[XeTeX] The future of XeTeX

[Khaled Hosny]

On Tue, Jul 31, 2012 at 02:54:29PM +0100, Jonathan Kew wrote:
> On 31/7/12 14:36, mskala at ansuz.sooke.bc.ca wrote:
> >On Tue, 31 Jul 2012, Jonathan Kew wrote:
> >>On 31/7/12 13:26, mskala at ansuz.sooke.bc.ca wrote:
> >>>There's the rub.  Non-Latin scripts are a big part of the constituency of
> >>>XeTeX.  I routinely have to manually activate Korean-specific OpenType
> >>>features that are specified to be default but that XeTeX/fontspec doesn't
> >>>activate by default, just to get acceptable output in Korean at all.
> >>
> >>Which specific features are you referring to here? Maybe we can get this
> >>improved...
> >
> >ccmp - glyph (de)composition; and ljmo, vjmo, and tjmo - lead, vowel, and
> >tail jamo shaping.  It's possible that ccmp may already be default, and my
> >own application doesn't actually need tjmo, but both should be turned on
> >for Korean when available.
> 
> Hmm, I thought these would be active if you set "script=hang" (plain
> xetex) or [Script=Hangul] (xelatex+fontspec) in the font
> declaration. But on taking a quick look at the code in
> XeTeXOTLayoutEngine.cpp, I think it's broken: it incorrectly sends
> Hangul to the same code path as Han. :( Sorry - that's a bug!

What is the difference between XeTeXHanLayoutEngine and ICU's
HanOpenTypeLayoutEngine? In other words, would it be enough to just use
ICU's Hangul engine, or there are adjustments needed?

Regards,
 Khaled