[HarfBuzz] Rendering Thai

[John Tapsell]

2011/11/11 Theppitak Karoonboonyanan <thep at linux.thai.net>:
...
> Waree contains GSUB rules for proper substitutions, while Tahoma does not.
> Legacy fonts like Tahoma rely on composition-by-substitution, and requires the
> rendering engine to properly pick up IPA glyphs with vendor-specific
> code points.

Nokia has a custom-made font that also doesn't work.  Should we insist
to the font vendor that they add these GSUB rules?  Or is it perfectly
fine for them to have not added them?

> LibThai has such routine for both Windows and Mac. That's why the Qt patch
> helps.

And Linux it seems.  I've been testing this on linux.

> But I think harfbuzz default behavior should at least normalize the combining
> characters properly without the patch.

The Qt patch uses 5 functions from libthai.  Are you suggesting that I
work out which are required for the normalization, and copy the code
across into the patch so that the normalization works even without
libthai?

John