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Encyclopedia > PostScript
PostScript
Paradigm: multi-paradigm: stack-based, procedural
Appeared in: 1982
Designed by: John Warnock & Chuck Geschke
Developer: Adobe Systems
Typing discipline: dynamic, strong
Major implementations: Adobe PostScript, TrueImage, Ghostscript
Influenced by: Forth
Influenced: PDF
PostScript
File extension: .ps
MIME type: application/postscript
Uniform Type Identifier: com.adobe.postscript
Magic: %!
Developed by: Adobe Systems
Type of format: printing file format
Extended to: Encapsulated PostScript

PostScript (PS) is a page description language and programming language used primarily in the electronic and desktop publishing areas. PostScript (PS) is a page description language and programming language used primarily in the electronic and desktop publishing areas. ... Image File history File links PostScript_3. ... A programming paradigm is a paradigmatic style of programming (compare with a methodology, which is a paradigmatic style of doing software engineering). ... This does not cite any references or sources. ... A stack-oriented programming language is one that relies on a stack machine model for passing parameters. ... This does not adequately cite its references or sources. ... Year 1982 (MCMLXXXII) was a common year starting on Friday (link displays the 1982 Gregorian calendar). ... John Warnock John Warnock (b. ... Charles M. Chuck Geschke (born September 11, 1939) is best known as the co-founder with John Warnock of Adobe Systems Inc. ... A software developer is a person who is concerned with one or more facets of the software development process, a somewhat broader scope of computer programming or a specialty of project managing. ... Adobe Systems (pronounced a-DOE-bee IPA: ) (NASDAQ: ADBE) (LSE: ABS) is an American computer software company headquartered in San Jose, California, USA. Adobe was founded in December 1982[1] by John Warnock and Charles Geschke, who established the company after leaving Xerox PARC in order to develop and sell... In computer science, a type system defines how a programming language classifies values and expressions into types, how it can manipulate those types and how they interact. ... Look up Implementation in Wiktionary, the free dictionary. ... PostScript (PS) is a page description language and programming language used primarily in the electronic and desktop publishing areas. ... TrueImage is a PostScript-compatible interpreter (clone) originally developed by Cal Bauer and Bauer Enterprises and sold to Microsoft in 1989. ... Ghostscript is a suite of software based on an interpreter for Adobe Systems PostScript and Portable Document Format (PDF) page description languages. ... Forth is a programming language and programming environment, initially developed by Charles H. Moore at the US National Radio Astronomy Observatory in the early 1970s. ... PDF is an abbreviation with several meanings: Portable Document Format Post-doctoral fellowship Probability density function There also is an electronic design automation company named PDF Solutions. ... A filename extension is a suffix to the name of a computer file applied to show its format. ... Multipurpose Internet Mail Extensions (MIME) is an Internet Standard that extends the format of e-mail to support: text in character sets other than US-ASCII; non-text attachments; multi-part message bodies; and header information in non-ASCII character sets. ... A Uniform Type Identifier (UTI) is a string that uniquely identifies the type of a class of items. ... In computer programming, a magic number is a constant used to identify the file or data type employed. ... Adobe Systems (pronounced a-DOE-bee IPA: ) (NASDAQ: ADBE) (LSE: ABS) is an American computer software company headquartered in San Jose, California, USA. Adobe was founded in December 1982[1] by John Warnock and Charles Geschke, who established the company after leaving Xerox PARC in order to develop and sell... Encapsulated PostScript, or EPS, is a graphics file format. ... A page description language (PDL) is a language that describes the contents of a printed page in a higher level than an actual output bitmap. ... A programming language is an artificial language that can be used to control the behavior of a machine, particularly a computer. ... Adobe InDesign CS2, one of many popular desktop publishing applications. ...

Contents

History

The concepts of the PostScript language were seeded in 1976 when John Warnock was working at Evans & Sutherland, a famous computer graphics company. At that time John Warnock was developing an interpreter for a large three-dimensional graphics database of New York harbor. Warnock conceived the Design System language to process the graphics, very similar to the Forth programming language. Year 1976 Pick up sticks(MCMLXXVI) was a leap year starting on Thursday (link will display full calendar) of the Gregorian calendar. ... John Warnock John Warnock (b. ... Evans & Sutherland is a computer firm involved in the computer graphics field. ... For the journal by ACM SIGGRAPH, see Computer Graphics (Publication). ... “NY” redirects here. ... Forth is a programming language and programming environment, initially developed by Charles H. Moore at the US National Radio Astronomy Observatory in the early 1970s. ...


