Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!utgpu!water!watmath!clyde!rutgers!ames!ucbcad!ucbvax!RICE.EDU!phil From: phil@RICE.EDU.UUCP Newsgroups: comp.laser-printers Subject: Re: PostScript vs DDL vs Interpress (was PostSript Printers) Message-ID: <8704171639.AA10588@brillig.umd.edu> Date: Mon, 13-Apr-87 09:28:57 EST Article-I.D.: brillig.8704171639.AA10588 Posted: Mon Apr 13 09:28:57 1987 Date-Received: Sat, 18-Apr-87 06:39:10 EST Sender: daemon@ucbvax.BERKELEY.EDU Distribution: world Organization: The ARPA Internet Lines: 57 Approved: laser-lovers@brillig.umd.edu >From: gymble!harvard!topaz!unirot!patwood@brillig.umd.edu (Patrick Wood) > Since there are few people who have actually seen an Interpress and/or DDL > printer, it's hard for anyone to say anything that isn't based on some > manufacturer's claim or second-hand knowledge. Now let's hear from someone who not only has seen an Interpress printer, but worked on one during the summer of '84 writing Unix ditroff support software for it ......... me! > Xerox says that Interpress is designed for speed and is faster than > PostScript. Considering that the only version of Interpress that's > available now doesn't do graphics, only text and scanned images (no > vector graphics, clipping, or rotation of text), I can see why it's fast. Interpress IS designed for speed. Interpress files are 8 bit data and NOT ASCII. An Interpress command is one byte long instead of a space-terminated string of arbitrary length. This means faster interpretation on the printer server end and faster transfer time since Interpress files are smaller than, say, Postscript files. Now, it's been awhile, but I definitely remember line graphics and I definitely remember that that 8044 I used did them. I also remember, however, that it did not do circles and arcs and splines (I had to build bitmaps and ship those to do the equivalent ditroff graphics). But I'm almost positive that it did line graphics. What else would you mean by "vector graphics"? And it certainly does rotation of text. However, unlike Postscript, the standard Interpress server needs to store the fonts pre-rotated. So (although the standard does not make this restriction) no Interpress printers are capable of *arbitrary* rotation of text: they are capable of certain transformations. Adding more fonts gets more rotations. Clipping I never tried, so I can't say anything about that. > Read that any way you want, to me it means that > Interpress gains speed by giving up some flexibility. But not much flexibility. They gave up the ability for actions on one page to influence actions on another (nothing from one page carries over). It is not clear to me that such a "feature" is all that advantageous. The first part of every Interpress file is a "preamble". The state of the printer at the end of the preamble is used as the starting state for every page in the document. So, fonts and transformations and other global stuff is defined in the preamble and is then available at the beginning of every page. But one page can't do something (either intentionally or inadvertently) that affects pages later in the document. This make it MUCH easier to arbitrarily rearrange pages to your heart's content. I understand that this approach is *possible* in Postscript, but not *enforced*. This makes writing a program to rearrange any given Postscript file much harder. Right? William LeFebvre Department of Computer Science Rice University