Re: ZWJ and Latin Ligatures

From: John H. Jenkins (
Date: Tue Jul 02 2002 - 12:30:04 EDT

On Tuesday, July 2, 2002, at 09:49 AM, Michael Everson wrote:

> At 09:41 -0600 2002-07-02, John H. Jenkins wrote:
>> Alas, but that's technically impossible. Both OT and AAT (I'm not sure
>> about Graphite) require that single characters map to single glyphs,
>> which are then processed.
> Hm? How do you handle the decomposed sequence A + COMBINING ACUTE? Surely
> that is a sequence of characters mapping to a single glyph.

Same process. In OT, of course, you could count on the glyph being
prenormalized (but this only works for stuff already in Unicode), or you
could use the GPOS table to properly form the accented form on-the-fly.

But neither technology allows the decomposed sequence to be mapped
directly to a single glyph.

> Just goes to show that I don't make proper Unicode fonts yet because the
> tools just aren't up to snuff.

We're working on it. :-)

>> (In OT, of course, you are also supposed to do some preprocessing in
>> character space, but that doesn't solve this problem.) It would be nice
>> to have a cmap format which maps multiple characters to single glyphs
>> initially.
> I always thought there was. Now I'm really confused as to how I would
> make a complex Indic syllable.

Same sort of thing. You put the glyph in the font and the instructions
for what sequence forms it in the GSUB or morx table.

John H. Jenkins

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