In OT kern subtable header, the format is the high byte of 'coverage'
bit mask (bits 8-15), and the low byte (bits 0-7) is the actual coverage
bits.
In AAT kern, it's the opposite: the coverage flags are the high byte,
whereas the subtable format is the low byte.
Also adjusted the test data, and set coverage to 1 for OT kern subtable
(which means the usual horizontal kerning).
- When compiling kern subtables for version=1.0 kern tables (AAT)
the subtable header was written incorrectly: there is no version,
the length is a uint32 and there's an additional uint16 for
tupleIndex
- Use the 'coverage' low byte to select subtable "format", instead
of the 'version' field, only present in OT kern subtable header.
The getkern method was failing with AttributeError on 'unknown'
subtable formats, as their class only has 'format' instead of
'version' attribute. The 'version' attribute is renamed to
'format' also to avoid confusion, but the old one is kept for
backward compatiblity. In the only implemeted subtable class,
'format' becomes a class attribute rather than instance's
(it must always be 0).
- KernTable_format_0 now takes an 'apple=False' argument, used to
know the different headers and whether to read/write tupleIndex.
- minor pep8 whitespace and indentation fixes
- A new 'tupleIndex' attribute is written out to TTX for apple
kern subtables. Old ttx files which lack that attribute will
still be read (with a warning) and will default to tupleIndex=0
when recompiled or dumped with current fonttools.
Fixes#1089
This also fixes fonttools/fonttools/issues/1030.
Although the roundtrip is generally possible when a VariationStore is built from source font data using the Superpolator model, it is possible to build region definitions that do not follow this model. Behdad cited the Skia "Q" example, where the tail of the Q is affected by two regions defined as:
min=0 peak=0.5 max=0.51 delta=+10
min=0.49 peak=0.5 max=0.51 delta=-10
I need some font objects to exercise the fonts_to_quadratic function.
Defcon is still not an install requirement though, as cu2qu should
work with any defcon-like objects (e.g. fontParts?, robofab not so much)
When the 'max_err_em' argument is a float, we multiply it
by the font.info.unitsPerEm. However we were not doing it when
the argument is a list of floats...
We dropped robofab support. There is no reason to arbitrarily
drop any contour points. Anchors are handled as anchors in
latest ufoLib+defcon, also for UFO2. No more need to special-case.
This was needed for when we were supporting the old robofab.ufoLib
where anchors were represented as single-point-with-a-name contours.
With latest ufoLib, even when glif format is 1, anchors are
stored separately and are not drawn with pens (only proper contours
and components are passed on in the draw method).
So there is no longer need to special-case single points.
It's not the job of the cu2qu pens to filter those out.
Beyond composing ligatures, AAT finite-state transducers can also
execute insertion actions without rewriting existing glyphs. The
corresponding actions have almost the same structure as ligature
actions, so we can share a lot of the plumbing within fonttools.
This renaming is in preparation of a larger change to support `morx`
ables with insertions.
