The variation merger reuses matrix rows / entries when aligning kerning
matrices. Don't remap same DeviceTable twice. Alternative fix would
have been to not reuse objects but that slows things down.
Fixes https://github.com/fonttools/fonttools/issues/1206
While we optimize VarStore later, just deduping here reduces amount
of data we have to work with later by 8x in NotoSans-VF.ttf test
case. It's a cheap optimization, so do it.
Tests were failing on python 2.7.6 because array module doesn't accept
unicode strings (fixed in later 2.7.x releases).
An alternative fix would have been to cast array(str('h'), [...]) but
that seemed a bit too much, especially since varStore module doesn't
really do heavy text manipulation (there aren't other string literals).
We cannot use unicode_literals unconditionally, because of this and
similar issues in the stdlib. We should use it only when it makes sense
and reduces the frequency of u"".
Ouch! Shrinks NotoSans-VF.ttf GDEF VarStore further down.
Original was 1016278 bytes. Before this change it was optimizing
to 256145 bytes. With this change, it goes down to a mere 57127
bytes!!!
We don't need to cast to int when using the round function from py23,
as this is a backport of python3's built-in round and thus it returns
an int when called with a single argument.
Cleans up GDEF varstore as well.
What's left:
- In none of the varLib.merger Mergers we handle the CaretValueFormat3. That should be done,
even though no one uses this,
- GPOS/GSUB FeatureVariations are not applied. Shouldn't be hard.
- 'rvrn' should be folded into 'ccmp' or some other default feature.