Concurrently, researchers at Xerox PARC had developed the first laser printer and had recognized the need for a standard means of defining page images. In 1975-76 a team led by Bob Sproull developed the Press format, which was eventually used in the Xerox Star system to drive laser printers. But Press, a data format rather than a language, lacked flexibility, and PARC mounted the InterPress effort to create a successor. Bold text // Headline text Link title This article is about the computer research center. ... 1993 Apple LaserWriter Pro 630 laser printer A laser printer is a common type of computer printer that rapidly produces high quality text and graphics on plain paper. ... Dr. Robert F. Sproull works for Sun Microsystems and is a Sun Fellow, Vice President and Director of Sun Labs Massachusetts in Burlington. ... The Star workstation, officially known as the 8010 Star Information System, was introduced by Xerox Corporation in 1981. ... Bold text // Headline text Link title This article is about the computer research center. ... Interpress is a page description language developed at Xerox PARC, based on the Forth programming language. ...


In 1978 Evans and Sutherland asked Warnock to move from the San Francisco Bay Area to their main headquarters in Utah, but he was not interested in moving. He then joined Xerox PARC to work with Martin Newell. They rewrote Design System to create JaM (for "John and Martin") which was used for VLSI design and the investigation of type and graphics printing. This work later evolved and expanded into the InterPress language. Year 1978 (MCMLXXVIII) was a common year starting on Sunday (link displays the 1978 Gregorian calendar). ... USGS satellite photo of the San Francisco Bay Area. ... This article is about the U.S. state. ... Bold text // Headline text Link title This article is about the computer research center. ... Martin Newell is a computer scientist specializing in computer graphics, most famous as the creator of the Utah teapot. ... It has been suggested that VHSIC be merged into this article or section. ... Interpress is a page description language developed at Xerox PARC, based on the Forth programming language. ...


Warnock left with Chuck Geschke and founded Adobe Systems in December 1982. They created a simpler language, similar to InterPress, called PostScript, which went on the market in 1984. At about this time they were visited by Steve Jobs, who urged them to adapt PostScript to be used as the language for driving laser printers. Charles M. Chuck Geschke (born September 11, 1939) is best known as the co-founder with John Warnock of Adobe Systems Inc. ... Adobe Systems (pronounced a-DOE-bee IPA: ) (NASDAQ: ADBE) (LSE: ABS) is an American computer software company headquartered in San Jose, California, USA. Adobe was founded in December 1982[1] by John Warnock and Charles Geschke, who established the company after leaving Xerox PARC in order to develop and sell... Year 1982 (MCMLXXXII) was a common year starting on Friday (link displays the 1982 Gregorian calendar). ... Year 1984 (MCMLXXXIV) was a leap year starting on Sunday (link displays the 1984 Gregorian calendar). ... Steven Paul Jobs (born February 24, 1955) is the co-founder and CEO of Apple and was the CEO of Pixar until its acquisition by Disney. ... 1993 Apple LaserWriter Pro 630 laser printer A laser printer is a common type of computer printer that rapidly produces high quality text and graphics on plain paper. ...


In March of 1985, the Apple LaserWriter was the first printer to ship with PostScript, sparking the desktop publishing (DTP) revolution in the mid-1980s. The combination of technical merits and widespread availability made PostScript a language of choice for graphical output for printing applications. For a time an interpreter (sometimes referred to as a RIP -for Raster Image Processor) for the PostScript language was a common component of laser printers, into the 1990s. Year 1985 (MCMLXXXV) was a common year starting on Tuesday (link displays 1985 Gregorian calendar). ... Apple Inc. ... The Apple LaserWriter was one of the first laser printers available to the mass market. ... Adobe InDesign CS2, one of many popular desktop publishing applications. ... This article does not cite any references or sources. ... An interpreter is a computer program that executes other programs. ... A raster image processor (RIP) is a component used in a printing system which produces a bitmap. ... 1993 Apple LaserWriter Pro 630 laser printer A laser printer is a common type of computer printer that rapidly produces high quality text and graphics on plain paper. ... For the band, see 1990s (band). ...


