Re: IDS rendering and IDS analysis (was RE: Problems/Issues with

From: Deborah Goldsmith (
Date: Tue Apr 11 2000 - 17:48:30 EDT

on 4/11/2000 2:17 PM, Jungshik Shin <> wrote:

> Hmm, I thought ATSUI(?) of MacOS has something similar for Thai,
> Indic scritps and even for Hangul. That is, complex
> context-sensitive(pre-defined fixed) m to n mapping of characters to
> glyph indices. By the way, even a very primitive X11 rendering engine
> of bitmap fonts can emulate 'the effect'(generating glyphs on-the-fly)
> fed by justaposing a set of zero-width/negative-width(non-advancing)
> glyphs and final advancing glyph.

ATSUI does not currently compose glyphs on the fly. It can perform a
many-to-many character to glyph mapping (controlled by the font), but the
glyphs need to be in the font. You could certainly use ATSUI to map IDS
characters to ideographs, as long as the ideographs were already present in
the font.

There are some facilities for composing glyphs, but the compositions are
decided when the font is produced, not on the fly. You could achieve an
on-the-fly effect through use of strange advance values, though that would
require a lot of tweaking.

I would think it would be really hard to get good-looking glyphs composing
on the fly, but I suppose if you are just interested in legibility it could

Deborah Goldsmith
Manager, International Toolbox Group
Apple Computer, Inc.

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