VDict mobile



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
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 Language Reference Manual" ("The Red Book"),
Adobe Systems, A-W 1985].
(2002-03-11)