[HarfBuzz] Rendering Thai

[Behdad Esfahbod]

On 11/11/2011 04:41 AM, Theppitak Karoonboonyanan wrote:
> No. I mean, the default routine in harfbuzz should be fixed for this case.

So, can you please explain to me what the Thai-specific rendering requirements
are?

> The Qt patch will optionally dlopen() libthai if it's present, to improve
> the rendering quality. But without libthai installed, harfbuzz should
> still normalize the combining characters properly. No IPA is required
> for this case.

What's IPA?   I can only think of International Phonetic Alphabet, but can't
see how that would make sense in this paragraph.


> After that, the question would be whether harfbuzz would support
> IPA shaping. If the answer is yes, we can then decide whether to
> copy libthai code over, or to link against it, or to dlopen() it.

So what is IPA shaping?

HarfBuzz kinda normalizes text now.  Is it doing anything better?

If I understand correctly, this is related to the issue recently brought up by
Sairus (Adobe) on the OpenType list:

"It’s recently come to my attention that the MS Thai layout spec
http://www.microsoft.com/typography/otfntdev/thaiot/features.aspx  doesn’t
require layout engines to do the sara am decomposition and reordering. I’m
told that some engines do the sara am decomposition and reordering e.g.
Uniscribe and Adobe’s CTS, and others don’t e.g. Harfbuzz."

Are we talking about the same thing?  If yes, I can look into this.

behdad



> Regards,