- they often have sales. The Font Company TreacyFaces URW supplies high-quality fonts at low prices. They are also the creators of the top of the line font creation and editing software called Ikarus. URW, 4 Manchester Street, Nashua, New Hampshire 03060. (603) 882-7445. Many more font vendors exist. Look in magazines and other sources. Look in U & lc, published by ITC, for long lists of vendors. Subject: 4.9 What are ATM fonts? There has been a rash of misunderstanding about the nature of Type 1 fonts and what people call ATM fonts. ATM fonts are Adobe Type 1 fonts. ATM stands for Adobe Type Manager -- a utility to render smooth characters on Macintosh and PC screens, from font outlines (Type 1 fonts) instead of using bitmap fonts. In one sense, there's no such thing as an ``ATM font'' -- ATM interprets Type 1 fonts, so there's no need to create a new name. A correctly constructed Type 1 font can be interpreted by ATM. Subject: 4.10 What are Multiple Master Fonts? Multiple Master Fonts are an extension to the Adobe font format. providing the ability to interpolate smoothly between several ``design axes'' from a single font. Design axes can include weight, size, and even some whacko notions like serif to sans serif. Adobes' first Multiple Master Font was Myriad -- a two-axis font with WEIGHT (light to black) on one axis, and WIDTH (condensed to expanded) along the other axis. In the case of Myriad, there are four ``polar'' designs at the ``corners'' of the design space. The four designs are light condensed, black condensed, light expanded, and black expanded. Given polar designs, you can set up a ``weight vector'' which interpolates to any point within the design space to produce a unique font for a specific purpose. So you can get a ``more or less condensed, somewhat black face''. Subject: 4.11 Do I need a Level Two printer to use Multiple Master Fonts? No -- Multiple Master Fonts can be used on any PostScript printer. Multiple Master Fonts need a new PostScript operator known as makeblendedfont. The current crop of Multiple Master Fonts supply an emulation of this operator so the printer doesn't need this operator. A short tutorial on Multiple Master Fonts and makeblendedfont appears in PostScript by Example, by Henry McGilton and Mary Campione, published by Addison-Wesley. Subject: 4.12 What are Type 4 fonts? Type 4 fonts are actually Type 1 fonts, but stored on hard disk in a special way to save space when they're loaded into printer RAM by findfont. Subject: 4.13 What are Type 5 fonts? Type 5 fonts are actually Type 1 fonts, but stored in printer ROM in a special compressed format. They're also known as CROM fonts (for Compressed ROM fonts). Acknowledgments This FAQ was compiled based heavily on the contributions of and with the help of Henry McGilton, Howard Gayle, Carl Orthlieb, Ed Garay, Robert Lerche, Bruno Hall, and Chris Lewis. Also thanks to contributors Charles Cashion, Jim DeLaHunt, Karl Berry, Chris Herborth, Jamie Zawinski, Timo Lehtinen, Jerry Black, Dug Scoular, Leonard Hamey, Bill Pringle, Carl Lydick, Elliotte Harold, Bill Lee, and Tony Valsamidis. I'm also grateful for the advice of Steve Kinzler and Dick Dunn. Special thanks to Ken Porter, who originally compiled and organized this FAQ. Ver Date Reason ---------------------------------------------------------------- 1.00 12-18-90 Creation by Ken Porter 1.06 5-29-91 expanded on EPS explanation, general updates 2.00 10-25-92 Brought up to date and expanded, by Jon Monsarrat Parts of this FAQ are copyrighted by other people, and the rest is Copyright (C) 1992 by Jonathan Monsarrat. Permission is granted to freely edit and distribute as long as this copyright notice is included. This document was written with the LaTeX language and formatted by LameTeX, the PostScript hacker's LaTeX. Jonathan Monsarrat %! jgm@cs.brown.edu -- Brown University Computer Science Department -- %! Obfuscated PostScript /r{repeat<267F>ge{pop}if}def/dup{pop}def/cvx{show}def /p{translate}def/y{-1 roll exec}def{<2020202020666F6E74>dup 0 4 y putinterval cvx 0 y}dup dup/Times-Roman<2066696E64>3 y 100<7363616C65>4 y<2020736574>3 y 90 rotate 0 -612 p 1 1.8 scale 36 144 moveto <50532020202020207B484F4E4B7D2069 66> show gsave 220 130 p {0 0 moveto 29 58 29 -45 180 arc} cvx dup 0 y -1 1 scale 0 y gsave 0.6 setgray fill grestore 2 setlinewidth stroke showpage Subject: 5 Books There are many good books on PostScript language programming. Descriptions of all known books are listed below. A listing of publisher information follows. The most commonly known books are the ``blue book'', ``red book'', and ``green book'' from Adobe, to be read in that order. They are nicknamed according for their jacket colors. Other books recommended to me include Thinking in PostScript and PostScript by Example. Subject: 5.1 Books Adobe Accurate Screens explains in detail all the issues and specifically covers Adobe Accurate Screens -- Adobes' own screening technology. Peter Fink is an expert on the subject of halftone screens as they relate to color issues. Author: Peter Fink Publisher: Adobe Press, 1992. ISBN 0-672-48544-3 Library Call # ??? Adobe Illustrator 88, The Official Handbook for Designers ??? Authors: Tony Bove, Cheryl Rhodes, Fred Davis Publisher: Bantam Computer Books 1987. ISBN ??? Library Call # ??? Adobe Type 1 Font Format, ``the black book'' This is the specification for the Type 1 font format. Type 1 fonts are the standard outline format found in Adobe PostScript printers, implementations of the Display PostScript system, and available as downloadable fonts from the Adobe Type Library. This document describes the syntax of the Adobe Type 1 font format, including complete information regarding hints, encoding of character outlines, and the charstring and eexec encryption algorithms. Author: Adobe Systems Inc Publisher: Addison-Wesley, 1990. ISBN 0-201-57044-0 Library Call # ??? Display PostScript Programming ??? Author: David A. Holzgang Publisher: Addison Wesley, 1990 ISBN ??? Library Call # ??? Encapsulated PostScript: Application Guide for the Macintosh and the PC has its focus is EPS. However, it is an excellent book full of actual real life PostScript and Encapsulated PostScript applications on Macs, PCs, Unix, IBM mainframe, and other computer systems. Author: Peter Vollenweider Publisher: Prentice Hall 1990 ISBN 0-13-275-843-1 Library Call # ??? Graphic Design With PostScript ??? Author: Gerard Kunkel Scott Publisher: Foresman and Company, 1990 ISBN 0-673-38794-1 Library Call # ??? Hands On PostScript ??? The code is included with the price of the book ( $ 29.95). Author: Michael Spring Publisher: ??? ISBN ??? Library Call # ??? Inside PostScript essentially takes one on a tour of the standard internal PostScript code in most printers. The author spelunked around in the interpreter and figured out how most normal stuff worked (in PostScript terms, no low-level hardware stuff here like cexec and internaldict). Author: Frank Merritt Braswell Publisher: Systems of Merritt & Peachpit Press 1989 ISBN 0-938151-10-X Library Call # ??? Cost: about $ 40. Learning PostScript, A Visual Approach is a tutorial on the PostScript language. It is very appealing, very easy to follow and filled with examples. Each example occupies two pages. A brief explanation and source code is on the left page, and the resultant print-out is on the facing right page. The book starts off very simply for beginners, and covers a lot of material at the end for experts. It does not cover level 2 PostScript. In the later half of the book, a few examples can executed only if an additional book is purchased. The code for LPAVA is $ 20 from Smith Consultants, 834 Third st, Suite B, Santa Rosa, CA 95404, U.S.A. fax number: 415-524-9775 Author: Ross Smith Publisher: Peachpit Press, 1990 ISBN 0-938-151-12-6 Library Call # ??? Cost: $ 22.95 Mastering Adobe Illustrator ??? Author: David A. Holzgang Publisher: Addison Wesley, 1988 ISBN ??? Library Call # ??? Mastering Adobe Illustrator 88 ??? Authors: Deke McClelland and Craig Danuloff Publisher: Publishing Resources Inc.-Dow Jones Irwin 1989 ISBN ??? Library Call # ??? PostScript by Example is a tutorial for PostScript people at all levels. It covers level 2 PostScript. The book starts at novice level and works through to Level Two composite fonts, patterns, forms, color, halftones, Display PostScript rectangle operators and text operators. It contains a chapter on practical issues of downloading fonts, talking to printers, and error handling. 