PostScript
<language, text, graphics> A page description language based on work
originally done by John Gaffney at Evans and Sutherland in 1976, evolving
through "JaM" ("John and Martin", Martin Newell) at XEROX PARC, and finally
implemented in its current form by John Warnock et al. after he and Chuck
Geschke founded Adobe Systems, Inc. in 1982.
PostScript is an interpreted, stack-based language (like FORTH). It was used as
a page description language by the Apple LaserWriter, and now many laser
printers and on-screen graphics systems. Its primary application is to describe
the appearance of text, graphical shapes, and sampled images on printed or
displayed pages.
A program in PostScript can communicate a document description from a
composition system to a printing system in a device-independent way.
PostScript is an unusually powerful printer language because it is a full
programming language, rather than a series of low-level escape sequences. (In
this it parallels Emacs, which exploited a similar insight about editing tasks).
It is also noteworthy for implementing on-the fly rasterisation, from Bezier
curve descriptions, of high-quality fonts at low (e.g. 300 dpi) resolution (it
was formerly believed that hand-tuned bitmap fonts were required for this task).
PostScript's combination of technical merits and widespread availability made it
the language of choice for graphical output until PDF appeared.
The Postscript point, 1/72 inch, is slightly different from other point units.
An introduction.
["PostScript Language Reference Manual" ("The Red Book"), Adobe Systems, A-W
1985].
[Jargon File]
(2002-03-11)
Nearby terms:
Post Office Protocol « post-order traversal «
POSTQUEL «
PostScript » Postscript point » Post, Telephone
and Telegraph administration » POSYBL
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