pc>You suggested that the industry may not be ready for 32-bit
codes. I had not thought about that. Glyph IDs in TrueType
fonts are 16-bit, I believe, so that is an issue for TrueType.
Also, you're very right that numbers are much less useful for
working with glyphs than mneumonic strings.
w>I don't think so. There shouldn't be a relation between
glyph IDs and input code points at all in TTFs! Cmaps have
been invented to establish the needed relationship.
What I meant was that for a typographer or script engineer, as
they are doing their development work, mneumonic string
identifiers will make their work easier. I certainly agree that
what goes on in code is another matter entirely, that numbers
are equally adequate, and that glyph IDs and codepoints are and
should be distinct.
w>I don't see the problem. You can always populate the PUA
with your own scripts; you don't need to care of any of these
assignments! If you properly separate input encoding from
glyph addressing, no problems will occur. E.g., you can assign
to code U+F012 your `foo' glyph, and at the same time you
access glyph `uniF012' mapped to another code point.
The overlapping of the Private Use Area and the Corporate Use
Subarea is only a concern if you want to do a 1-to-1
Unicode->Glyph mapping (e.g. for unknown glyphs or glyphs which
can't be handled by your rendering system) -- of course, it's a
shame that even recent software written by Apple, Adobe, or
Microsoft still rely on the 1-to-1 Unicode->Glyph model...
My impression of what Adobe was proposing was more than just
glyph IDs; they were talking about character assignments. They
were also talking about subdividing CUS (which is formally
defined only as a subset of PUA) in a cooperative fashion among
major developers. Just as there shouldn't be any need for me to
worry about assigning my characters to the same codepoints that
Adobe assigns their private characters, so there shouldn't be
any need for Adobe to worry about whether they assign their
private characters to the same codepoints as does Apple. Yet
Adobe appears to be worrying about this. Adobe is suggesting
that they and others work together to avoid the space that each
other uses. This appears to be asking for an de facto industry
standard of something that by definition should not become an
My biggest concern has to do with how software is implemented.
Because MS makes use of U+F020 - U+F0FF for symbols, it may not
be safe to assume that you will always be able to safely assign
your own characters in this range and expect them to work as
expected in, e.g., Word or, for that matter, on any Windows
app. MS's software may assume certain semantics for that range.
It is entirely up to MS what they choose to do in their
software, and anybody who wants to live with their software has
to deal with the decisions they made, or else buy from someone
else. Now, hopefully, MS developers won't make it hard for
others to use that range; indeed, I'm pretty confident that MS
won't do that. At present, I believe that MS software will
assume certain semantics for characters in this range only if
the selected font is flagged as "symbol". They can always
choose to do otherwise, though, and might be more inclined to
do so if they were cooperating with others regarding
allocations in the CUS.
MS software assumes particular semantics for characters in the
range U+F020 - U+F0FF only if the selected font is a symbol
font. That's not a problem. What if Adobe brings to market a
"Unicode-conformant" version of Pagemaker, and that version of
Pagemaker assumes that U+F64D is a TABULAR OLDSTYLE COLON SIGN,
regardless of what font is applied. I may intend for that to be
a TAI LUE LETTER HIGH KA, and not appreciate the fact that
Pagemaker will gladly wrap lines in the middle of words
following that letter. Granted, the question of how to make 3rd
party apps aware of the semantics of PUA characters is an open
question, but the answer is definitely not for developers to
make assumptions about those semantics.
Now, I haven't read all of the information on Adobe's site, so
I need to be careful that I'm not accusing them of something
when I don't know fully what they're doing. I don't know that
Pagemaker or other Adobe apps will behave as I've suggested in
the previous paragraph. My point is simply that I'm concerned
about some statements I've seen on Adobe's site with regard to
character assignments in PUA. I hope I've explained enough here
to show why that is a concern for me.
This archive was generated by hypermail 2.1.2 : Tue Jul 10 2001 - 17:20:43 EDT