640 pages containing over 500 fragments of PostScript code and over 750 illustrations. A long-awaited ``upgrade'' to the Blue Book. Henry McGilton can be reached by email as henry@trilithon.mpk.ca.us. A disk containing 13,000 lines of PostScript code from the book can be ordered separately for $ 20 from: Trilithon Software, Two Ohlone, Portola Valley CA 94028, U.S.A. Or, send E-mail to info@trilithon.mpk.ca.us. Authors: Henry McGilton and Mary Campione Publisher: Addison Wesley, 1992. ISBN 0-201-63228-4 Library Call # ??? A PostScript Cookbook ??? Author: Barry Thomas Van Nostrand Reinhold Publisher: ???, 1988. ISBN ??? Library Call # ??? PostScript Language Program Design, ``the green book'' is intended to teach the fundamentals of designing PostScript language programs and to show how the language works, so the your programs will be fast, well-behaved, easy to understand, and portable. Code Examples: $ 15 from the developer support hotline. Free from the Adobe mail server (see the section on Adobe). Author: Adobe Systems Incorporated Publisher: Addison Wesley 1988 ISBN 0-201-14396-8 Library Call # ??? Cost: $ 22.95 PostScript Language Reference Manual (2nd ed), ``the red book'' is the book that defines the PostScript language. The second edition not only defines Level 1 PostScript, but also encompasses the color, composite font, file system, and DPS extensions and the PostScript language Level 2. Author: Adobe Systems Incorporated Publisher: Addison Wesley 1985, 1990 ISBN 0-201-18127-4 Library Call # QA76.73.P67P67 Cost: $ 28.95 PostScript Language Reference Manual (1st ed), ``the old red book'' is the first edition of the reference manual. It describes PostScript level 1 only. It is a subset of the PostScript level 2 book, but is still more common and costs less. Author: Adobe Systems Inc. Publisher: Addison-Wesley, 1985. ISBN 0-201-10174-2 Library Call # ??? PostScript Language Tutorial and Cookbook, ``the blue book'' is the most common tutorial book on PostScript. It provides an easy, informal introduction to the PostScript language and graphics primitives. The cookbook is a collection of programs that are offered as examples of PostScript usage. These samples have been chosen both as illustrations of the functional range of PostScript and as useful ingredients for inclusion in application packages. Code Examples: $ 15 from the developer support hotline. Free from the Adobe mail server (see the section on Adobe). Author: Adobe Systems Incorporated Publisher: Addison Wesley 1985, 1990 ISBN 0-201-10179-3 Library Call # : QA76.73.P67P68 Cost: $ 16.75 Programming the Display PostScript System with NeXTstep, ``The Purple Book'' is written for the NeXT programming environment; however, much of the information it contains applies to all Display PostScript developers. The book explains the language extensions commonly used within applications, describes many of the key aspects of the PostScript language imaging model, and provides a framework for creating Display PostScript language applications. Author: ??? Publisher: ??? ISBN 0-201-58135-3 Library Call # QA76.73.P67P76 Cost: U.S. $ 26.95 $ CDN 34.95 Real World PostScript: Techniques from PostScript professionals - ``The Orange Book'' is a collection of articles dealing with 'real world' PostScript language issues and specific applications such as font creation, color separation, kerning, halftoning, various other topics. It contains a text formatter written in PostScript, and concentrates on doing very sophisticated things with fonts and dictionaries. Short overview of chapters: PostScript As A Design Tool; PostScript As A Programming Language; Writing Device Independent PostScript; Kerning, Tracking And Letterspacing, Precise Character Bounding Boxes; Building Fonts; Building Smart Fonts; Font Encoding Vector Compatibility; Building A PostScript Typeface; PostScript Color Operations; PostScript Color Separations; A Spread From Graphic Perspective; A PostScript Four-Color Poster; Graphing And Typesetting With PostScript; The Evolution Of A Complex Geometric Logo Author: Stephen F. Roth, editor. Publisher: Addison Wesley, 1988. ISBN 0-201-06663-7 Library Call # Z286.D47R4 1988 Running PostScript from MS-DOS provides a good and brief introduction to PostScript and has lots of useful information on printing PostScript from PCs. Author: Gary Glover Publisher: Windcrest Books, 1989. ISBN 0-8306-2998-X Library Call # : ??? Taking Advantage of PostScript is very graphically and visually oriented and includes a section on PostScript Level 2. Author: John F. Sherman Publisher: Wm. C. Brown Publishers, 1991. ISBN ??? Library Call # : ??? Thinking in PostScript comes recommended, but I do not have a writeup for it. Author: Glenn C. Reid Publisher: Addison-Wesley, 1989 ISBN 0-201-52372-8 Library Call # : ??? Understanding PostScript ??? Author: David A. Holzgang Publisher: Sybex, 1988 ISBN ??? Library Call # : ??? Understanding PostScript Programming, Second Edition ??? Author: David Holzgang Publisher: Sybex, 1988. ISBN 0-89588-566-2 Library Call # : ??? The Verbum Book of PostScript Illustration Authors: Michael Gosney, Janet Ashford, and Linnea Dayton Publisher: M & T Books, 1990. ISBN ??? Library Call # : ??? Subject: 5.2 Publishers Most of the above books should be available in any big bookstore that has a computer section. Or contact the publishers: Addison-Wesley, Retail Sales Group, Addison-Wesley Publishing Company, Inc., One Jacob Way, Reading, MA 01867, U.S.A. Phone 800-447-2226 or 617-944-3700, Fax 617-942-1117. Addison-Wesley Publishing Company, 2200 Powell Street, Emeryville, California 94608 (510) 601-4000 Adobe Press ??? Bantam Computer Books ??? Peachpit Press, 1085 Keith Ave., Berkeley, CA 94708, U.S.A. 800-283-9444, or 415-527-8555. Prentice Hall ??? Foresman and Company ??? Publishing Resources Inc.-Dow Jones Irwin ??? Windcrest Books ??? Sybex ??? You can purchase the red, blue, green, and black books from Adobe Systems by calling 800-83-FONTS. Subject: 6 About Adobe PostScript was created by Adobe Systems Incorporated, which offers information and sells programs pertaining to PostScript. Currently the only large PostScript company that I have information on is Adobe. I would be happy to include information about others. Subject: 6.1 How do I get in touch with Adobe? Adobe Systems Incorporated Main phone: +1-415-961-4400 1585 Charleston Road Main FAX: +1-415-961-3769 P.O. Box 7900 Mountain View, CA 94039-7900 If you want technical help using Adobe retail products (e.g. ATM, Adobe Illustrator, Adobe Fonts): Adobe forum on CompuServe, call +1-415-961-0911 (for Macintosh) or +1-415-961-4992 (for Windows, Unix) Also use this number to report bugs in retail products. For sales information on Adobe retail products (prices, catalogues, etc.), call +1-800-235-0078 (fax-back brochures) or +1-800-833-6687 (applications sales) The Developer's Hotline is +1-415-961-4111 (Voicemail) (note: members have priority, but they'll take questions from general public.) Also use this number for information about the ADA or Adobe SDK's. To suggest product enhancements, write or fax to ``Product Manger, product name' at address above. In Europe: Adobe Systems BV, Europlaza, Hoogoorddreef 51a, 1101 BE Amsterdam Z-O, NETHERLANDS. TEL +31-20-65-11-200. FAX +31-20-65-11-300. In the eastern United States: Adobe Sys. Inc., 24 New England Executive Park, Burlington MA 01803. TEL +1-617-273-2120. FAX +1-617-273-2336. In Japan: Adobe Systems Japan, Swiss Bank House, 4-1-8 Toranomon, Minatoku, Tokyo 105 JAPAN. TEL +81-3-3437-8950. FAX +81-3-3437-8968. Subject: 6.2 What can Adobe do for me? Adobe is just one of many companies producing products for PostScript, but it does produce a lot of the best. Adobe offers two resources for software developers. 1. Membership in the Adobe Developers Association (ADA) ( $ 195/year) 2. PostScript Language Software Development Kit (SDK) ( $ 500, $ 250 for ADA) The Developer's Association is Adobe's way of knowing who has a serious interest in technical information. Membership includes monthly technical newsletter, phone technical support, discounts on software and hardware. Membership is $ 195/year for each individual. The PostScript Language Software Development Kits collect all Adobe's technical literature for a given platform into a single package. There are four versions, for the Mac, MS-DOS/Windows, NeXTStep, and X/Windows. Each SDK is $ 500 list, $ 250 for ADA members. A selection of technical documents is available from Adobe's file server, including the aforementioned EPS specification. For more information on this, send the one-word message ``help'' to ps-file-server@adobe.com. These documents are also available by mail; call the Developers Line and ask for the documents catalog. The ps-file-server contains some specs, tech notes, sample programs, plus a large collection of AFM files and PPD files. Send a message containing ``help'' to ps-file-server@adobe.com for more information. You can get these files for free with email. Subject: 7 Programming in PostScript Subject: 7.1 What is PostScript level 2? PostScript Level Two is a major upgrade to PostScript Level One. Starting from PostScript Level One as a basis, PostScript Level Two represents the confluence of many features: * Composite fonts -- fonts with the capability of supporting character sets with more than 256 characters. Such fonts are needed in the Asian marketplace, for example. * Patterns -- provide a device-independent way to describe patterns which tile an area. A pattern can be thought of as another kind of ``color'' in PostScript Level Two. * Forms -- to meet the demands of the forms market, forms