The code was setting GlyphClassDef.classDefs for the base font to an
empty dict then reading it from all fonts. It accidentally works when
creating variable fonts because the GlyphClassDef of the other fonts
will be used, but when mutating there is only one font.
Fix by reading the glyph classes before assigning to an empty dict.
When --recalc-bounds option is used the font extents in the head table
need to be updated, but since tables are lazy-loaded by default the
table will not be recompiled and will keep the old value. Force
recompiling the table by adding it to prune_post_subset tables, though
I’m not 100% sure this is the best approach.
Do not round them to integer, but let the caller do the rounding immediately before adding them to the default instance (or just before compiling the binary table as with glyf).
This ensures that the glyphs' left sidebearings are calculated in the same way as they were by varLib.mutator.
If we round deltas too early, then we may get off-by-one differences.
See the glyf table setCoordinates method where left sidebearings are computed.
varLib._GetCoordinates (which this method is copied from) did not return such data either.
The problem with also including component flags in the returned controls
tuple is that different masters may happen to have different component
flags (e.g. if one master has USE_MY_METRICS, another doesn't).
added a dummy STAT table to PartialInstancer-VF.ttx font that has all 4 AxisValue formats.
It doesn't have contain AxisValue for each fvar NamedInstance like the spec recommends, but it's ok for the sake of this test
The code tries to write the short format when some values as None, but
when writing the long format it would write any None value as is which
is invalid, use 0 for None values instead.
This required a fix to fontTools/cffLib. When reading a CFF2 variable font (VF) from XML, the VF state in FontDict and PrivateDict does not get set. I made a temporary fix by adding a loop to set PrivateDict.vstore for all the PrivateDict objects after the XML file has been read. This should not be necessary, and in the near future I will revisit both this issue, and the related use of isCFF2 when compiling/decompiling.