Once the de facto standard for electronic distribution of final documents meant for publication, PostScript is steadily being supplanted by one of its own descendants, the Portable Document Format or PDF in this area. By 2001 there were fewer printer models which came with support for PostScript, largely due to the growing competition from much cheaper non-PostScript ink jet printers (PostScript interpreters added significantly to printer cost), and new software-based methods to render PostScript images on the computer, making them suitable for any printer (PDF provided one such method). The use of a PostScript laser printer still can, however, significantly reduce the CPU workload involved in printing documents, transferring the work of rendering PostScript images from the computer to the printer. De facto is a Latin expression that means in fact or in practice. It is commonly used as opposed to de jure (meaning by law) when referring to matters of law or governance or technique (such as standards), that are found in the common experience as created or developed without... The Portable Document Format (PDF) is the file format created by Adobe Systems in 1993 for document exchange. ... Year 2001 (MMI) was a common year starting on Monday (link displays the 2001 Gregorian calendar). ...


PostScript Level 1

The PostScript language has had two major upgrades. The first version, known as PostScript Level 1, was introduced in 1984. Year 1984 (MCMLXXXIV) was a leap year starting on Sunday (link displays the 1984 Gregorian calendar). ...


PostScript Level 2

PostScript Level 2 was introduced in 1991, and included several improvements: improved speed and reliability, support for in-RIP separations, image decompression (for example, JPEG images could be rendered by a PostScript program), support for composite fonts, and the form mechanism for caching reusable content. Year 1991 (MCMXCI) was a common year starting on Tuesday (link will display the 1991 Gregorian calendar). ... Image compression is the application of Data compression on digital images. ... JPG redirects here. ... In typography, a typeface is a co-ordinated set of character designs, which usually comprises an alphabet of letters, a set of numerals and a set of punctuation marks. ...


PostScript 3

PostScript 3 (Adobe dropped the "level" terminology in favor of simple versioning) came at the end of 1997, and along with many new dictionary-based versions of older operators, introduced better color handling, and new filters (which allow in-program compression/decompression, program chunking, and advanced error-handling). For the band, see 1997 (band). ...


PostScript 3 was significant in terms of replacing the existing proprietary color electronic prepress systems, then widely used for magazine production, through the introduction of smooth shading operations with up to 4096 shades of grey (rather than the 256 available in PostScript 2), as well as DeviceN, a color space that allowed the addition of additional ink colors (called spot colors) into composite color pages. // Definition of Spot Color In offset printing, a spot color is any color generated by an ink (pure or mixed) that is printed using a single run. ...


Usage in printing

Before PostScript

Prior to the introduction of PostScript, printers were designed to print character output given the text—typically in ASCII—as input. There were a number of technologies for this task, but most shared the property that the glyphs were physically difficult to change, as they were stamped onto typewriter keys, bands of metal, or optical plates. Image:ASCII fullsvg There are 95 printable ASCII characters, numbered 32 to 126. ... variant glyphs representing the character a (allographs of a) in the Zapfino typeface. ... Mechanical desktop typewriters, such as this Underwood Five, were long time standards of government agencies, newsrooms, and sales offices. ...


This changed to some degree with the increasing popularity of dot matrix printers. The characters on these systems were "drawn" as a series of dots, the proper dots to use defined as a font table inside the printer. As they grew in sophistication, dot matrix printers started including several built-in fonts from which the user could select, and some models allowed users to upload their own custom glyphs into the printer. A dot matrix printer or impact matrix printer refers to a type of computer printer with a print head that runs back and forth on the page and prints by impact, striking an ink-soaked cloth ribbon against the paper, much like a typewriter. ... For the origin and evolution of fonts, see History of western typography. ...


Dot matrix printers also introduced the ability to print raster graphics. The graphics were interpreted by the computer and sent as a series of dots to the printer using a series of escape sequences. These printer control languages varied from printer to printer, requiring program authors to create numerous drivers. Suppose the smiley face in the top left corner is an RGB bitmap image. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... PCL (Printer Command Language) was developed by HP as a printer protocol that has become a de facto industry standard. ... Windows XP loading drivers during a Safe Mode bootup A device driver, or a software driver is a specific type of computer software, typically developed to allow interaction with hardware devices. ...


Vector graphics printing was left to special-purpose devices, called plotters. Plotters did share a common command language, HPGL, but were of limited use for anything other than printing graphics. In addition, they tended to be expensive and slow, and thus rare. This article or section does not cite its references or sources. ... HPGL, sometimes hyphenated as HP-GL, is the primary printer control language used by Hewlett-Packard plotters. ...


PostScript printing

PostScript broke with tradition by combining the best features of both printers and plotters. Like plotters, PostScript offered high quality line art and a single control language that could be used on any brand of printer. Like dot-matrix printers, PostScript offered simple ways to generate pages of text and raster graphics. Unlike either, PostScript could place all of these types of media on a single page, which offered far more flexibility than any printer or plotter previously had.