describe static information which can be repeated many times on one page or printed on many separate pages, or both. * Color -- the previous ill-defined color models are now enhanced with the addition of CMYK color, support for color images, CIE device-independent color (if anybody can understand the damned thing). * Halftones -- new highly accurate halftone screening methods to meet the needs of high end typesetting equipment. * Display PostScript -- many enhancements and efficiency improvements to support the needs of screen rendering. Enhancements include: * efficient rectangle operators, * efficient font and text operators, * multiple contexts * shared memory models * hit detection A detailed description of PostScript 2 is available in the section on PostScript 2. Subject: 7.2 Should I learn level 2 PostScript? Yes, because Level Two will soon become the standard. Application developers using PostScript need to become aware of the new capabilities and how to take advantage of them. See the books section for info on what books teach level 2 PostScript. Subject: 7.3 Where can I find examples of PostScript code? Many other books on PostScript make example PostScript code available. (See the section on books.) All the examples in ``the blue book'' are available from the Adobe file server (See the section on Adobe.) See the question ``How can I browse through PostScript programs?'' in the section on utilities. Subject: 7.4 How do I get the physical size of a page? The initial clipping path gives you the size of the imagable area. Use ``clippath pathbbox'' to get these coordinates. If you must know the size of the device's imageable area, use the sequence ``gsave initclip clippath pathbbox grestore'', but this will prevent an enclosing application from using the clippath to achieve some special effects (such as multiple pages per page). Subject: 7.5 Why can't I do a pathforall after a charpath ? See the section on fonts, question ``Why are Adobe fonts hidden?''. Subject: 7.6 How do I center a string of text around a point? Level 1 PostScript has two operators that can extract information about the metrics of characters: ``stringwidth'' and ``charpath''. The ``stringwidth'' operator returns the advance width of its string operand. This is the distance the current point would be moved by a ``show'' operation on the same string. ``stringwidth'' returns two numbers on the stack, representing the x and y components of the advance width. Usually the y component is zero because most fonts are displayed along a horizontal line, moving the current point only in the x direction. Also note that the ``stringwidth'' operator includes any side bearings in its result. It usually does not give an exact measure of the area of the page that will be touched by its operand. If all that an application requires is horizontal centering of a long string of text, the result returned by ``stringwidth'' is sufficient. A common technique is x y moveto (string) dup stringwidth pop 2 div neg 0 rmoveto show (This code makes the assumption that the y component of advance width is irrelevant.) The ``charpath'' operator extracts the graphic shapes of its string operand and appends them to the current path in the graphic state. These shapes can then be processed by other PostScript operators. To get the actual size of the area touched by a character a simple approach is gsave newpath 0 0 moveto (X) true charpath flattenpath pathbbox grestore This code places four numbers on the stack, representing the coordinates of the lower left and upper right corners of the bounding box enclosing the character ``X'' rendered with the current point at (0,0). There are two things to be careful about when using the code shown above: 1. There are severe limits on the size of the string operand, related to the limit on the number of elements in a graphic path. The PostScript Language Reference Manual recommends taking ``charpath''s one character at a time. 2. If user space is rotated or skewed with respect to device space, the result from ``pathbbox'' may be larger than expected; ``pathbbox'' returns a rectangle oriented along the user space coordinate axes, which fully encloses a (possibly smaller) rectangle oriented along the coordinate axes of device space. If user space is rotated at an integer multiple of 90 degrees these two rectangles will be the same, otherwise the rectangle in user space will be larger. So, to center text vertically one must get the bounding boxes of all the characters in the string to be displayed, find the minimum and maximum y coordinate values, and use half the distance between them to displace the text vertically. If an application does this repeatedly, it would be wise to store the bounding boxes in an array indexed by character code, since ``charpath'' is a slow operation. Font metric information is available outside of a PostScript printer in font metrics files, available from Adobe. A program generating PostScript output can obtain metrics from these files rather than extracting the metrics in the printer. Subject: 7.7 How can I concatenate two strings together? %% string1 string2 append string % Function: Concatenates two strings together. /append { 2 copy length exch length add % find the length of the new. string dup % string1 string2 string string 4 2 roll % string string string1 string2 2 index 0 3 index % string string string1 string2 string 0 string1 putinterval % stuff the first string in. % string string string1 string2 exch length exch putinterval } bind def Subject: 8 Computer-specific PostScript This section describes PostScript information specific to a particular type of computer or operating system. Subject: 8.1 Sun Workstations What is Open Look? Open Look is Sun Microsystems ``Look and Feel'' Graphical User Interface. Open Look is the user-visible part of Open Windows. There is a lot of competition in industry over graphical user interface (GUI) systems. Some of the players are Sun with OpenLook and the Open Software Foundation (OSF) with MOTIF. What is Open Windows? Open Windows is Sun Microsystems window system for the Sun Workstation. Open Windows is based on the X/NeWS window server(s) and includes many tools and utilities. Don't confuse OpenWindows/OpenLook with Open Desktop from Santa Cruz Operation. Open Windows is the underpinnings of OpenLook. What is NeWS? NeWS is Sun Microsystems PostScript-based window system for the Sun Workstation. NeWS was a project within Sun (started around 1985) to create a window system to supplant SunView (a very successful kernel-based window system). NeWS is a client-server model window system (like X) but among many of NeWS novel features was the use of PostScript as the language to describe the appearance of objects on the screen. Because there are few ways to design a knee joint, NeWS has many features in common with Display PostScript, but NeWS predates Adobe Display PostScript and was neither connected with Adobe Display PostScript nor endorsed by Adobe. NeWS is not an Adobe product, nor is it a Sun/Adobe joint venture. NeWS had the potential to become a world-class window system had not a coalition of computer vendors ganged together to endorse the X window system from MIT, sending Sun into a frenzy to support both X and NeWS in the same window server. One respected engineer from DEC remarked they all feared Sun would ignore the industry X coalition and go on to make NeWS a standard. They were overjoyed when Sun reacted by taking on X and merging it with NeWS, causing additional work which made it harder for Sun to make progress with NeWS. Also it made X the de facto standard; whether or not this is a good thing depends on who you talk to. Sun management has signed a deal to adopt Display PostScript. Will they put NeWS aside then? And how does PostScript run on them? PostScript runs (mostly) on NeWS. Due to lack of support from Sun management, NeWS never made it as a fully-compliant PostScript interpreter. There were incompatibilities between the NeWS PostScript interpreter and ``official'' PostScript interpreters as defined by Adobe and the Apple LaserWriter family of printers, such that many PostScript files which would print fine on a LaserWriter would not render under NeWS. The most critical incompatibility was the lack of support for Adobe Type 1 fonts, Sun having gone with their own font format known as F3. Given the NeWS PostScript interpreter was not even PostScript Level One compliant, the chances of bringing NeWS to Level Two compliance was remote, lending further to NeWS decline. Subject: 8.2 IBM PC You can find nenscript for OS/2 1.x--2.0 and MSDOS on ftp-os2.nmsu.edu in pub/uploads/nensc113.zip. Subject: 8.3 Apple Macintosh For more details about printing with the Macintosh, read the comp.sys.mac.apps FAQ. How can I convert a PostScript file created with a UNIX program to the Mac? A way that is clumsy, but works, is this: 1. Display the UNIX-based PostScript file on screen 2. Use window dumping facility to get a bitmap file 3. Convert the above bitmap file to TIFF format and then export it to Adobe