[luatex] tibetan font support

[Norbert Preining]

On Di, 07 Jul 2009, Norbert Preining wrote:
> Now we have many more freely available fonts and I want to make them
> available for (la)tex, based on luatex, aleph, or whatever.

A bit a different question, but still interesting to me:

In fact what I would need are two hooks into the luatex engine, one that
reads the input character stream and does some transformation on it,
feeding back some arbitrary unicode glyphs. (That would be what have
been the OTP/OCP in Omega talk).

And one hook - don't know where it should fit in - that combines
does some magic to combine some glyphs to another glyph (Ligature
table).

My idea is that from one of some input systems (extended wylie, utf8
directly encoded) some normalization is done (like if the unicode input
stream contains already precomposed characters they would be split into
main + subjoined characters, for wylie input the textual analysis and
separationg into main and subjoined characters would be done). 

After that those chars (main + subjoin + subjoin + ... + vowel + vowel +
... + special sign + special sign ....) are checked against a list of
pre-combined chars and replaced. If there is no pre-combined in the font
use some semi-intelligent to use at least some partly precombined part.

Where would be the right place to hook that, how to write that? I would
(from my time when I wrote that in Omega/OTP) try that again in that
way, but that doesn't look like the future ...

Best wishes

Norbert

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Dr. Norbert Preining <preining at logic.at>        Vienna University of Technology
Debian Developer <preining at debian.org>                         Debian TeX Group
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