PostScript went beyond the typical printer control language and was a complete programming language of its own. Many applications can transform a document into a PostScript program whose execution will result in the original document. This program can be sent to an interpreter in a printer, which results in a printed document, or to one inside another application, which will display the document on-screen. Since the document-program is the same regardless of its destination, it is called device-independent. An interpreter is a computer program that executes other programs. ...


PostScript is noteworthy for implementing on-the fly rasterization; everything, even text, is specified in terms of straight lines and cubic Bézier curves (previously found only in CAD applications), which allows arbitrary scaling, rotating and other transformations. When the PostScript program is interpreted, the interpreter converts these instructions into the dots needed to form the output. For this reason PostScript interpreters are also sometimes called PostScript Raster Image Processors, or RIPs. Rasterization is the task of taking an image described in an outline format, and converting it into a series of dots for output on a dot matrix display or printer. ... Cubic Bézier curve In the mathematical field of numerical analysis, a Bézier curve is a parametric curve important in computer graphics. ... CAD is a TLA that may stand for: Cadiz Railroad (AAR reporting mark CAD) Canadian dollar – ISO 4217-code Capital Adequacy Directive Card Acceptance Device Children of the Anachronistic Dynasty Computer-aided design Computer-aided detection (medical) Computer-aided diagnosis (medical) Computer-assisted dispatch Computer-assisted drafting Coronary artery disease... A raster image processor (RIP) is a component used in a printing system which produces a bitmap. ...


Font handling

Almost as complex as PostScript itself was its handling of fonts. The rich font system used the PS graphics primitives to draw glyphs as line art, which could then be rendered at any resolution. Though this sounds like a reasonably straightforward concept, there were a number of typographic issues that had to be considered. For the origin and evolution of fonts, see History of western typography. ... It has been suggested that this article or section be merged into Line Art. ... Image resolution describes the detail an image holds. ... Typographic work Typography (from the Greek words typos = form and grapho = write) is the art and technique of selecting and arranging type styles, point sizes, line lengths, line leading, character spacing, and word spacing for typeset applications. ...


One is that fonts do not actually scale linearly at small sizes; features of the glyphs will become proportionally too large or small and they start to "look wrong." PostScript avoided this problem with the inclusion of hints which could be saved along with the font outlines. Basically they are additional information in horizontal or vertical bands that help identify the features in each letter that are important for the rasterizer to maintain. The result was significantly better-looking fonts even at low resolution; it was formerly believed that hand-tuned bitmap fonts were required for this task. A font test with (lower rows) and without hinting (upper rows) at 100% (above) and 400% (below). ...


At the time, the technology for including these hints in fonts was carefully guarded, and the hinted fonts were compressed and encrypted into what Adobe called a Type 1 Font (also known as PostScript Type 1 Font, PS1, T1 or Adobe Type 1). Type 1 was effectively a simplification of the PS system to store outline information only, as opposed to being a complete language (PDF is similar in this regard). Adobe would then sell licenses to the Type 1 technology to those wanting to add hints to their own fonts. Those who did not license the technology were left with the Type 3 Font (also known as, PostScript Type 3 Font, PS3 or T3). Type 3 fonts allowed for all the sophistication of the PostScript language, but without the standardized approach to hinting. Other differences further added to the confusion. PostScript (PS) is a page description language used primarily in the electronic and desktop publishing areas. ... Type 1 outline fonts (also known as, PostScript, PostScript Type 1, PS1, T1 or Adobe Type 1) and Type 3 outline fonts (also known as, PostScript Type 3 or PS3, T3 or Adobe Type 3) were developed by Adobe for professional digital typesetting. ...


Type 2 was designed to be used with the Compact Font Format (CFF) font, and were implemented for a compact representation of the glyph description procedures to reduce the overall font file size. And later, the CFF/Type2 format became basis for Type 1 OpenType fonts. Compact Font Format (also known as, CFF font format, Type 2 font format, or, CFF/Type 2 font format,) is a font format specification developed by Adobe. ... Compact Font Format (also known as CFF font format, Type 2 font format, or CFF/Type 2 font format) is a font format specification developed by Adobe. ... Compact Font Format (also known as, CFF font format, Type 2 font format, or, CFF/Type 2 font format,) is a font format specification developed by Adobe. ... OpenType is a scalable computer font format initially developed by Microsoft, later joined by Adobe Systems. ...


