On Tue, Oct 1, 2013 at 3:10 PM, Richard Wordingham <[email protected]> wrote: > On Tue, 1 Oct 2013 08:26:29 +0700 > Theppitak Karoonboonyanan <[email protected]> wrote: > >> On Tue, Oct 1, 2013 at 5:49 AM, Richard Wordingham >> <[email protected]> wrote: > >> Relying on 'mkmk' is a little bit costly, as it would need two sets >> of glyphs under different GDEF's for each combining vowel. And >> currently, most fonts are not prepared for this. However, it looks >> more feasible to cover minority languages. > > I don't understand the need for 'two sets of glyphs under different > GDEF's for each combining vowel'.
For two practical reasons: - Most OpenType engines cannot properly handle a glyph with both Base Mark and Mark anchors in the same glyph. Either one works and the other doesn't. And the safest solution is to make another copy of the glyph with different anchors. (I may be wrong with this. But it works well so far.) - A best practice for Thai typography is to provide smaller glyph for Mark than Base Mark of the same character. You can see such common practice for tone marks, for example, in most Thai fonts in the market. > On the other hand, a mkmk lookup > might become about 7 times as large when one includes all pairs of > marks above. Combinations of marks below with one another further > increase the amount of mkmk lookup. Yes, that's right. Regards, -- Theppitak Karoonboonyanan http://linux.thai.net/~thep/ _______________________________________________ HarfBuzz mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/harfbuzz
