<
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.
{
postscript/postscript.html">An introduction
(http://cs.indiana.edu/docproject/programming/postscript/postscript.html)}.
[
"PostScript Language Reference Manual" ("The Red Book"),
Adobe Systems, A-W 1985].
[
Jargon File]
(2002-03-11)