diff options
author | Dominik Röttsches <drott@chromium.org> | 2020-12-16 16:14:19 +0200 |
---|---|---|
committer | Werner Lemberg <wl@gnu.org> | 2021-01-14 15:50:37 +0100 |
commit | 08dba4dc3555cbb90c7be59a31c413c26cfba503 (patch) | |
tree | 8e6a04da391998a44091b8130f8373e31cf8c097 /include/freetype/freetype.h | |
parent | f57c24db63be5abca29108c5df7cbb170fd517af (diff) | |
download | freetype2-08dba4dc3555cbb90c7be59a31c413c26cfba503.tar.gz |
Add new methods required for 'COLR' v1 to public API (#59703).
* 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.
Diffstat (limited to 'include/freetype/freetype.h')
-rw-r--r-- | include/freetype/freetype.h | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/include/freetype/freetype.h b/include/freetype/freetype.h index 591377e45..93cc9b16e 100644 --- a/include/freetype/freetype.h +++ b/include/freetype/freetype.h @@ -4881,6 +4881,165 @@ FT_BEGIN_HEADER /************************************************************************** * + * @function: + * FT_Get_Color_Glyph_Paint + * + * @description: + * This is the starting point and interface to color gradient + * information in a 'COLR' v1 table in OpenType fonts to recursively + * retrieve the paint tables for the directed acyclic graph of a colored + * glyph, given a glyph ID. + * + * https://github.com/googlefonts/colr-gradients-spec + * + * In a 'COLR' v1 font, each color glyph defines a directed acyclic + * graph of nested paint tables, such as `PaintGlyph`, `PaintSolid`, + * `PaintLinearGradient`, `PaintRadialGradient`, and so on. Using this + * function and specifying a glyph ID, one retrieves the root paint + * table for this glyph ID. + * + * @input: + * face :: + * A handle to the parent face object. + * + * base_glyph :: + * The glyph index for which to retrieve the root paint table. + * + * @output: + * paint :: + * The @FT_OpaquePaint object that references the actual paint table. + * + * The respective actual @FT_COLR_Paint object is retrieved via + * @FT_Get_Paint. + * + * @return: + * Value~1 if everything is OK. If no color glyph is found, or the root + * paint could not be retrieved, value~0 gets returned. In case of an + * error, value~0 is returned also. + */ + FT_EXPORT( FT_Bool ) + FT_Get_Color_Glyph_Paint( FT_Face face, + FT_UInt base_glyph, + FT_OpaquePaint* paint ); + + + /************************************************************************** + * + * @function: + * FT_Get_Paint_Layers + * + * @description: + * Access the layers of a `PaintColrLayers` table. + * + * If the root paint of a color glyph, or a nested paint of a 'COLR' + * glyph is a `PaintColrLayers` table, this function retrieves the + * layers of the `PaintColrLayers` table. + * + * The @FT_PaintColrLayers object contains an @FT_LayerIterator, which + * is used here to iterate over the layers. Each layer is returned as + * an @FT_OpaquePaint object, which then can be used with @FT_Get_Paint + * to retrieve the actual paint object. + * + * @input: + * face :: + * A handle to the parent face object. + * + * @inout: + * iterator :: + * The @FT_LayerIterator from an @FT_PaintColrLayers object, for which + * the layers are to be retrieved. The internal state of the iterator + * is incremented after one call to this function for retrieving one + * layer. + * + * @output: + * paint :: + * The @FT_OpaquePaint object that references the actual paint table. + * The respective actual @FT_COLR_Paint object is retrieved via + * @FT_Get_Paint. + * + * @return: + * Value~1 if everything is OK. Value~0 gets returned when the paint + * object can not be retrieved or any other error occurs. + */ + FT_EXPORT( FT_Bool ) + FT_Get_Paint_Layers( FT_Face face, + FT_LayerIterator* iterator, + FT_OpaquePaint* paint ); + + + /************************************************************************** + * + * @function: + * FT_Get_Colorline_Stops + * + * @description: + * This is an interface to color gradient information in a 'COLR' v1 + * table in OpenType fonts to iteratively retrieve the gradient and + * solid fill information for colored glyph layers for a specified glyph + * ID. + * + * https://github.com/googlefonts/colr-gradients-spec + * + * @input: + * face :: + * A handle to the parent face object. + * + * @inout: + * iterator :: + * The retrieved @FT_ColorStopIterator, configured on an @FT_ColorLine, + * which in turn got retrieved via paint information in + * @FT_PaintLinearGradient or @FT_PaintRadialGradient. + * + * @output: + * color_stop :: + * Color index and alpha value for the retrieved color stop. + * + * @return: + * Value~1 if everything is OK. If there are no more color stops, + * value~0 gets returned. In case of an error, value~0 is returned + * also. + */ + FT_EXPORT( FT_Bool ) + FT_Get_Colorline_Stops( FT_Face face, + FT_ColorStop* color_stop, + FT_ColorStopIterator* iterator ); + + + /************************************************************************** + * + * @function: + * FT_Get_Paint + * + * @description: + * Access the details of a paint using an @FT_OpaquePaint opaque paint + * object, which internally stores the offset to the respective `Paint` + * object in the 'COLR' table. + * + * @input: + * face :: + * A handle to the parent face object. + * + * opaque_paint :: + * The opaque paint object for which the underlying @FT_COLR_Paint + * data is to be retrieved. + * + * @output: + * paint :: + * The specific @FT_COLR_Paint object containing information coming + * from one of the font's `Paint*` tables. + * + * @return: + * Value~1 if everything is OK. Value~0 if no details can be found for + * this paint or any other error occured. + */ + FT_EXPORT( FT_Bool ) + FT_Get_Paint( FT_Face face, + FT_OpaquePaint opaque_paint, + FT_COLR_Paint* paint ); + + + /************************************************************************** + * * @section: * base_interface * |