Illustrator on the Mac. The PostScript section of the FAQ for the Macintosh newsgroup comp.sys.mac.app (maintained by Elliotte Harold) answers the following questions: * How do I make a PostScript file? * How do I print a PostScript file? * Why won't my PostScript file print on my mainframe's printer? Full documentation of this process provided with a utility called macps. * Why are my PostScript files so big? Subject: 9 Encapsulated PostScript Subject: 9.1 What is Encapsulated PostScript? An Encapsulated PostScript file (EPSF) is a standard format for importing and exporting PostScript language files in all environments. It is usually a single page PostScript language program that describes an illustration. The purpose of the EPS file is to be included as an illustration in other PostScript language page descriptions. The EPS file can contain any combination of text, graphics, and images. An EPS file is the same as any other PostScript language page description, with some restrictions. EPS files can optionally contain a bitmapped image preview, so that systems that can't render PostScript directly can at least display a crude representation of what the graphic will look like. There are three preview formats: Mac (PICT), IBM (tiff), and a platform independent preview called EPSI. An EPS file must be a conforming file, that is, it must conform to the Adobe Document Structuring Conventions (DSC). At a minimum, it must include a header comment,%!PS-Adobe-3.0 EPSF-3.0, and a bounding box comment,%%BoundingBox: llx lly urx ury, that describes the bounds of the illustration. (The specification does not require the EPSF version, but many programs will reject a file that does not have it.) The EPS program must not use operators that initialize or permanently change the state of the machine in a manner that cannot be undone by the enclosing application's use of save and restore (eg. the operators starting with ``init'' like initgraphics). As a special case, the EPS program may use the showpage operator. The importing application is responsible for disabling the normal effects of showpage. The EPS program should make no environment-sensitive decisions (the importing application may be trying to attain some special effect, and the EPS program shouldn't screw this up), although it can use some device-dependent tricks to improve appearance such as a snap-to-pixel algorithm. The complete EPS specification is available from Adobe (see the section on Adobe). An optional component of an EPS file is a ``preview'' image of the file's content. The preview image is a bitmapped representation of the image which may be displayed by programs using the EPS file without having to actually interpret the PostScript code. The recommended form for a preview image is ``Interchange'' format and is described fully in the ``red book'', second edition. Interchange format represents the image as a series of hex strings placed in the EPS file as PostScript comments. The entire file remains an ASCII file. A variation of EPS embeds the preview image and PostScript text in a binary file which contains a header and the preview image in either a TIFF or MetaFile format. The header defines where in the file each section (EPS, TIFF, or MetaFile) starts and ends. On the Macintosh, the preview is stored as a PICT in the file's resource fork. What is EPSI? EPSI is EPS. EPSI is an all ASCII (no binary data or headers) version of EPS. EPSI provides for a hexadecimal encoded preview representation of the image that will be displayed or printed. Subject: 9.2 How do I convert PostScript to EPS? To convert from PostScript to EPS, one must guarantee that the PostScript file meets the above requirements. If the actual program conforms to the programming requirements, then one can simply add the required comments at the top of the file saying that the file is EPS and giving its BoundingBox dimensions. Optional comments include font usage (%%DocumentFonts: or%% DocumentNeededResources: font), EPSI preview comments (%% Begin(End)Preview:) extensions (%%Extensions:) and language level (%%LanguageLevel:). There are some operators that should not be used within an EPS file: banddevice cleardictstack copypage erasepage exitserver framedevice grestoreall initclip initgraphics initmatrix quit renderbands setglobal setpagedevice setshared startjob These also include operators from statusdict and userdict operators like legal, letter, a4, b5, etc. There are some operators that should be carefully used: nulldevice setgstate sethalftone setmatrix setscreen settransfer undefinefont To convert a PostScript file to EPS format, you must edit the file using a text editor or word processor to add lines that will define the file as an EPS-format file. 1. Using your normal method of printing, print the PostScript file to a PostScript printer. You can choose to view it on the screen instead, but keep in mind that all the below distance measurements assume that you are printing on a normal-sized piece of paper. NOTE: If the PostScript image does not get displayed properly, it probably will not work either once you have converted it to EPS format. Correct the PostScript program so that it works before you convert it to EPS format. 2. Use a tool (see below) to find the bounding box, which shows how much space the PostScript image occupies when printed. You specify the dimensions of the bounding box when you convert the PostScript file to EPS format. 3. If you don't have a bounding box tool, you can just use a ruler and draw one on your printout. With two horizontal lines and two vertical lines, draw a box around the image that includes the entire image while minimizing white space. This box represents your bounding box. You may want to leave a small amount of white space around the image as a precautionary measure against minor printing problems, such as paper stretching and paper skewing. 4. Measure distance ``a'' from the lower-left corner of the image to the left edge of the paper. 5. Write the measurement in points. If your ruler does not show points, calculate the total number of points: 1 inch = 72 points, 1 cm = 28.3 points, and 1 pica = 12 points. Designate this measurement as ``measurement a.'' 6. Measure distance ``b'' from the lower-left corner of the image to the bottom edge of the paper. Designate this measurement in points as ``measurement b.'' 7. Measure distance ``c'' from the upper-right corner of the image to the left edge of the paper. Designate this measurement in points as ``measurement c.'' 8. Measure distance ``d' from the upper-right corner of the image to the bottom edge of the paper. Designate this measurement in points as ``measurement d.'' 9. Using any text editor, open the PostScript file for editing. You'll see several lines of text. These lines are the PostScript description of the image. The lines at the top of the file are the header. 10. Add these lines to, or modify existing lines in, the header (the first group of lines in any PostScript file): %!Adobe-2.0 EPSF %%Creator: name %%CreationDate: date %%Title: filename %%BoundingBox: a b c d Note: Make sure that the first line in the file is `` Also, do not separate the header lines with a blank line space. The first blank line that PostScript encounters tells it that the the next line begins the body of the program. For ``name,'' type your name or initials. For ``date,'' type today's date using any format (for example, MM-DD-YY, MM/DD/YY, July 5, 1987, and so on). For ``filename,'' type the name of the PostScript file. After ``BoundingBox: ,'' type the measurements you took in steps 3, 4, 5, and 6, separating each with a space: ``a'' is the measurement from Step 3, ``b'' is the measurement from Step 4, ``c'' is the measurement from Step 5, and ``d'' is the measurement from Step 6. 