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From: SMITHM@QUCDN.QueensU.CA
Newsgroups: comp.lang.postscript
Subject: Re: UniqueId in Font Dictionaries: Why?
Message-ID: <90327.103524SMITHM@QUCDN.QueensU.CA>
Date: 23 Nov 90 15:35:24 GMT
Organization: Queen's University at Kingston
Lines: 21

Thanks to James Farrow for pointing out that the name is UniqueID not
UniqueId.  It isn't Thanksgiving here in Canada but I do feel like a turkey...

I've now listed the UniqueIDs on two printers, one with Adobe fonts
and one with Imagen (UltraScript) fonts.  At the risk of embarassing myself
further, I'd still like to know how UniqueID is used.  The Green Book
program assumes that it is generating a unique ID by adding 1 to the
base font's ID.  This is true for the font in the example (Helvetica-Bold).
It wouldn't work for Century Schoolbook Bold Italic because its ID is one
less than Century Schoolbook Bold.

What happens if I generate a UniqueID that isn't unique?  As far as I can see,
the only way to guarantee uniqueness is to maintain a list of all the IDs in
use.  Obviously this can be done but it seems like a lot of trouble.  The Red
Book says that UniqueID is not necessarily present in all fonts.  Would I be
better off to leave UniqueID out of my fonts if I'm not willing to guarantee
uniqueness?

 Mike Smith                                  SMITHM@QUCDN.BITNET
 Queen's University                          Michael.D.Smith@QueensU.CA
 Computing and Communications Services       (613) 545-2024