First, we were abusing OT_VD instead of OT_A. Fix that
but moving OT_A in the grammar where it belongs (which
is different from what the spec says).
Also, only allow medial consonants after all other
consonants. This doesn't affect any current character.
Finally, fix Halant attachment in presence of medial
consonants. Again, this currently doesn't affect any
sequence.
I lied. There's Gurmukhi U+0A75 which is Consonant_Medial.
Uniscribe allows one of those in each of these positions:
before matras, after matras and before syllable modifiers,
and after syllable modifiers! We currently just allow
unlimited numbers of it, before matras.
No panic, we reeally insert dotted circle when it's absolutely broken.
Fixes most of the dotted-circle cases against Uniscribe. (for Devanagari
fixes 80% of them, for Khmer 70%; the rest look like Uniscribe being
really bogus...)
I had to make a decision. Apparently Uniscribe adds one dotted circle
to each broken character. I tried that, but that goes wrong easily with
split matras. So I made it add only one dotted circle to an entire
broken syllable tail. As in: "if there was a dotted circle here, this
would have formed a correct cluster." That works better for split
stuff, and I like it more.
Following what the spec says.
Brings down Telugu failures from 40% to 3.75%, and Kannada failures from
44% to 10%. Does NOT affect other scripts' test results.
It's a visual Repha.
Still not positioning logical Repha as occurs in Malayalam.
Another 200 Khmer failures fixed. 547 to go. That's better than
Devanagari!
In Khmer, a final subjoined consonant or independent vowel can occur
after matras. This final subjoined thing should NOT be reordered to
before the matra even though it's subjoined.
Fixes another 1k of the Khmer failures. Not much left really.
We are going to split matras without a Unicode decompositions in a way
that the second half takes the codepoint of the whole matra. So,
position them where the second half is supposed to end up.
And this, concludes the HarfBuzz Massala Hackfest.
I like to specially thank Jonathan Kew for doing all the decription and
letting me get commit points.
For dotted-circle independent clusters, Uniscribe does no Reph shaping
for the exact sequence Ra+Halant+25CC. Which also is the only possible
sequence with 25CC at the end.
This introduced a failure, which we tracked down to a test case like this:
U+092E,U+094B,U+094D,U+0930
The final character is a Ra that should be put in a syllable of it's
own. And we do. But it will interact with the Halant before it. So
now we finally are convinced that we have to limit features to syllable
boundaries. That's coming after lunch!
Behdad Esfahbod