11. Save the file in text-only format. If you are interested in learning how to further edit your PostScript files, these books are available at most bookstores: Understanding PostScript Programming and the green book. Encapsulated PostScript is discussed in Appendix C of the old red book. The new red book has a lot of information about Encapsulated PostScript. There will be a technical note available from Adobe called 'Guidelines for Specific Operators' that will talk about why some operators are prohibited and how to use the others. Subject: 9.3 How do I get the bounding box of a PostScript picture? Use bbfig or epsinfo.ps. Or if you would rather construct the bounding box by hand, use Ghostview, which has a continuous readout of the mouse cursor in the default user coordinate system. You simply place the mouse in the corners of the figure and read off the coordinates. Subject: 10 About The Comp.Lang.PostScript FAQ (and Usenet Guide to PostScript) Subject: 10.1 The PostScript FAQ: What is it? The PostScript FAQ is a set of answers to frequently asked questions (FAQs) that have appeared on the Usenet newsgroup comp.lang.postscript. It is broken into many useful sections. The Usenet Guide to PostScript is a larger set of help and answers to PostScript questions, plus a tutorial for new users. It is still in the process of being created. There is one file ``Exactly What Does a Transformation Matrix Do?'', that is definitely not part of the FAQ. Please send more! I need help writing and revising answers for common questions relating to PostScript. Almost all of the information in the documents has been written by kind volunteers. The answers will be published in either or both documents. A very long answer in the Usenet Guide may be summarized, referred to briefly, or not mentioned at all in the FAQ. Subject: 10.2 How to get the FAQ files The FAQ is available by anonymous ftp to wilma.cs.brown.edu:pub/comp.lang.postscript/ You can get it formatted in plain text ASCII, LaTeX, or PostScript. I would be happy to email a copy of the FAQ in any format to you if you do not have FTP. Subject: 10.3 How to write a FAQ answer I greatly appreciate your time and effort to help improve the quality of the FAQ. Thank you for being willing to contribute! * Please check to see if the topic is already in an FAQ. Perhaps you really mean to submit a revision to an existing section. * Start with a clear statement about what problem you are solving. * Write for novice users, in ``tutorial format'', even if the answer is meant for experienced programmers. * Be specific when you make references. * Be complete, and take the time to look over your draft and revise. * Answers should not be too wordy, unless you intend to write a long answer for the Usenet Guide and have a shorter summary or a pointer to the description placed in the FAQ. If you want to write the summary yourself, thanks! * Obviously, I cannot accept copyrighted material without permission. Don't write the FAQ by paraphrasing from a copyrighted book! Subject: 10.4 The FAQ can contain LaTeX and PostScript inserts The FAQ is actually written with LaTeX, so feel free to submit with that text formatting language. There is a PostScript version of the FAQ also, so feel free to send along PostScript pictures to include. Subject: 10.5 Revising the FAQ Suggestions and comments are welcomed. My favorite way of receiving a change suggestion is if you make a copy of the FAQ, edit the copy, and mail me the modification, or a context diff (include the version number). Subject: 10.6 How to submit new information If you know something that you think is worthwhile to be put in a FAQ, definitely send it to me! Don't hold back if your information is very specific. If there's too much information to post I will archive it at an ftp site and place a pointer to it in the FAQ. Subject: 10.7 How to add a program description to the FAQ index If the program is original, please send it to me, or tell me where I can get it. Please put your name and email address at the top of each file. Your program will be doubly useful if you clean up the program so that other people can use it as an example to learn. If the program was written by someone else, please send me just the title, description, and where to get it. I may already have it. For programs the FAQ needs to know: * What is the name of the program? * What does it claim to do, and does it do it well? Is it worth using? * Where is it available? What ftp sites can I get it from? * How much does it cost? Is it free? * What kinds of computers does it run on? * Who is the author and does the author give an email address? * Does it handle PostScript 2? If the program is a PostScript interpreter, then the FAQ also needs to know: * Does it let you go backwards one page? * Does it display the number of pages in the document? * Does it let you print PostScript to a non-PostScript printer? * What formats can it convert to? Subject: 10.8 How to add a book description to the FAQ For books the FAQ needs to know: * What is the name of the book or document? * What does it claim to do, and does it do it well? Is it worth using? * Can I get it on-line? * Who wrote it? Does the author give an email address? * Who is the publisher, and what is the copyright date? * Does the publisher list an address and phone number or fax number? * What is the ISBN number of the book? * What is the library call number of the book? * How much does the book cost? * Does it cover PostScript 2? * Are coding examples from the book available by email or anonymous ftp? * Do the authors sell the coding examples on a diskette? Subject: 10.9 Questions that need answers 1. Where are ftp sites that have PostScript freeware? 2. What vendors sell fonts for PostScript printers? Where are the free ftp sites for them? 3. Are there any free encapsulated PostScript converters? 4. What is the charter for comp.lang.postscript? 5. How do I make a downloaded font (ie: PFA) persistent? 6. What questions should the FAQ have? 7. What book information is wrong or missing in the FAQ? 8. What program information is wrong or missing in the FAQ? 9. What ftp site have good examples of PostScript code? Table of Contents 11 About PostScript 2 11.1 What printers run PostScript 2? 11.2 Introduction 11.3 What is PostScript Level 2? 11.4 What are the features of PostScript Level 2? 11.5 What are the color extensions to the PostScript language? 11.6 Why would you want the CMYK color extensions in a black and 11.7 What are the composite font extensions to the PostScript 11.8 Why would you want the composite font extensions in a roman 11.9 What are the Display PostScript Extensions to the PostScript 11.10 Why would you want the Display PostScript extensions in a 11.11 Can you tell me more about the rest of the PostScript Level 2 11.12 Filters 11.13 Binary Encoding 11.14 Improved underlying implementation 11.15 Improved memory management system 11.16 Optimized graphics operators 11.17 Optimized text operators 11.18 Forms 11.19 Patterns 11.20 Images 11.21 Composite Fonts 11.22 New Color Spaces 11.23 New screening/halftoning technology 11.24 Improved printer support features 11.25 Interpreter parameters 11.26 Resources 11.27 Dictionaries 11.28 What's the feedback from Adobe's OEMs on PostScript Level 2? 11.29 How much ROM/RAM will it take for a Level 2 printer? 11.30 When did Level 2 products come available? 11.31 What about existing PostScript printers? Are they obsolete? 11.32 Are Level 1 and Level 2 implementations compatible? 11.33 When will the new red book be available? 11.34 How is Adobe positioning PostScript Level 2? 11 About PostScript 2 11.1 What printers run PostScript 2? * Apple LaserWriter IIf * Apple LaserWriter IIg * Apple Personal LaserWriter NTR Apple sells an upgrade to the IINTX to turn it into a IIf/IIG for instance. * Compaq PAGEMARQ 20 * Compaq PAGEMARQ 15 * Data Products LZR 960 * Data Products LZR 1560 * Hewlett-Packhard PostScript CartridgePlus, which works with the HP Laserjet III, IIID, and IIIP. * NEC SilentWriter2, model 95 * Tektronix Phaser III PXi * Tektronix Phaser II PXi * Tektronix Phaser II PXe * Tektronix Phaser IISD * Texas Instruments microLaser Turbo * Texas Instruments microLaser XL Turbo This rest of file contains a description of PostScript 2 written by Carl Orthlieb from Adobe. 11.2 Introduction PostScript Level 2, the first major new release of PostScript software since its introduction, is a unification and enhancement of the PostScript language based on the needs voiced by users of PostScript printers and Display PostScript(R) workstations, Independent Software Vendors (ISVs), and Original Equipment Manufacturers (OEMs). PostScript Level 2 contains a number of performance enhancements, is easier for software developers to use, and contains important new functionality such as device-independent color, forms handling and patterns support. 11.3 What is PostScript Level 2? First, let's look at the current state of the PostScript language. The baseline of the language is defined by the PostScript Language Reference Manual, also known as the "red book." The red book defines the basic PostScript language imaging model functionality for line art, sampled images, text, and the RGB color model. Since its introduction in 1985, the PostScript language has been considerably extended for greater programming power, efficiency, and flexibility. Typically, these language extensions have been designed to adapt the PostScript language to new imaging technologies or system environments. While these extensions have introduced new functionality and flexibility to the language, the basic imaging model remains unchanged. The principal language extensions are: Color: The color extensions provide a cyan-magenta-yellow-black (CMYK) color model for specifying colors and a colorimage operator for painting sampled images. They also include additional rendering controls for color output devices. Composite fonts: The composite font extensions enhance the basic font facility to support character sets that are very large or have complex requirements for encoding or character positioning. Display PostScript: The Display PostScript system enables workstation applications to use the PostScript language and imaging model for managing the appearance of the display. Some of the extensions are specialized to interactive display applications, such as concurrent execution and support for windowing systems. Other extensions are more general and are intended to improve performance or programming convenience. When Adobe decided to add additional functionality to the PostScript language, we did not want to add the functionality in a piecemeal fashion and have it exist in some devices but not others. This makes life difficult for independent software vendors (ISVs) who write PostScript language programs. PostScript Level 2 integrates the original PostScript language, all previous language extensions, and new language features into the core PostScript language imaging model. PostScript Level 2 ensures application developers consistent functionality across all Level 2 devices. When an application images to a Level 2 device, it can be assured that a wide range of features will exist on that device and that these features can be exploited to their fullest for increased performance and functionality. 