CID-keyed font format was also designed, to solve the problems in the OCF/Type 0 fonts, for addressing the complex Asian-language (CJK) encoding and very large character set issues. CID-keyed font format can be used with the Type 1 font format for standard CID-keyed fonts, or Type 2 for CID-keyed OpenType fonts. CID Fonts (also known as, CID-keyed Fonts, CID-based Fonts) are a form of Type 1, PostScript font, capable of addressing large amount of glyphs. ... CJK is a collective term for Chinese, Japanese, and Korean, which comprise the main East Asian languages. ...


Adobe's rates were widely considered to be prohibitively high, and it was this issue[citation needed] that led Apple to design their own system, TrueType, around 1991. Immediately following the announcement of TrueType, Adobe published the specification for the Type 1 font format. Retail tools such as Altsys Fontographer (on January 1995 acquired by Macromedia, owned by FontLab since May 2005) added the ability to create Type 1 fonts. Since then, many free Type 1 fonts have been released; for instance, the fonts used with the TeX typesetting system are available in this format. TrueType is an outline font standard originally developed by Apple Computer in the late 1980s as a competitor to Adobes Type 1 fonts used in PostScript. ... Fontographer is a software application from Macromedia used to design fonts, available in both Windows and Apple Macintosh platforms. ... Macromedia was an American graphics and web development software house headquartered in San Francisco, California producing such products as Macromedia Flash. ... FontLab is both the name of a company, FontLab Ltd, and the former name of their flagship product, now called FontLab Studio. ... TeX (IPA: as in Greek, often in English; written with a lowercase e in imitation of the logo) is a typesetting system created by Donald Knuth. ...


In the early 1990s there were several other systems for storing outline-based fonts, developed by Bitstream and METAFONT for instance, but none included a general-purpose printing solution and they were therefore not widely used as a result. For the band, see 1990s (band). ... Bitstream Inc. ... METAFONT is a programming language used to define vector fonts. ...


In the late 1990s, Adobe joined Microsoft in developing OpenType, essentially a functional superset of the Type 1 and TrueType formats. When printed to a PostScript output device, the unneeded parts of the OpenType font are omitted, and what is sent to the device by the driver is the same as it would be for a TrueType or Type 1 font, depending on which kind of outlines were present in the OpenType font. OpenType is a scalable computer font format initially developed by Microsoft, later joined by Adobe Systems. ...


Other implementations

In the 1980s, Adobe got most of their revenue from the licensing fees for their implementation of PostScript for printers, known as a raster image processor or RIP. As a number of new RISC-based platforms became available in the mid 1980s, some found Adobe's support of the new machines to be lacking. A raster image processor (RIP) is a component used in a printing system which produces a bitmap. ... Reduced Instruction Set Computer (RISC), is a microprocessor CPU design philosophy that favors a smaller and simpler set of instructions that all take about the same amount of time to execute. ... This article does not cite any references or sources. ...


This and issues of cost led to third-party implementations of PostScript becoming common, particularly in low-cost printers (where the licensing fee was the sticking point) or in high-end typesetting equipment (where the quest for speed demanded support for new platforms faster than Adobe could provide). At one point, Microsoft and Apple teamed up to try to unseat Adobe's laser printer monopoly, Microsoft licensing to Apple a PostScript-compatible interpreter it had bought called TrueImage, and Apple licensing to Microsoft its new font format, TrueType. (Apple ended up reaching an accord with Adobe and licensed genuine PostScript for its printers, but TrueType became the standard outline font technology for both Windows and the Macintosh.) Some third-party PostScript-compatible interpreters are still widely used in printers, particularly Phoenix Page, which is standard in black-and-white Hewlett-Packard laser printers (as of 2006). TrueImage is a PostScript-compatible interpreter (clone) originally developed by Cal Bauer and Bauer Enterprises and sold to Microsoft in 1989. ... TrueType is an outline font standard originally developed by Apple Computer in the late 1980s as a competitor to Adobes Type 1 fonts used in PostScript. ... ... 2006 is a common year starting on Sunday of the Gregorian calendar. ...


