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From: liam@cs.qmw.ac.uk (William Roberts)
Newsgroups: comp.lang.postscript
Subject: Re: Why is Mac PostScript a problem
Keywords: mac postscript
Message-ID: <2514@sequent.cs.qmw.ac.uk>
Date: 16 Jul 90 11:20:15 GMT
References: <9674@hubcap.clemson.edu>
Organization: Computer Science Dept, QMW, University of London, UK.
Lines: 36

In <9674@hubcap.clemson.edu> philip@hubcap.clemson.edu (Philip L Harshman) writes:

>Why is this necessary?  Why is Apple's PostScript so non-standard?  And just
>what is it about the Apple LaserPrep file that gives other printer so much
>trouble?  I'd appreciate any info people can pass on about this.

Mac LaserPrep files are a problem because they make use of such
a wide range of PostScript esoterica and have built-in
assumptions about the kinds of printers they might be used
with. This is one reason why programs like PageMaker offer the
option of using their own (awful) PostScript prep files which
they supply for a wider range of printers.

As an example of the "gee whizz" approach that the Mac stuff
uses, they create a procedure which records the default clip
region in device coordinates, and call it at the beginning of
every page. Each page is started by executing a string
containing the names of some PostSCript routines (hence it
executes those routines - I have no idea why they do this...)

Some of the eexec stuff actually contains a string of gibberish
which is passed to cexec (is this 68000 code?), so that may
cause some hassle with printers onther than the LaserWriters.

The reason behind all this? I think it is just intended to be
non-encapsulated PostScript. Apple may simply be trying to make
it hard to include Mac postscript in other documents, presumably
on the grounds that PostScript is an output language intended
only for printers, and that document composition should be done
at an earlier stage.
-- 

William Roberts                 ARPA: liam@cs.qmw.ac.uk
Queen Mary & Westfield College  UUCP: liam@qmw-cs.UUCP
Mile End Road                   AppleLink: UK0087
LONDON, E1 4NS, UK              Tel:  071-975 5250 (Fax: 081-980 6533)