This commit adds support for kerning from 'GPOS' tables, while maintaining
support for basic 'kern' tables. `FT_HAS_KERNING` will be true for a font
with either available and `FT_Get_Kerning` will still use the basic 'kern'
table data if avilable, otherwise check the GPOS 'kern' feature.
This feature is disabled by default; it can be enabled with the
`TT_CONFIG_OPTION_GPOS_KERNING` flag.
Only basic kerning (pair positioning with just an x advance) is supported
from the GPOS layout features; support for that was added to make the
existing `FT_Get_Kerning` API more consistently functional. FreeType does
not intend to extend itself to further GPOS functionality though; a
higher-level library like HarfBuzz can be used instead for that.
* include/freetype/config/ftoption.h, include/devel/ftoption.h
(TT_CONFIG_OPTION_GPOS_KERNING): New configuration option.
* include/freetype/internal/fttrace.h: Add `ttgpos` trace handler.
* include/freetype/internal/sfnt.h (SFNT_Interface): Add `load_gpos` and
`get_gpos_kerning` fields.
(FT_DEFINE_SFNT_INTERFACE): Updated.
* include/freetype/internal/tttypes.h: Include `fttypes.h`.
(TT_FaceRec) [TT_CONFIG_OPTION_GPOS_KERNING]: Add `gpos_table` and
`gpos_kerning_available` fields.
* src/sfnt/ttgpos.c, src/sfnt/ttgpos.h: New files.
* src/sfnt/sfdriver.c [TT_CONFIG_OPTION_GPOS_KERNING]: Include `ttgpos.h`.
(sfnt_interface): Updated.
* src/sfnt/sfnt.c: Include `ttgpos.c`.
* src/sfnt/sfobjs.c [TT_CONFIG_OPTION_GPOS_KERNING]: Include `ttgpos.h`.
(sfnt_load_face) [TT_CONFIG_OPTION_GPOS_KERNING]: Load and free GPOS kerning
data; check GPOS kerning availability.
* src/truetype/ttdriver.c (tt_get_kerning): Use GPOS kerning if there's no
'kern' table.
Remove Infinality as an option before its complete extraction.
* include/freetype/ftoption.h: Remove the Infinality option.
* devel/ftoption.h: Ditto.
* include/freetype/ftdriver.h (TT_INTERPRETER_VERSION_38): Is 40 now.
This is mandated by the C99 standard, and clang 15 produces zillions of
warnings otherwise.
* devel/ftoption.h, include/freetype/config/ftoption.h,
include/freetype/internal/ftmemory.h, src/autofit/afhints.h,
src/autofit/afmodule.c, src/autofit/aftypes.h, src/base/ftadvanc.c,
src/base/ftdbgmem.c, src/base/ftstream.c, src/bdf/bdflib.c,
src/truetype/ttinterp.c: Replace identifiers of the form `_foo` with `foo_`.
This gives users a possibility to deactivate new features not (yet) in the
OpenType standard.
* include/freetype/config/ftoption.h, devel/ftoption.h
(TT_CONFIG_OPTION_NO_BORING_EXPANSION): New macro.
* src/truetype/ttgxvar.c (ft_var_load_avar): Use it to disable 'avar'
version 2.0 support.
* src/sfnt/ttcolr.c (FT_PaintFormat_Internal): New enumeration values
`FT_COLR_PAINTFORMAT_INTERNAL_VAR_SKEW`,
`FT_COLR_PAINTFORMAT_INTERNAL_SKEW_CENTER`, and
`FT_COLR_PAINTFORMAT_INTERNAL_VAR_SKEW_CENTER`.
(read_paint): Handle new enumeration values.
Alexei Podtelezhnikov
David Saltzman
Werner Lemberg
Dominik Röttsches