Many basic, inexpensive laser printers don't support PostScript, instead coming with drivers that simply rasterize the platform's native graphics formats rather than converting them to PostScript first. When PostScript support is needed for such a printer, a free PostScript-compatible interpreter called Ghostscript can be used. Ghostscript prints PostScript documents on non-PostScript printers using the CPU of the host computer to do the rasterization, sending the result as a single large bitmap to the printer. Ghostscript can also be used to preview PostScript documents on a computer monitor and to convert PostScript pages into raster graphics such as TIFF and PNG, and vector formats such as PDF. Clockwise from top: The logo of the GNU Project (the GNU head), the Linux kernel mascot Tux the Penguin, and the FreeBSD daemon Free software is a term coined by Richard Stallman and the Free Software Foundation[1] to refer to software that can be used, studied, and modified without... Ghostscript is a suite of software based on an interpreter for Adobe Systems PostScript and Portable Document Format (PDF) page description languages. ... Die of an Intel 80486DX2 microprocessor (actual size: 12×6. ... Suppose the smiley face in the top left corner is an RGB bitmap image. ... This article is about TIFF, the computer image format. ... PNG (Portable Network Graphics) is a bitmapped image format that employs lossless data compression. ... The Portable Document Format (PDF) is the file format created by Adobe Systems in 1993 for document exchange. ...


Very high-resolution devices, such as imagesetters or CTP platesetters, in which resolutions exceeding 2500 dpi are not uncommon, still require external RIPs with large amounts of memory and hard drive space. Very high-end laser printer systems (known as digital presses) also use an external RIP to separate the more readily-upgradable computer from the specialized printing hardware. Companies such as EFI and Xitron specialize in such RIP software. An imagesetter is an ultra-high resolution large-format computer output device. ... Computer to plate (CTP) is an imaging technology used in modern printing processes. ... A platesetter is a machine which configures a lithographic plate. ...


Usage as a display system

With PostScript becoming a de facto standard for printed output, it was natural to consider using the same language for describing the screen output as well. The rapid increase in CPU power in the late 1980s, combined with an interest in windowing systems, led to several attempts to create a display system that used PostScript as its primary display technology. Die of an Intel 80486DX2 microprocessor (actual size: 12×6. ... This article does not cite any references or sources. ...


There are a number of advantages to using PS as the display system. One is that the fonts on other systems required the user to keep not only bitmaps for the screen, but also Type 1 for the printer. Using PS on the display would eliminate this and require only one set. Another advantage is that it allows for the "dumbing down" of printers. When the LaserWriter was released it was the most powerful (and expensive) machine in Apple's lineup, a result of needing considerable processing power and memory to render the page at a "high" resolution of 300 dpi in a reasonable amount of time. In contrast, the 400-dpi printer that shipped with the NeXT platform contained no image renderer at all, instead using the computer's CPU to do the rendering and passing the rendered page as a bitmap to the printer. (See also GDI printer.) Dots per inch (DPI) is a measure of printing resolution, in particular the number of individual dots of ink a printer or toner can produce within a linear one-inch (2. ... For other meanings, see Next. ... For the use of the term raster in radio regulation, see frequency raster. ... GDI is short for Graphics Device Interface or Graphical Device Interface, and is one of the three core components or subsystems of Microsoft Windows. ...


But the main advantage in using PostScript as a windowing system is that it allows one to write desktop publishing (DTP) and other graphically-intensive applications with a single set of graphics routines. The same code that is drawing to the window can be used to draw to the printer without any translation. DTP applications on traditional systems require the programmer to construct the GUI editor in the platform's own graphics system (for example, QuickDraw on the Macintosh, or Graphics Device Interface (GDI) on Microsoft Windows) and then write additional code to translate the graphics into proper PostScript for printing. This often takes up the majority of the programming effort on such projects and is a major source of bugs. Adobe InDesign CS2, one of many popular desktop publishing applications. ... GUI can refer to the following: GUI is short for graphical user interface, a term used to describe a type of interface in computing. ... Two quickdraws. ... The first Macintosh computer, introduced in 1984, upgraded to a 512K Fat Mac. The Macintosh or Mac, is a line of personal computers designed, developed, manufactured, and marketed by Apple Computer. ... GDI is short for Graphics Device Interface or Graphical Device Interface, and is one of the three core components or subsystems of Microsoft Windows. ... Windows redirects here. ...


The two main examples of PostScript as a display technology are Display PostScript (DPS) and NeWS. They differed dramatically in terms of where the display logic was applied; in DPS the view system was left to the hosting OS, whereas under NeWS the entire display was written in PS and ran in a single complex interpreter. NeXT Computer Inc. ... This article does not cite any references or sources. ...


The language

PostScript is a Turing-complete programming language. Typically, PostScript programs are not produced by humans, but by other programs. However, it is possible to produce graphics or to perform calculations by hand-crafting PostScript programs. In computability theory a programming language or any other logical system is called Turing-complete if it has a computational power equivalent to a universal Turing machine. ...