11.4 What are the features of PostScript Level 2? PostScript Level 2 consolidates all of the current language extensions into one unified language and adds many new features. It is also upward compatible with the current generation of PostScript devices. Here is a brief list of what comprises PostScript Level 2: * Existing PostScript language * Color extensions * Composite font extensions * Display PostScript extensions * Improved memory management * CIE-based device-independent color * Improved printer hardware features support * Data and image compression and decompression * Optimized graphics and text operators from the * Display PostScript system * New halftoning algorithms * Forms support * Patterns support * Binary language encodings * ATM font rendering technology 11.5 What are the color extensions to the PostScript language? The color extensions were added to the language in 1988 to provide more complete color functionality. With the original PostScript language, color could be specified using the red-green-blue (RGB) and hue-saturation-brightness (HSB) color models. The color extensions include cyan-magenta-yellow-black (CMYK) color model, black generation and undercolor removal functions, screen and transfer functions for four separate color components, and a colorimage operator for rendering color sampled images. The color extensions are currently found in PostScript color printers from Canon, QMS, Oce, and NEC as well as all implementations of the Display PostScript system. 11.6 Why would you want the CMYK color extensions in a black and white printer? In a nut-shell, compatibility between black-and-white and color Level 2 devices. Today, ISVs must handle PostScript color printers differently. For example, current monochrome laser printers does not contain the CMYK color extensions, and as a result PostScript language programs must emulate this functionality, which results in slower performance. All Level 2 implementations will include the CMYK color extensions as standard. 11.7 What are the composite font extensions to the PostScript language? The composite font technology is a general solution that extends the basic PostScript language font mechanism to enable the encoding of very large character sets and handle non-horizontal writing modes. A Type 1 PostScript font has room for encoding only 256 distinct characters. A typical Japanese font has over 7,000 Kanji, katakana and hiragana characters. The composite font technology allows you to create one ``composite'' font that is made up from any number of ``base'' fonts. In addition, the composite font technology allows you to include two sets of metrics (character spacing details) in the font: one for a horizontal-writing mode, and one for a vertical-writing mode. 11.8 Why would you want the composite font extensions in a roman printer? This technology is currently implemented only in Japanese language PostScript devices, but the composite font technology is a general solution that applies to any language. It allows for the creation of one composite font that combines two or more fonts. For example, you may wish to combine a text font (such as Times-Roman) with a special font (such as Zapf-Dingbats) and have all characters at your disposal within a single font. 11.9 What are the Display PostScript Extensions to the PostScript language? The Display PostScript extensions address the needs of using the PostScript language imaging model in a display environment. It includes extensions to deal specifically with displays and windowing systems as well as many optimized operators to increase performance which is critical in an interactive display environment. 11.10 Why would you want the Display PostScript extensions in a printer? Most of the functionality in PostScript Level 2 that comes from the Display PostScript extensions result in improved performance. This includes clipping, rectangle operators, and binary language encoding to name a few. Each of the new Level 2 features that come from the Display PostScript extensions are detailed later in this document. Another obvious reason is for compatibility between Display PostScript applications and PostScript Level 2 printers. 11.11 Can you tell me more about the rest of the PostScript Level 2 features? Sure. Here a brief overview of the important features and benefits of PostScript Level 2: 11.12 Filters * A filter transforms data as it is being read from or written to a file. The language supports filters for ASCII encoding of binary data, compression and decompression, and embedded subfiles. Properly used, these filters reduce the storage and transmission cost of page descriptions, especially ones containing sampled images. Benefits: Reduced storage requirements, greater performance. * ASCII encoding of binary data: ASCII/85 (represent binary data in ASCII format with only a 125 % expansion of data), and ASCII/HEX (current method of representing binary data in ASCII format but with a 200 % expansion of data). Benefits: Compact representation of binary data in a portable ASCII representation. * Compression and decompression filters: CCITT Group 3 & 4 (monochrome images), run-length encoding (monochrome and grayscale images), LZW ( 2:1 compression of text files), DCT (20-200:1 compression of color images using the proposed JPEG standard). Benefits: Improved performance due to reduced transmission times. PostScript files on disk can also be made much smaller, saving disk space. 11.13 Binary Encoding In addition to the standard ASCII encoding, the language syntax includes two binary-encoded representations. These binary encodings improve efficiency of generation, representation, and interpretation. However, they are less portable than the ASCII encoding and are suitable for use only in controlled environments. Benefits: performance,z compactness. 11.14 Improved underlying implementation * Improved font disk cache. We have improved the backup of the font cache on printers with a hard disk. Font access methods for reading the font back into RAM are more efficient. Also, the management of the disk is improved, so it does not become fragmented. Benefits: Performance, enhanced functionality. * ATM font rendering technology. Benefits: Improved performance (4-5 times faster in raw character building speed) and improved quality (most evident at small point sizes and low resolutions). 11.15 Improved memory management system * One pool of memory available for all resource needs (page image, font cache, path storage, downloadable fonts, etc.). Memory allocated dynamically to meet needs. In general, memory is more efficiently shared among different uses and arbitrary memory restrictions have been eliminated. Benefits: Eliminates arbitrary memory restrictions for imaging of more complex graphics. * Opportunistic memory management scheme. In the current system, the PostScript language program must manage memory on a per page basis. New memory management operators allow more flexibility for programs to explicitly release unused memory resources by removing individual entries from dictionaries and removing font definitions in an order unrelated to the order in which they were created. Benefits: More efficient use of available memory. * Automatic memory reclamation. VM is reclaimed automatically for composite objects that are no longer accessible, such as strings used by the show operator. A ``garbage collector'' will automatically reclaim other unused memory. Benefits: More efficient use of available memory. 