Had to do some refactoring to make this happen...
Under uniscribe bug compatibility mode, we still plit them
Uniscrie-style, but Jonathan and I convinced ourselves that there is no
harm doing this the Unicode way. This change makes that happen, and
unbreaks free Sinhala fonts.
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...
The merger of normalizer and glyph-mapping broke shapers that
modified text stream. Unbreak them by adding a new preprocess_text
shaping stage that happens before normalizing/cmap and disallow
setup_mask modification of actual text.
If there is no GPOS, zero mark advances.
If there *is* GPOS and the shaper requests so, zero mark advances for
attached marks.
Fixes regression with Tibetan, where the font has GPOS, and marks a
glyph as mark where it shouldn't get zero advance.
When we removed the separate Hangul shaper, the specific normalization
preference of Hangul was lost. Fix that. Also, the Thai shaper was
copied from Hangul, so had the fully-composed normalization behavior,
which was unnecessary. So, fix that too.
According to Peter Constable this is indeed what Uniscribe has been
doing for years.
Mozilla Bug 667166 - wrong shape of letter when it comes at the end of
word in the arabic version of Firefox 5.0
Instead of always applying those two features before the complex shaper,
let the complex shaper decide whether they should be applied first.
Also add stub for Indic's final_reordering().
Fixes https://bugzilla.mozilla.org/show_bug.cgi?id=644184
among others.
Shapers now can request segmented feature application by calling
add_gsub_pause() or add_gpos_pause(). They can also provide a
callback to be called at the pause. Currently the Arabic shaper
uses pauses to enforce certain feature application. The Indic
shaper can use the same facility to pause and do reordering in the
callback.
Nothing functional in there yet.
So far, we're parsing IndicSyllabicCategory.txt and IndicMatraCategory.txt
fils from Unicode Character Database and store them in an array to be used
by the shaper. Also hooked up the shaper, but it does not do anything
right now.
Behdad Esfahbod