PostScript is an interpreted, stack-based language (i.e. stack language) similar to Forth but with strong dynamic typing, data structures inspired by those found in Lisp, scoped memory and, since language level 2, garbage collection. The language syntax uses reverse Polish notation, which makes parentheses unnecessary, but reading a program requires some practice, because one has to keep the layout of the stack in mind. Most operators (what other languages term functions) take their arguments from the stack, and place their results onto the stack. Literals (for example numbers) have the effect of placing a copy of themselves on the stack. Sophisticated data structures can be built on the array and dictionary types, but cannot be declared to the type system, which sees them all only as arrays and dictionaries, so any further typing discipline to be applied to such user-defined “types” is left to the code that implements them. A stack-oriented programming language is one that relies on a stack machine model for passing parameters. ... A stack-oriented programming language is one that relies on a stack machine model for passing parameters. ... Forth is a programming language and programming environment, initially developed by Charles H. Moore at the US National Radio Astronomy Observatory in the early 1970s. ... In computer science, a type system defines how a programming language classifies values and expressions into types, how it can manipulate those types and how they interact. ... Lisp is a family of computer programming languages with a long history and a distinctive fully-parenthesized syntax. ... In computer science, garbage collection (GC) is a form of automatic memory management. ... Postfix notation is a mathematical notation wherein every operator follows all of its operands. ... Look up literal, literally in Wiktionary, the free dictionary. ...


Arithmetic

Further information: Reverse Polish notation

Example: Postfix notation is a mathematical notation wherein every operator follows all of its operands. ...

 3 4 add 5 1 sub mul 

will compute


Named variables

The previous example is nothing more than a RPN calculator. Of course, PostScript has variables. In detail, it has a dictionary stack where everything that is not a literal is looked up; on a match, the current value stored under the name is pushed (or rather, executed — see below); mismatches will result in an error. To place something in the current dictionary (i.e. the topmost dictionary on the dictionary stack) one needs the def operator, which takes a name and a value as its arguments. Names are constructed by prefixing (or quoting) with a slash. So Postfix notation is a mathematical notation wherein every operator follows all of its operands. ...

 /x1 15 def 

will first push the name "x1" on the stack, then the value 15, then execute def which will take both from the stack, and write 15 into the current dictionary under the name "x1". Later occurrences of "x1" (not to be confused with "/x1") will push 15 onto the stack as long as the variable is unchanged. This code will increment the content of x1 by 2, assuming x1 is already present in the current dictionary:

 /x1 x1 2 add def 

Stack operators

Several Postscript operators rearrange or manipulate the stack: duplicate (dup), discard (pop) and exchange (exch) operate on elements at the top of the stack, whereas roll rotates a specified section of the stack, copy duplicates a specified portion, and index lets you access the stack like an array.


Procedure definitions

Some programming utility is offered by { and }. The opening brace puts the interpreter in deferred execution mode, so that everything is just placed on the stack, even operators and other executable objects. The one exception is the closing brace, which takes everything put on the stack since the opening brace, bundles it up into an (anonymous) procedure, and places that on the stack.


This construct is used in various ways, for subroutine definition (the anonymous procedure is assigned to a variable), loops, conditionals, etc. Example:

 x1 0 eq { 0 } { 1 x1 div } ifelse 

This code first uses the eq operator to test whether the value of x1 is equal to 0; depending on the outcome eq will push true or false onto the stack. After that, two procedures are pushed onto the stack. Then ifelse is executed, which takes three arguments from the stack, and will execute either the second (if the third is true) or first (if the third is false). In summary, 0 results if x1 is 0, 1/x1 is the result for all other cases.

 /inc3 { 3 add } def 

Here def is used to place something in the dictionary, only this time it is a procedure instead of a simple integer. This works because the values coming from the dictionary are executed, not just pushed (as simplistically stated above). Since executing a literal amounts to pushing it, that did not make a difference before. Now executing "inc3" will first look it up in the dictionary, find the procedure object representing "{ 3 add }" and execute that. One value must reside on the stack for this to work, since add needs two arguments, only one of which is given in the procedure itself. Naturally, one passes arguments to procedures by placing them on the stack, so we can simply view "inc3" as a procedure that takes one argument. Example call: For other uses, see Dictionary (disambiguation). ...

 71 inc3 

will put 71 on the stack, which inc3 will increment by three, for a final result of 74.


Graphics manipulations

To produce graphics, PostScript uses an ordinary cartesian coordinate system. Fig. ...

 100 200 moveto 300 400 lineto stroke 

moves the "cursor" to the point with coordinates (100, 200) and then draws a line to the point (300, 400).

