[pdftex] textrace unique number?

[Y&Y Support]

At 12:55 2001-06-05 +0200, Berthold Crysmann wrote:
>Sherlock Holmes wrote:
>
> > Can someone tell me what the role is of the unixque number textrace
> > needs when it produces .pfb files?
> >
>
>Or, put differently:
>
>Under what circumstances does it actually matter if two, though distinct
>fonts happen to have the same ID?
>
>If it does: How to make the ID unique given there are tons of Type1
>fonts out there?
>
>Berthold

To make sure you have a UniqueID you need to contact the
UniqueID coordinator at Adobe (Terry O'Donnell last I heard).

Many PS rasterizers cache glyphs based on UniqueID and
FontMatrix.  So if you have two jobs passing through a printer
that use different fonts with the same UniqueID then you may
see glyphs of the second font printing out as glyphs from
the first.

Adobe Type Manager (ATM) caches based on PS FontName and
FontMatrix instead, so there having a UniqueID is neither
important nor a protection from potential collisions.

Since apparently many PS interpreters these days use a rasterizer
derived from ATM in order to get the highest quality rendering,
it isn't clear whether they use UniqueID or FontName for caching.

It may also be that with the increase in speed caching is
less important. WIth a gray-level "anti-aliasing"/"font smoothing"
rasterizer you may not be able to afford to want to cache all possible
alignments of the glyph with the underlying pixel grid anyway.