Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!uunet!husc6!rutgers!mcnc!unc!steele From: steele@unc.cs.unc.edu (Oliver Steele) Newsgroups: comp.graphics,comp.windows.misc Subject: Re: PostScript standard? Message-ID: <1628@unc.cs.unc.edu> Date: Wed, 14-Oct-87 20:18:40 EDT Article-I.D.: unc.1628 Posted: Wed Oct 14 20:18:40 1987 Date-Received: Fri, 16-Oct-87 06:38:02 EDT References: <535@micas.UUCP> <15085@topaz.rutgers.edu> <532@gssc.UUCP> <482@tnosel.UUCP> Reply-To: steele@unc.UUCP (Oliver Steele) Organization: University of North Carolina, Chapel Hill Lines: 47 Xref: mnetor comp.graphics:1263 comp.windows.misc:82 hvt@tnosel.UUCP (henq) writes: >In article 'Re: PostScript standard?' John D. Miller writes: >> how many times do you sit down at the terminal and write a >> program that describes the page you want printed? > >if you program on a Mac, *all* you do is making programs >that describe pages to be printed (WYISWYG, remember ?) >and..who wants hardware specific, manufacturer specific, >resolution dependant programs these days ? Curious example. In the Mac world, it's the PostScript-specific prgrams that *are* hardware specific, or at least relatively so. Most applications use QuickDraw, which is the true DeVice Independent (DVI) Macintosh Page Description Language (PDL): it works on any screen cards you put into the Mac, and is mapped by the printer driver into the PDL supported by the chosen printer (bit streams for dot matrices and General Computer's laserwriter, PS for other laserwriters, and other formats for plotters and other printers). If your application describes a page in PS, it can only use this description for output to PS printers; if it describes a page in QuickDraw, it can use this description for screen drawing, non-PS printers, *and* PS printers. The moral of this is that if you have a sufficiently powerful PDL built into the computer, and DVI printing in the OS, it doesn't matter what PDL your printers use as long as your printers can print at a high enough resolution to render your page the way you described it. Fonts are a different story, but fonts can be (*can be*, but often aren't) abstracted from the PDL itself. A standard PDL among printers is a boon for the IBM family because (1) IBM doesn't have a sufficiently powerful PDL to fill the bill, and (2) IBM doesn't have a DVI print driver in the OS. Actually, QuickDraw on the Macs doesn't quite fill the bill, else Mac programs that *do* deal specifically with PostScript wouldn't be necessary (nor would certain kludgy things that have to do with the different interpretation of certain picture opcodes by the screen driver and the printer driver). The deficiencies include limitations on rotated text and the types and ranges of shading, among other things. So the moral still holds, but the example is weak (still, not bad for four-year-old architecture. Anything newer ought to be better, but this doesn't seem to hold). ------------------------------------------------------------------------------ Oliver Steele ...!{decvax,ihnp4}!mcnc!unc!steele steele%unc@mcnc.org "'As it were' means 'I think that I sound very erudite.' 'Per se' is Latin for 'as it were.' As it were."