11.16 Optimized graphics operators * Rectangle operators. New operators for filling, clipping and stroking rectangles; all highly optimized. For example, rectfill is 3 times faster than an equivalent moveto, lineto, lineto, lineto, closepath, fill. Benefits: performance and convenience. * Graphics state objects provide a fast way to switch between graphics states, which define the current line weight, color, font, etc. In existing printers, graphics states are stored on a stack, so accessing an arbitrary graphics state is somewhat cumbersome. With graphics state objects, the graphics state can be associated with a name, and retrieved by simply requesting the name. Benefits: Performance, convenience. * Halftone specification. New halftone dictionaries provide a more precise way of specifying the halftone dots, and makes switching between halftone screens faster. (The spot function is not reinterpreted.) Benefits: Performance, convenience, enhanced functionality. * User paths are self-contained procedures that consists entirely of path construction operators and their coordinate operands. User path operators perform path construction and painting as a single operation; this is both convenient and efficient. There is a user path cache to optimize interpretation of user paths that are invoked repeatedly. Benefits: Performance, convenience. * Stroke adjustment. For very thin lines, there is a trade-off between perfect positioning and consistent line width. Depending on the placement of such a line, it could end up being rendered as either 1 or 2 pixels wide, which is a noticeable difference. To account for this, PostScript language programs often include logic to slightly alter the coordinates of lines for consistent rendering. With automatic stroke adjustment the interpreter performs this adjustment to ensure consistent widths. Doing it in the interpreter rather than in the PostScript language program is 20 - 30 % faster. Benefits: Performance, convenience, improved quality. 11.17 Optimized text operators * The xyshow operator provides a more natural way for applications to deal with individual character positioning. Allows simultaneous track kerning, pair kerning, and justification. Benefits: Performance, convenience. * The selectfont operator optimizes switching between fonts. It does the work of 3 Level 1 operators: findfont, scalefont, and setfont and has been optimized by using a caching mechanism. Benefits: Performance, convenience. 11.18 Forms * A form is a self-contained description of any arbitrary graphics, text, and sampled images that are to be painted multiple times on each of several pages or several times at different locations on a single page. * With the new forms feature, you can define a base form whose representation stays cached between pages, so only information that changes between forms will need to be interpreted for each page. The representation used to cache the form may vary from device to device depending on the available resources, such as memory and/or hard disk space. In some cases, the actual rasterized form will be saved, in other cases, an intermediate representation (such as a display list) may be saved. Benefits: End-users will benefit by improved performance. * This makes forms processing faster and provide a natural framework for ISVs implementing a forms functionality in their application. Benefits: Convenience for ISVs. * Besides the traditional concept of ``forms,'' some other examples of forms include: Letterhead, stationary, overhead presentation backgrounds, repetitive symbols in a CAD drawing such as screws (mechanical drawing) or windows (architectural drawing), complex background blends in 35mm slides. Benefits: Enhanced functionality and application of PostScript printers in a variety of different environments. 11.19 Patterns * The new pattern color space provides the ability to establish a pattern as the current color. Subsequent use of operators such as fill, stroke, and show apply ``paint'' that is produced by replicating (or tiling) a small graphical figure called a pattern cell at fixed intervals in x and y to cover the areas to be painted. The appearance of a pattern cell is defined by a PostScript language procedure, which can include any arbitrary graphics, text, and sampled images. The shape of the pattern cell need not be rectangular, and the spacing of tiles can differ from the size of the pattern cell. Benefits: Enhanced functionality, performance, convenience. * For efficiency, the representation of the pattern cell may be cached. When cached, the execution of the procedure that defines the pattern need be done only once for the current pattern. The pattern cache is similar to the font cache. Benefits: Performance. * Multiple colors can be specified in the pattern or the pattern can be used as a mask to paint a color defined in some other color space. Benefits: Enhanced functionality * For display environments, this feature will allow patterns to be represented in a resolution independent manner. Until now, patterns have typically been represented by arrangements of pixels. This resolution-dependent representation does not work well when trying to image the pattern at a variety of different resolutions. 11.20 Images There are several enhancements to the facilities for painting sampled images: use of any color space, 12-bit component values, direct use of files as data sources, and additional decoding and rendering options. Benefits: Convenience, performance, quality. 11.21 Composite Fonts * Provides the basic machinery for non-Roman character sets. Enables the encoding of very large character sets and non-horizontal writing modes. Benefits: Enhanced functionality. * Provides a page description language for international business. Composite font technology makes printers more international. The same font technology can be used worldwide, and will provide support for companies that must work in today's international business environment. Benefits: Enhanced functionality. * Advantages not limited to foreign languages - also useful for strictly Roman printers: allows the creation of a single composite font that combines two or more fonts. For example, you may wish to combine a textual font (such as Times-Roman) with a graphical font (such as Zapf-Dingbats), and have all characters at their disposal within a single font. Other uses of composite fonts: IBM extended character set, and expert sets (such as Adobe Garamond). Benefits: Enhanced functionality and increased performance by minimizing switching between fonts. 11.22 New Color Spaces * CMYK color model and support for color images. Enhanced functionality. This will encourage more ISVs to use the color operators, because the operators will be widely available (The printer itself may not be able to print in color, but the PostScript language program won't generate errors when the operators for CMYK color are used.) * PostScript Level 2 supports several device-independent color spaces based on the CIE 1931 (XYZ)-space. CIE-based color specification enables a page description to specify color in a way that is related to human visual perception. The goal of the CIE standard is that a given CIE-based color specification should produce consistent results on different color output devices, independent of variations in marking technology, ink colorants, or screen phosphors. True device-independent color specification. Improved color matching between devices. * PostScript Level 2 supports three classes of color spaces: device independent, special, and device dependent. The following device independent color spaces are standard: The CIEBasedABC color space is defined in terms of a two-stage, non- linear transformation of the CIE 1931 (XYZ)-space. The formulation of the CIEBasedABC color space models a simple zone theory of color vision, consisting of a non-linear trichromatic first stage combined with a non-linear opponent color second stage. This formulation allows colors to be digitized with minimum loss of fidelity; this is important in sample images. Special cases of CIEBasedABC include a variety of interesting and useful color spaces, such as the CIE 1931 (XYZ)-space, a class of calibrated RGB spaces, a class of opponent color spaces such as the CIE 1976 (L*a*b*)-space and the NTSC, SECAM, and PAL television spaces. The CIEBased A color space is a one-dimensional and usually achromatic analog of CIEBasedABC. The following special color spaces are standard: * The Pattern color space enables painting with a ``color'' defined as a pattern, a graphical figure used repeatedly to cover the areas that are to be painted. See the discussion of patterns for more information. * The Indexed color space provides a way to map from small integers to arbitrary colors in a different color space such as a device independent color space. * The Separation color space provides control over either the production of a color separation or the application of a device colorant, depending on the nature and configuration of the device. The following device dependent color spaces are standard: * The DeviceGray color space is equivalent to the existing PostScript language's gray color model. * The DeviceRGB color space is equivalent to the existing PostScript language's red-green-blue (RGB) color model. * The DeviceCMYK color space is equivalent to the existing PostScript language's cyan-magenta-yellow-black (CMYK) color model. 