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.
* Added getter (in the form of a property decorator) for T2Charstring.vsindex. Fixes endless compile loop in some circumstances.
Fixed bug in mutator: need to remove vsindex from snapshotted charstrings, plus formatting clean up
* Fix for subsetting HVAR tables that have an AdvanceWidthMap when the --retain-gid option is used. Needed to make subset_test.py::test_retain_gids_cff2 tests pass.
* in varLib/cffLib.py, add support for sparse sources, and sources with more than one model, and hence more than one VarData element in the VarStore.
CFF2 source fonts with multiple FontDicts in the FDArray need some extra work. With sparse fonts, some of the source fonts may have a fewer FontDicts than the default font. The getfd_map function() builds a map from the FontDict indices in the default font to those in each region font. This is needed when building up the blend value lists in the master font FontDict PrivateDicts, in order to fetch PrivateDict values from the correct FontDict in each region font.
In specializer.py, add support for CFF2 CharStrings with blend operators. 1) In generalizeCommands, convert a blend op to a list of args that are blend lists for the following regular operator. A blend list as a default font value, followed by the delta tuple. 2) In specializeCommands(), convert these back to blend ops, combining as many successive blend lists as allowed by the stack limit.
Add test case for sparse CFF2 sources.
The test font has 55 glyphs. 2 glyphs use only 2 sources (weight = 0 and 100). The rest use 4 source fonts: the two end points of the weight axis, and two intermediate masters. The intermediate masters are only 1 design space unit apart, and are used to change glyph design at the point in design space. For the rest, at most 2 glyphs use the same set of source fonts. There are 12 source fonts.
Add test case for specializer programToCommands() and commandsToProgram by converting each CharString.program in the font to a command list, and back again, and comparing original and final versions.
The dunder method doesn't seem to be doing anything other than providing
an `in_cff2` attribute. Do that with a property instead of bending
__getattr__.
This one confused me when I was working on
https://github.com/fonttools/fonttools/pull/1488.
We need to raise AttributeError for non-existing dunder methods like
'__deepcopy__' or '__getstate__', because deepcopy() and pickle.load()
test for these on the instance using getattr() and treat the resulting
AttributeError as a signal that the object doesn't implement these custom
hooks. If we don't do that, we enter an infinite recursion as we attempt
to look up the missing dunder methods in the 'rawDict' dictionary,
because 'rawDict' is set inside __init__, but __init__ is not invoked
while unpickling (only __new__ is); thus self.rawDict is also missing
and __getattr__ is invoked with argument 'rawDict' again and again until
it crashes with RecursionError. Phew.
Fixes https://github.com/fonttools/fonttools/pull/1488
@bedhad
Address issues raised in #1403
I do think setting the dummy CFF2 PrivateDict nominalWidthX and defaultWidthX to None, which leads to the charstring.width also being None, is a good idea. I originally set them to 0, which produces a charstring width of 0, in order to avoid problems with logic that assumes that the field is good for math. However, I now think that it is better to find errors around charstring type assumptions earlier than later.
"drop_hints()" is actually not wrong - I did look at this when making the changes. For CFF2 charstrings, self.width is always equal to self.private.defaultWidthX, so the width is never inserted. This is because in psCharstrings.py::T2WidthExtractor.popallWidth(), the test "evenOdd ^ (len(args) % 2)" is alway False. Left to myself, I would not change this code. If the CFF2 charstring is correct, there is not a problem. if the CFF2 charstring is not correct, then both in drop_hints() and in T2WidthExtractor.popallWidth(), the logic will stack dump. I did add asserts, but am not totally sure it is worth the extra calls.
Removed check_program functions. Supporting these requires knowledge of CFF vs CFF2 state, whci is leads to wide-spread diffuse changes. Also, not needed - the endchar/return opcodes are removed when compiling for CFF2.
Removed CFF2Subr class. This was used for CFF2 CharStrings, and allowed avoiding referencing the width fields. I worked around this by providing dummy values for the Private.nominalWidthX and defaultWidthX.
Added a public method PrivateDict.in_cff2.
Fix syntax error reported by build system: can't mix string string types when doing literal concatenation
Fix local import reference - doesn't work in Python3.
Addressed issues raised by @msousa for PR 1345 yesterday.
Will change cff2_merge_funcs.py and cff2mergePen.py from tab to space indentations after the current comments are resolved.
Add various improvements from comments:
- do not edit the post table under varLib.build(). Setting post table format 2 or 3 is now expected to be managed by whatever calls varLib.build().
- In the t2CharStringPen module, rename closure _round() nested in makeRoundFunc to an exportable function, and use it in cff2mergePen.
- remove TypeSupply copyright from cff2mergePen.
- use modulo function to convert float to int when it is meant to be 0 in cff2mergePen.
cff2_merge_funcs.py:merge_PrivateDicts() should only be blending the hint related fields in the PrivateDict. This oversight that was surfaced by @madig reporting an error building his Cantrell font. The bug appeared when the font was subroutinized, as the pen draw method then has to interpret the Subr field in order to access T2Charstring subroutines.
Fix expected ttx output file. When I removed the logic to add glyph names to the post table, glyph names in the ttx file changed.
Miguel prefers a simple list for readability in cff2_merge_funs.py:138.
I'm also unimpressed by the copy-pasted bounds logic in hhea and vhea,
and the fact that that's coded in there instead of calling a function
on CFF / glyf tables respectively.
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
There can only be one TopDict in an OpenType font, whether CFF or CFF2;
plus in the latter, TopDict INDEX and Names INDEX are gone, just the
one TopDict is left. Most of the time, one simple wants to get to
that single TopDict instance.
So instead of doing this:
topDict = font['CFF '].cff.values()[0]
one can alternatively do this now:
topDict = font['CFF '].cff[0]
* Removed `CFFContext`
* Added `isCFF2` argument to CFFFontSet.decompile/compile, used from
respective ttLib classes
* Index classes get a `isCFF2` argument in constructor (used for
decompiling); must be True/False if `file` argument is not None;
it is stored as self._isCFF2 to support lazy loading
* Removed `TopDictData` class; reuse same `TopDictIndexCompiler` for
both CFF and CFF2
* `CFFWriter` and all `*Compiler` classes get an `isCFF2` argument;
defaults to the parent compiler's `isCFF2` attribute
* Removed `size` argument from `produceItem` method as unused and
useless (`len(data)` is the same)
* psCharStrings: removed useless ByteCodeBase class
* A reference to the TopDict's VarStoreData is passed down to all
the FontDicts' PrivateDict, so it can be used to get the number of
regions while decompiling blend and vsindex operators
See dicussion:
https://github.com/fonttools/fonttools/pull/968#issuecomment-309920007
