* sfnt/ttcolr.c (tt_face_get_colr_glyph_paint,
tt_face_get_colorline_stops, tt_face_get_paint): Additional checks
for whether colr table is present. Prevents crashes when these
methods are called on non-COLR fonts.
* include/freetype/config/ftoption.h (TT_SUPPORT_COLRV1): New macro
so that clients can test whether the FreeType checkout that they are
building against supports the 'COLR' v1 API. This is intended to be
a temporary solution until 'COLR' v1 support is released in a
FreeType version and such a check can be made by using the version
number instead.
* src/base/ftobjs.c (FT_Get_Color_Glyph_Paint, FT_Get_Paint_Layers,
FT_Get_Paint, FT_Get_Colorline_Stops): Add basic sanity checks,
check for existence of `FT_Face`, check arguments and delegate calls
for the respective 'COLR' v1 API to the SFNT driver.
* include/freetype/internal/sfnt.h (TT_Get_Color_Glyph_Paint_Func,
TT_Get_Paint_Layers_Func, TT_Get_Colorline_Stops_Func,
TT_Get_Paint_Func): New function pointer types.
(SFNT_Interface): Add them.
(FT_DEFINE_SFNT_INTERFACE): Updated.
* src/sfnt/sfdriver.c (PUT_COLOR_LAYERS_V1): New macro.
(sfnt_interface): Add new function pointers.
* src/sfnt/ttcolr.c (tt_face_get_paint_layers): New function to get
the layers of a `PaintColrLayers` table in the font, using an
`FT_LayerIterator` from an `FT_PaintColrLayers` object retrieved via
`tt_face_get_paint`.
* src/sfnt/ttcolr.h: Updated.
* src/sfnt/ttcolr.c (tt_face_get_colorline_stops): New function to
return the current `FT_ColorStop` object from `FT_ColorStopIterator`.
Also increment the iterator.
* src/sfnt/ttcolr.h: Updated.
* src/sfnt/ttcolr.c (tt_face_get_paint): New function to resolve an
`FT_OpaquePaint` paint reference into an `FT_COLR_Paint` object of a
certain format, which contains the detailed information stored in a
paint of the respective format.
(read_paint): New function to provide the format specific parsing
and to populate the data members of each specific `FT_COLR_Paint`
subtype.
(read_color_line): New function to parse retrieved color line
information into an `FT_ColorLine` object, which has information
about the color line extend mode as well as an
`FT_ColorStopIterator` object.
* src/sfnt/ttcolr.h: Updated.
* src/sfnt/ttcolr.c (BaseGlyphV1Record): New structure.
(tt_face_load_colr): Handle version 1 table header.
(find_base_glyph_v1_record): New auxiliary function.
(tt_face_get_colr_glyph_paint): New function to find the root
`FT_OpaquePaint` object for a given glyph ID.
* src/sfnt/ttcolr.h: Updated.
* include/freetype/freetype.h (FT_Get_Color_Glyph_Paint): New method
for retrieving the root paint object for a color glyph by specifying
a glyph ID.
(FT_Get_Paint_Layers): New method for retrieving the layers of a
`PaintColorGlyph`.
(FT_Get_ColorLine_Stops): New method for retrieving the stops of a
color.
(FT_Get_Paint): New method for resolving an `FT_OpaquePaint` into an
`FT_COLR_Paint` object.
* include/freetype/freetype.h (FT_PaintFormat, FT_ColorStopIterator,
FT_ColorIndex, FT_ColorStop, FT_PaintExtend, FT_ColorLine,
FT_Affine23, FT_CompositeMode, FT_OpaquePaint, FT_PaintColrLayers,
FT_PaintSolid, FT_PaintLinearGradient, FT_PaintRadialGradient,
FT_PaintGlyph, FT_PaintColrGlyph, FT_PaintTransformed,
FT_PaintTranslate, FT_PaintRotate, FT_PaintSkew, FT_PaintComposite,
FT_COLR_Paint): Adding structs and enum to represent paint format,
color stop information, gradient extend information, structs to
reference paint offsets, and to define transforms and compositions.
Adding a union type to represent the union of the structs,
distinguished by `FT_PaintFormat`.
