|
b04db387
|
2025-07-04T19:52:53
|
|
[sfnt] Rewrite GPOS kerning support. (2/2)
The previous code had a fundamental flaw: it didn't validate the necessary
parts of the 'GPOS' table before accessing it, causing crashes with
malformed data (since `TT_CONFIG_OPTION_GPOS_KERNING` is off by default,
standard fuzzers don't catch these problems). Additionally, it did a lot of
parsing while accessing kerning data, making it rather slow.
The new implementation fixes this. After validation, offsets to the 'GPOS'
lookup subtables used in the 'kern' feature that correspond to 'simple'
kerning (i.e., similar to 'kern' table kerning) are stored in `TT_Face`;
this greatly simplifies and accelerates access to the kerning data.
Testing with font `SF-Pro.ttf` version '1.00', the validation time for the
'GPOS' table increases the start-up time of `FT_New_Face` by less than 1%,
while calls to `FT_Get_Kerning` become about 3.5 times faster.
* include/freetype/internal (gpos_kerning_available): Replace with...
(gpos_lookups_kerning, num_gpos_lookups_kerning): ... these new fields.
Update callers.
* src/ttgpos.c [TT_CONFIG_OPTION_GPOS_KERNING]: A new implementation.
|
|
|
8ef26a80
|
2025-07-04T19:50:48
|
|
[sfnt] Rewrite GPOS kerning support. (1/2)
This commit removes the previous implementation.
|
|
|
7f559fbe
|
2025-06-10T04:55:43
|
|
Update links.
Found with `linkchecker --check-extern index.html` running locally in the
'freetype-web' repository.
|
|
|
6b992aaa
|
2024-08-11T19:44:13
|
|
* src/*/*: Fix C++ compilation; fix clang warnings.
|
|
4f0256c1
|
2024-01-27T10:47:10
|
|
* src/sfnt/ttgpos.c (tt_gpos_get_glyph_class): Fix warning C4018.
|
|
8f286c86
|
2024-01-19T16:42:48
|
|
Add support for kerning from 'GPOS' tables.
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.
|