Hi Behdad, Will the approach of using DFLT script work with a multi a multiscript font? I.e. if I need to support Arabic (Jawi), Western Cham and Khmer?
And if I need to support reordering and ligatures DFLT will be ok? Are all OT features supported by DFLT or only some? Andrew On 10/12/2012 6:42 PM, "Behdad Esfahbod" <[email protected]> wrote: > On 12-11-14 08:36 PM, Theppitak Karoonboonyanan wrote: > > On Thu, Nov 15, 2012 at 2:53 AM, Behdad Esfahbod <[email protected]> > wrote: > >> On 12-11-14 01:15 AM, Theppitak Karoonboonyanan wrote: > >>> On Tue, Nov 13, 2012 at 4:45 AM, Behdad Esfahbod <[email protected]> > wrote: > >>>> Ed! > >>>> > >>>> There's no way we can fix these without a font! Just send the font > first > >>>> already :). Jonathan and I are having yet another HarfBuzz Hackfest > week this > >>>> week and like to address the remaining issues for "Tai *" scripts :). > >>> > >>> While waiting for Ed, you may try Khottabun font for Lao/Esaan Tham > script, > >>> another Tai Tham variation used in Lao and northeastern Thailand: > >>> > >>> http://linux.thai.net/~thep/esaan-scripts/fonts/Khottabun.ttf > >>> > >>> The font, however, has provided all the reordering rules in GSUB, so > that it > >>> can still display on absence of rendering engine preprocessing. It may > not be > >>> good for your testing, but you can get some idea of the requirements > from it. > >> > >> Humm. Then it's not interesting indeed. Even worse, those rules may > conflict > >> with the engine processing :|. > > > > I know. That's why I said it might not be good for your testing. Just > hope to > > provide some sample for comparison using another system without the > > processing. > > Our current recommendation is that if your font does NOT rely on the engine > reordering, it's best to use the DFLT script. In HarfBuzz we use that > clue to > decide whether to use the Indic shaper or the generic shaper. In some > cases, > using a font designed for the generic shaper with the Indic shaper can > produce > inferior results. > > > > And I hope the sample text in the test page could still be some help. > > > > One common case that's still missing in the test page, though, is "ᨯᩪᩕᩣ", > > where MEDIAL RA has to be shifted left by two positions. > > The sequence is: > > > > U+1A2F TAI THAM LETTER DA > > U+1A6A TAI THAM VOWEL SIGN UU > > U+1A55 TAI THAM CONSONANT SIGN MEDIAL RA > > U+1A63 TAI THAM VOWEL SIGN AA > > > > And the rendered sequence should be: > > > > U+1A55 TAI THAM CONSONANT SIGN MEDIAL RA > > U+1A2F TAI THAM LETTER DA > > U+1A6A TAI THAM VOWEL SIGN UU > > U+1A63 TAI THAM VOWEL SIGN AA > > Right. This behavior is like the medial Ra in Myanmar, so should be fine > when > we implement that. > > > > Regarding the font development, since we want to make progress on other > > parts of the language support, such as input method, adding GSUB is all > > we can do while the rendering engine supports are still lacking. > > > > Once HarfBuzz supports it, I'll remove the rules and distribute two > > different versions of the font, one for HarfBuzz, the other for other > > engines. > > Or just ship one that has both a DFLT table, and a non-DFLT table. > > > > Regards, > > > > -- > behdad > http://behdad.org/ > _______________________________________________ > HarfBuzz mailing list > [email protected] > http://lists.freedesktop.org/mailman/listinfo/harfbuzz >
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