Re: TTF and Unicode surrogates

From: David Goldsmith (
Date: Mon May 18 1998 - 16:10:09 EDT

Michael Everson ( wrote:

>>No, the subject of discussion is encoding fonts for characters on the
>>Ethereal Planes as if they held mandatory ligatures of surrogates.
>>Thus, a TrueType font for 10000 to 100FF would purport to contain
>>ligatures for D800+DC00 to D800+DCFF.
>Somehow, this makes me uncomfortable.

Actually, we've been testing it, and it works fine. The demonstration of
Pollard I gave at IUC 12 was done this way. So was the demo of conjoining

Expanding the cmap table to handle 32 bit characters is a massive
undertaking which would require a considerable investment by any OS
vendor. This is why I ask whether it's really necessary to do this for
the characters that are likely to be encoded outside Plane 0. Even if you
did expand the cmap, it still wouldn't handle all the parts of Unicode
that require more than a one-to-one character/glyph mapping.

Apple would much prefer not to have to revise our cmap support, since we
feel our 'mort' table solution is more than adequate.

As Mark Davis mentioned in another message, you can read more about
Apple's typographic technology at <>.

David Goldsmith
International and Text Department Architect
Apple Computer, Inc.

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