Fixes https://bugs.chromium.org/p/skia/issues/detail?id=14021
* src/sfnt/ttcolr.c (VAR_IDX_BASE_SIZE): New macro.
(tt_face_get_colorline_stops): Fix off-by-one bounds check calculation, take
`VarColorStop` into account, and hopefully make it easier to read.
* src/sfnt/ttcolr.c (read_paint): Add `colr` argument, necessary for...
... another use of `ENSURE_READ_BYTES`.
Update callers.
(tt_face_get_paint_layers): Ensure that the 4-byte paint table
offset can be read.
This is a follow-up to !124 and issue
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=52404
* src/sfnt/ttcolr.c (ENSURE_READ_BYTES): New macro.
(read_paint): Use it – after the start pointer `p` has been checked for
whether it allows reading the format byte, each successive paint table field
read need to be bounds-checked before reading further values.
Reported as
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=52404
* src/sfnt/ttcolr.c (tt_face_load_colr): If the version is determined to
be 1, then the table size has to be at least the size of the v1 header.
Also, for peeking the number of base glyphs and entries in the layer list,
ensure that the table is sufficiently long.
Fixes#1179. Original patch by Sergey Temnikov.
Fixes#1178.
* src/sfnt/ttcolr.c (get_deltas_for_var_index_base): Set outer index to
0 and inner index to the delta index when retrieving deltas if the
`COLR` table has no delta set index map.
* 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.
* src/sfnt/ttcolr.c (FT_PaintFormat_Internal): New enumeration values
`FT_COLR_PAINTFORMAT_INTERNAL_VAR_ROTATE` and
`FT_COLR_PAINTFORMAT_INTERNAL_VAR_ROTATE_CENTER`.
(read_paint): Handle new enumeration values.
* src/sfnt/ttcolr.c (FT_PaintFormat_Internal): New enumeration value
`FT_COLR_PAINTFORMAT_INTERNAL_VAR_TRANSLATE`.
(read_paint): Handle new enumeration value.
* src/sfnt/ttcolr.c (FT_PaintFormat_Internal): New enumeration value
`FT_COLR_PAINTFORMAT_INTERNAL_VAR_TRANSFORM`.
(read_paint): Handle new enumeration value.
* src/sfnt/ttcolr.c (read_paint) [TT_CONFIG_OPTION_GX_VAR_SUPPORT]: Read and
apply deltas to radial, linear, and sweep gradient coordinates such as 'p0',
'p1', 'p2', 'center', 'radii', and 'angles'.
* include/freetype/ftcolor.h (FT_ColorStopIterator): Add field
`read_variable` to indicate whether a variation index base should be read.
* src/sfnt/ttcolr.c: (FT_PaintFormat_Internal): New enumerations
`FT_COLR_PAINTFORMAT_INTERNAL_VAR_LINEAR_GRADIENT`
`FT_COLR_PAINTFORMAT_INTERNAL_VAR_RADIAL_GRADIENT`, and
`FT_COLR_PAINTFORMAT_INTERNAL_VAR_SWEEP_GRADIENT`.
(read_color_line): New parameter `read_variable`; update callers.
(read_paint): Handle new enumerations.
* src/sfnt/ttcolr.c (FT_PaintFormat_Internal_): New enumeration
`FT_COLR_PAINTFORMAT_INTERNAL_VAR_SOLID`.
(get_deltas_for_var_index_base) [TT_CONFIG_OPTION_GX_VAR_SUPPORT]: New
function to retrieve an array of delta values, which will be used for most
of 'COLR' v1 variation formats (in follow-up commits).
(read_paint): Add `face` parameter; update caller.
Handle `FT_COLR_PAINTFORMAT_INTERNAL_VAR_SOLID`.
* src/sfnt/ttcolr.c: Include `ttobjs.h` temporarily.
(VARIABLE_COLRV1_ENABLED): New temporary macro to detect whether variable
COLRv1 is enabled.
(Colr): New fields `var_store` and `delta_set_idx_map`.
(tt_face_load_colr, tt_face_free_colr) [VARIABLE_COLRV1_ENABLED]: Load and
free variation store data using the functions from the Multiple Masters
service.
The optional 'COLR' v1 glyph-specific clip box helps upstream graphics
libraries allocate a sufficiently large bitmap for a glyph without having to
traverse the glyph graph for that. See
https://github.com/googlefonts/colr-gradients-spec/issues/251
for background on the introduction of this specification change.
* include/freetype/ftcolor.h (FT_ClipBox): New structure.
(FT_Get_Color_Glyph_ClipBox): New function declaration.
* include/freetype/internal/sfnt.h (TT_Get_Color_Glyph_ClipBox_Func):
New function type.
(SFNT_Interface, FT_DEFINE_SFNT_INTERFACE): Use it.
* src/base/ftobjs.c (FT_Get_Color_Glyph_ClipBox): New function to link API
with SFNT implementation.
* src/sfnt/sfdriver.c (sfnt_interface): Updated.
* src/sfnt/ttcolr.c (Colr): New field `clip_list`.
(tt_face_load_colr): Parse global clip list offset.
(tt_face_get_color_glyph_clipbox): New function to find the clip box for a
glyph id from the clip list array.
* src/sfnt/ttcolr.h: Updated.
* src/sfnt/ttcolr.c (read_paint): PaintSweepGradient follows other
spec changes and now has the angles specified as F2DOT14, reflect
that in the implementation.
* include/freetype/ftcolor.h (FT_PaintSweepGradient): Update
documentation.
* src/sfnt/ttcolr.c (read_paint): Implement spec change where
affine transform matrix is now referenced by offset instead of
being placed inline in the PaintTransform table.
* src/sfnt/ttcolr.c (read_paint): Implement spec changes around
PaintSkew, PaintSkewAroundCenter. Update parsing to read shorter
values as changed in the spec.
* include/freetype/ftcolor.h (FT_PaintSkew): Update documentation.
* src/sfnt/ttcolr.c (read_paint): Implement spec change where
PaintRotate and PaintRotateAroundCenter were split for a more
compact format definition. Update parsing to read shorter values
as changed in the spec.
* include/freetype/ftcolor.h (FT_PaintRotate): Update documentation.
'COLR' v1 fonts do not necessarily need to have a layer list; for
this reason, 'fontTools' recently started generating fonts in a way
that drops the layer list if there are no layers in it. This
results in the layer list offset becoming zero, which FreeType
treated as an invalid table. Fix that and handle the case for layer
list offset being 0. This slightly changes how we need to calculate
the starting offset for paints.
* src/sfnt/ttcolr.c (tt_face_load_colr): Handle case of layer list
offset being zero without outright rejecting table.
Paint tables can appear before the `base_glyphs_v1` offset if the
font is produced with the layer list before the base glyph list. In
this case paint tables can occur after the layer list but before the
base glyph list. Checks in the 'COLR' v1 code were rejecting fonts
with this layout. Improve these checks by calculating a minimum
offset after which paint tables can occur and use that in safety
checks.
* src/sfnt/ttcolr.c (Colr, tt_face_load_colr): Declare
`paint_start_v1` and calculate that as the minimum of the end of
layer list and base glyph list.
(get_child_table_pointer, read_paint, tt_face_get_paint_layers):
Use that in safety checks.
* include/freetype/ftcolor.h (FT_PaintTransformed, FT_PaintFormat,
FT_COLR_Paint): Do it to make it harmonize with other names such as
'PaintTranslate'.
* src/sfnt/ttcolr.c (read_paint, tt_face_get_paint): Ditto.
Werner Lemberg