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From: glenn@heaven.woodside.ca.us (Glenn Reid)
Newsgroups: comp.lang.postscript
Subject: Re: Shorter version of PostScript "Recycle" symbol
Message-ID: <186@heaven.woodside.ca.us>
Date: 27 Jun 90 00:56:44 GMT
References: <6741@umd5.umd.edu> <185@heaven.woodside.ca.us> <6750@umd5.umd.edu>
Reply-To: glenn@heaven.UUCP (Glenn Reid)
Organization: Skyline Press, Woodside CA
Lines: 42

In article <6750@umd5.umd.edu> zben@umd5.umd.edu (Ben Cranston) writes:
>This is really neat, because the shell script logically *removed* the
>standard Adobe Illustrator header, and now Glenn is *adding* a header
>to make it even smaller.
>
>My experience with the shell script is that it makes small files smaller
>and large files larger.  This is not so counterintuitive when you realize
>that using a header instead of bare PS code is a trade-off.

What you really want the shell script to do is not to expand the
procedure calls back into raw PostScript, but to eliminate procedure
definitions from the prologue that are not called at all.  Or, replace
them with equivalently useful ones like I did as a post-process to your
output file.  In other words, keep track of which procedures are called
(like "c" or "f" or whatever) and rather than expanding them, just make
sure they are in the prologue (but none of the other stuff is).

The notion of prologue definitions without any script to call them
reaches its most absurd when you do a command-K dump of a Macintosh
print file or when you create an Adobe Illustrator 88 file with one
line or one character in it (in the Illustrator case, you get all
the color separation stuff and all the procedure definitions; something
like 12800 bytes of unused definitions).

The main purpose of defining prologue procedures is so that you can
represent the document in less space, and so it can execute more
efficiently.  But this effect is nullified (and in fact reversed)
when the document is short.

Just observations, of course, not value judgements.  Although applications
could keep track of what was drawn and write out a different prologue
accordingly, that's not very practical all of the time.  But then, neither
is a library of, say, 100 Illustrator drawings where 1.3 megabytes of
the disk space used is the same prologue saved over and over again, in
which large parts of the prologue are never used at all.

(Glenn) cvn

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