11.23 New screening/halftoning technology * Improved algorithms for determining the angles and frequencies used for halftone screens. The improvements fall into two primary categories: general improvements, and improvements specific to color separations. * General improvements: (1) The new algorithms yield a 10 % improvement in the speed of the setscreen and image operators; (2) Earlier version of PostScript software could produce halftone screens only for certain angle and frequency combinations. Enough of these combinations were available so that any requested screen could be fairly well approximated by one of the available angle and frequency combinations. In contrast, the improved halftoning algorithms can provide as much as a ten-fold increase in the number of angle-frequency combinations that are available, depending on the device resolution and the available memory. Benefits: Increased performance and higher quality halftone screens. * Improvements specific to color separations: An additional feature is available that enables PostScript software to generate extremely accurate screen angles and frequencies. The screens produced by this method can achieve an angular accuracy of within 05 degrees or better, depending on such parameters as exact screen angle requested, device resolution, and memory available for use by the algorithm. Benefits: Extremely high-quality color separations that approach the quality that previously was available only from high-end, color electronic pre-press systems. 11.24 Improved printer support features * Page device setup provides a device independent framework for specifying the requirements of a page description and for controlling both standard features, such as the number of copies, and optional features, such as duplex printing, paper trays, paper sizes, and other peripheral features. * Applications developers will be able to write a single driver for a variety of different PostScript printers. The same code can be used to address printer specific features whether the features exist in the printer or not. If the feature is not in the printer, the application can decide how to best respond to the lack of the feature. Benefits: Enhanced functionality. ISVs benefit by having a more uniform method for accessing printer specific features. End users benefit by having software that will take advantage of their printer's features. 11.25 Interpreter parameters Administrative operations, such as system configuration and changing input-output device parameters, are now organized in a more systematic way. Allocation of memory and other resources for specific purposes is under software control. For example, there are parameters controlling the maximum amount of memory to be used for VM, font cache, pattern cache, and halftone screens. Benefits: Flexibility. 11.26 Resources * A resource is a collection of named objects that either reside in VM or can be located and brought into VM on demand. There are separate categories of resources with independent name spaces - for example, fonts and forms are distinct resource categories. * The language includes convenient facilities for locating and managing resources. 11.27 Dictionaries Many Level 2 operators expect a dictionary operand that contains key-value pairs specifying parameters to the operator. Language features controlled in this way include halftones, images, forms, patterns, and device setup. This organization allows for optional parameters and future extensibility. For convenience in using such operators, the PostScript language syntax includes new tokens, << and >>, to construct a dictionary containing the bracketed key-value pairs. Benefits: Convenience, extensibility. 11.28 What's the feedback from Adobe's OEMs on PostScript Level 2? The feedback has been overwhelmingly positive. We have always believed that we are taking our OEMs, ISVs and end users best interests into account in moving forward with the PostScript language. The feedback we have received so far confirms that we are doing the right thing on all fronts. 11.29 How much ROM/RAM will it take for a Level 2 printer? As is true with our current implementations, RAM/ROM requirements will vary from one device to the next depending on the specific capabilities of each device. However, our estimates put the code size at approximately 1.5 Mb of ROM (for CISC processors), and 1.5 Mb of RAM, minimum. 11.30 When did Level 2 products come available? The first Level 2 products were available in early 1991. 11.31 What about existing PostScript printers? Are they obsolete? The current generation of PostScript printers (which you could think of as PostScript Level 1) will not become obsolete because of Level 2 products. Think of Level 1 and Level 2 printers as a family of products, each having its own set of features to suit the needs of a particular customer. While we will continue to support and build Level 1 products (based on our OEM's demands) we think that over the next 12-18 months most of our OEMs will begin providing PostScript Level 2 products. 11.32 Are Level 1 and Level 2 implementations compatible? All existing programs that run on today's PostScript printers will run on a Level 2 device. That is, PostScript Level 2 is upward compatible with the existing installed base of printers and print drivers. However, it is not 100 % backward compatible. A file written specifically to take advantage of some Level 2 features will not run on a Level 1 printer because some functionality cannot be emulated. Most Level 2 features can be emulated on a Level 1 printer and an intelligent driver can conditionally use Level 2 features when available, and fall back on Level 1 operators when not. The new red book will include an appendix that will help ISVs deal specifically with compatibility issues. 11.33 When will the new red book be available? A new version of the red book, called the PostScript Language Reference Manual, Second Edition, will be published by Addison- Wesley in December 1990. 11.34 How is Adobe positioning PostScript Level 2? Adobe is positioning PostScript Level 2 as an integral part of a total system solution for printing and display environments. PostScript Level 2 software provides the foundation for Adobe's OEMs to implement an entire spectrum of products from low-cost desktop laser printers for office-automation to high-resolution imagesetters for producing color separations. Let's put PostScript Level 2 in perspective with respect to the overall printing solution. The effectiveness and performance of any particular printing solution is affected by four main elements: * Driver: Each major system software environment (Macintosh, Windows, OS/2 Presentation Manager, NeXT) has a built-in PostScript language driver. These system level drivers ensure that all applications running in the environment can output to PostScript printers. These drivers do not always produce the most efficient PostScript language programs, and may not support the wide variety of features available in the language or specific hardware features in a PostScript printer. * Language: The PostScript language as defined in the PostScript Language Reference Manual (the ``red book'') is the standard today. * Communications: AppleTalk, parallel, and serial communications are the most commonly used interfaces with PostScript printers today. * Controller: Today, most Adobe PostScript printers are based on a variety of controllers: Scout (68000), Atlas (68020), and Atlas Plus (68030). In addition, there are a number of custom controller solutions offered by our OEMs. Total system throughput is a function of all four elements. An efficient driver can produce PostScript page descriptions that print much faster; speed increases of 2-3x over an inefficient driver are not uncommon. Communications bottlenecks can account for a majority of the time it takes to print a page; a very large scanned image can take minutes to transmit to the printer, even using AppleTalk. And of course, the speed of the controller itself has a direct impact on the time it can take to print a page. However, the limiting factor PostScript Level 2 is one component of a total systems solution being assembled by Adobe: * Adobe is developing drivers for the Macintosh, Windows 3.0, and OS/2 Presentation Manager environments. These drivers will take full advantage of the features and performance enhancements in PostScript Level 2 printers as well as existing PostScript printers. * PostScript Level 2 extends the PostScript language with new operators to improve performance and provide additional functionality to address the need of end users and ISVs. * PostScript Level 2 includes a variety of file compression techniques that can be used to reduce the amount of information sent (and hence the time to do so) to the PostScript printer. * Adobe is developing new controllers based on the latest RISC technology which are up to 22 times faster than current controllers. In addition, these controllers provide our OEMs the potential for providing direct SCSI input and Ethernet connections for increased throughput. (C) 1990 Adobe Systems Incorporated. All rights reserved. PostScript, Display PostScript, and Adobe are trademarks of Adobe Systems Incorporated registered in the U.S. All other product names are trademarks or registered trademarks of their respective holders. .