Unfortunately if the font has GPOS and 'mark' feature does
not position mark on dotted-circle, our inserted dotted-circle
will not get the mark repositioned to itself. Uniscribe cheats
here.
If there is no GPOS however, the fallback positioning kicks in
and sorts this out.
I'm not willing to address the first case.
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.
This will eventually allow us to skip marks, as well as (fallback)
attach marks to ligature components of fallback-shaped Arabic.
That would be pretty cool. I kludged GDEF props in, so mark-skipping
works, but the produced ligature id/components will be cleared later
by substitute_start() et al.
Perhaps using a synthetic table for Arabic fallback shaping was a better
idea. The current approach has way too many layering violations...
Fixes consonant-position with old-spec Malayalam. Uniscribe seem to be
doing this. Fixes below-base La (eg. Pa,H,La) with AnjaliNewLipi.ttf.
Doesn't regress new-spec or other scripts.
This reverts commit 24dd4e5674.
Oops. My bad. The change _regressed_ Malayalam test suite, not
improved it. I'll redo it, differentiating between old-spec and
new-spec cases.
The MS Indic specs say "...all classifications are determined ... using
context-free substitutions." However, testing shows that MS's Malayalam
shapers (both old and new), "match" even if there is no zero-context rule.
We follow.
Fixes below-base La (eg. Pa,H,La) with AnjaliNewLipi.ttf (old spec).
Moreover, test suite Malayalam failures are down to 312 from 875! No
change in other scripts.
Current numbers:
BENGALI: 353996 out of 354285 tests passed. 289 failed (0.0815727%)
DEVANAGARI: 707339 out of 707394 tests passed. 55 failed (0.00777502%)
GUJARATI: 366489 out of 366506 tests passed. 17 failed (0.0046384%)
GURMUKHI: 60769 out of 60809 tests passed. 40 failed (0.0657797%)
KANNADA: 951086 out of 951913 tests passed. 827 failed (0.0868777%)
KHMER: 299106 out of 299124 tests passed. 18 failed (0.00601757%)
LAO: 53611 out of 53644 tests passed. 33 failed (0.0615167%)
MALAYALAM: 1047541 out of 1048416 tests passed. 875 failed (0.0834592%)
ORIYA: 42320 out of 42329 tests passed. 9 failed (0.021262%)
SINHALA: 271726 out of 271847 tests passed. 121 failed (0.0445103%)
TAMIL: 1091837 out of 1091837 tests passed. 0 failed (0%)
TELUGU: 970558 out of 970573 tests passed. 15 failed (0.00154548%)
TIBETAN: 208469 out of 208469 tests passed. 0 failed (0%)
Behdad Esfahbod