 50 70 moveto 100 200 50 80 100 100 curveto stroke 

produces a cubic Bézier curve from (50, 70) to (100, 100) with control points (100, 200) and (50, 80). Cubic Bézier curve In the mathematical field of numerical analysis, a Bézier curve is a parametric curve important in computer graphics. ...

 250 250 moveto (Wikipedia) show 

will create the text "Wikipedia" at coordinate location (250, 250), rendered in a preselected font (using a possible command string such as /Courier findfont 12 scalefont setfont)


Graphics are initially produced in the "user coordinate system" and may then optionally be rotated, scaled or skewed before being copied to the "device coordinate system" specifying the final output.

 200 300 translate 45 rotate 

will translate the contents of the user coordinate system 200 points upwards, 300 points to the right and rotate it 45 degrees before they are copied to the device coordinate system.


The character "%" is used to introduce comments in PostScript programs. As a general convention, every PostScript program should start with the characters "%!" so that all devices will properly interpret it as PostScript.


"Hello world"

And finally, a Hello World program, the customary way to show a small example of a complete program in a given language, might look like this in Postscript: A hello world program is a computer program that prints out Hello, World! on a display device. ...

 %!PS /Courier findfont 20 scalefont setfont 72 500 moveto (Hello world!) show showpage 

or if the output device has a console

 %!PS (Hello world!) = 

See also

Wikibooks has more about this subject:

Image File history File links Wikibooks-logo-en. ... Adobe Systems (pronounced a-DOE-bee IPA: ) (NASDAQ: ADBE) (LSE: ABS) is an American computer software company headquartered in San Jose, California, USA. Adobe was founded in December 1982[1] by John Warnock and Charles Geschke, who established the company after leaving Xerox PARC in order to develop and sell... Ghostscript is a suite of software based on an interpreter for Adobe Systems PostScript and Portable Document Format (PDF) page description languages. ... The Portable Document Format (PDF) is the file format created by Adobe Systems in 1993 for document exchange. ... Document Structuring Conventions, or DSC, is a set of standards for PostScript, based on the use of comments, which primarily specifies a way to structure a PostScript file and a way to expose that structure in a machine-readable way. ... It has been suggested that Vector monitor be merged into this article or section. ... For the origin and evolution of fonts, see History of western typography. ... This is a list of typefaces. ... In typography, a typeface is a co-ordinated set of character designs, which usually comprises an alphabet of letters, a set of numerals and a set of punctuation marks. ... NeXT Computer Inc. ... Encapsulated PostScript, or EPS, is a graphics file format. ... Postfix notation is a mathematical notation wherein every operator follows all of its operands. ... PostScript Printer Description (PPD) files are created by vendors to describe the entire set of features and capabilities available for their PostScript printers. ... Windows XP loading drivers during a Safe Mode bootup A device driver, or a software driver is a specific type of computer software, typically developed to allow interaction with hardware devices. ...

References

This article was originally based on material from the Free On-line Dictionary of Computing, which is licensed under the GFDL. This article does not cite any references or sources. ... Bold text // “GFDL” redirects here. ...


External links

NeXT Computer Inc. ...

PostScript hacks


  Results from FactBites:
 
Display PostScript - Wikipedia, the free encyclopedia (800 words)
As the name implies, DPS uses the PostScript (PS) imaging model and language to generate on-screen graphics.
While early versions of PostScript display systems were developed at Adobe, the full implementation of Display PostScript was developed by NeXT in cooperation with Adobe Systems, and made an official Adobe product with its own standards, documents and licensing requirements.
The new system, known as Quartz, is based on the PDF model in which the source of the image is not the PostScript code itself, but the result of interpreting that code.
PostScript - Wikipedia, the free encyclopedia (3383 words)
PostScript Level 2 was introduced in 1991, and included several improvements: improved speed and reliability, support for in-RIP separations, image decompression (for example, JPEG images could be accessed directly by a PostScript program), support for composite fonts, and the form mechanism for caching reusable content.
PostScript is also noteworthy for implementing on-the fly rasterization; everything, even text, is specified in terms of straight lines and cubic Bézier curves (previously found only in CAD applications), which allows arbitrary scaling, rotating and other transformations.
When printed to a PostScript output device, the unneeded parts of the OpenType font are omitted, and what is sent to the device by the driver is the same as it would be for a TrueType or Type 1 font, depending on which kind of outlines were present in the OpenType font.
  More results at FactBites »

 
 

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