From: John Jenkins (jenkins@apple.com)
Date: Wed Apr 28 2004 - 17:55:14 EDT
On Apr 28, 2004, at 2:19 PM, John Hudson wrote:
> The only interaction between glyphs in a font and character codes in 
> text is via mapping (which is done either internally or externally, 
> depending on the font format). Fonts do not contain any character 
> information other than which glyphs corrrespond to which characters. 
> All other information in the font is glyph-centric; e.g. ligature and 
> other substitution lookups map glyphs to glyphs, not characters to 
> glyphs. Trying to introduce character properties into such a 
> glyph-centric architecture would be, at best, an awkward fit.
>
FWIW, AAT includes an optional 'prop' table which allows people to 
associate a number of Unicode properties -- most notably directionality 
-- with specific glyphs in a font.  It *is* a little weird to do this, 
as John says, but it's there.
========
John H. Jenkins
jenkins@apple.com
jhjenkins@mac.com
http://homepage.mac.com/jhjenkins/
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