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Add types required for 'COLR' v1 to public API (#59703).

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* 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`.
This commit is contained in:
Dominik Röttsches 2020-12-16 16:02:02 +02:00 committed by Werner Lemberg
parent 03ceda9701
commit f57c24db63
2 changed files with 677 additions and 1 deletions
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16
ChangeLog
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@ -1,3 +1,19 @@
2020-12-16 Dominik Röttsches <drott@chromium.org>
Add types required for 'COLR' v1 to public API (#59703).
* 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`.
2021-01-10 Werner Lemberg <wl@gnu.org>
* builds/*: s/BUILD_DIR/PLATFORM_DIR/.

662
include/freetype/freetype.h
View File

@ -2902,7 +2902,7 @@ FT_BEGIN_HEADER
*
* If the font is 'tricky' (see @FT_FACE_FLAG_TRICKY for more), using
* `FT_LOAD_NO_SCALE` usually yields meaningless outlines because the
* subglyphs must be scaled and positioned with hinting instructions.
* subglyphs must be scaled and positioned with hinting instructions.
* This can be solved by loading the font without `FT_LOAD_NO_SCALE`
* and setting the character size to `font->units_per_EM`.
*
@ -4219,6 +4219,666 @@ FT_BEGIN_HEADER
FT_LayerIterator* iterator );
/**************************************************************************
*
* @enum:
* FT_PaintFormat
*
* @description:
* Enumeration describing the different gradient types of the v1
* extensions to the 'COLR' table, see
* 'https://github.com/googlefonts/colr-gradients-spec'.
*/
typedef enum FT_PaintFormat_
{
FT_COLR_PAINTFORMAT_COLR_LAYERS = 1,
FT_COLR_PAINTFORMAT_SOLID = 2,
FT_COLR_PAINTFORMAT_LINEAR_GRADIENT = 3,
FT_COLR_PAINTFORMAT_RADIAL_GRADIENT = 4,
FT_COLR_PAINTFORMAT_GLYPH = 5,
FT_COLR_PAINTFORMAT_COLR_GLYPH = 6,
FT_COLR_PAINTFORMAT_TRANSFORMED = 7,
FT_COLR_PAINTFORMAT_TRANSLATE = 8,
FT_COLR_PAINTFORMAT_ROTATE = 9,
FT_COLR_PAINTFORMAT_SKEW = 10,
FT_COLR_PAINTFORMAT_COMPOSITE = 11,
FT_COLR_PAINT_FORMAT_MAX = 12,
FT_COLR_PAINTFORMAT_UNSUPPORTED = 255
} FT_PaintFormat;
/**************************************************************************
*
* @struct:
* FT_ColorStopIterator
*
* @description:
* This iterator object is needed for @FT_Get_Colorline_Stops. It keeps
* state while iterating over the stops of an @FT_ColorLine,
* representing the `ColorLine` struct of the v1 extensions to 'COLR',
* see 'https://github.com/googlefonts/colr-gradients-spec'.
*
* @fields:
* num_color_stops ::
* The number of color stops for the requested glyph index. Set by
* @FT_Get_Colorline_Stops.
*
* current_color_stop ::
* The current color stop. Set by @FT_Get_Colorline_Stops.
*
* p ::
* An opaque pointer into 'COLR' table data. The caller must set this
* to `NULL` before the first call of @FT_Get_Colorline_Stops.
*/
typedef struct FT_ColorStopIterator_
{
FT_UInt num_color_stops;
FT_UInt current_color_stop;
FT_Byte* p;
} FT_ColorStopIterator;
/**************************************************************************
*
* @struct:
* FT_ColorIndex
*
* @description:
* A structure representing a `ColorIndex` value of the 'COLR' v1
* extensions, see 'https://github.com/googlefonts/colr-gradients-spec'.
*
* @fields:
* palette_index ::
* The palette index into a 'CPAL' palette.
*
* alpha ::
* Alpha transparency value multiplied with the value from 'CPAL'.
*/
typedef struct FT_ColorIndex_
{
FT_UInt16 palette_index;
FT_F2Dot14 alpha;
} FT_ColorIndex;
/**************************************************************************
*
* @struct:
* FT_ColorStop
*
* @description:
* A structure representing a `ColorStop` value of the 'COLR' v1
* extensions, see 'https://github.com/googlefonts/colr-gradients-spec'.
*
* @fields:
* stop_offset ::
* The stop offset between 0 and 1 along the gradient.
*
* color ::
* The color information for this stop, see @FT_ColorIndex.
*/
typedef struct FT_ColorStop_
{
FT_F2Dot14 stop_offset;
FT_ColorIndex color;
} FT_ColorStop;
/**************************************************************************
*
* @enum:
* FT_PaintExtend
*
* @description:
* An enumeration representing the 'Extend' mode of the 'COLR' v1
* extensions, see 'https://github.com/googlefonts/colr-gradients-spec'.
* It describes how the gradient fill continues at the other boundaries.
*/
typedef enum FT_PaintExtend_
{
FT_COLR_PAINT_EXTEND_PAD = 0,
FT_COLR_PAINT_EXTEND_REPEAT = 1,
FT_COLR_PAINT_EXTEND_REFLECT = 2
} FT_PaintExtend;
/**************************************************************************
*
* @struct:
* FT_ColorLine
*
* @description:
* A structure representing a `ColorLine` value of the 'COLR' v1
* extensions, see 'https://github.com/googlefonts/colr-gradients-spec'.
* It describes a list of color stops along the defined gradient.
*
* @fields:
* extend ::
* The extend mode at the outer boundaries, see @FT_PaintExtend.
*
* color_stop_iterator ::
* The @FT_ColorStopIterator used to enumerate and retrieve the
* actual @FT_ColorStop's.
*/
typedef struct FT_ColorLine_
{
FT_PaintExtend extend;
FT_ColorStopIterator color_stop_iterator;
} FT_ColorLine;
/**************************************************************************
*
* @struct:
* FT_Affine23
*
* @description:
* A structure used to store a 2x3 matrix. Coefficients are in
* 16.16 fixed-point format. The computation performed is
*
* ```
* x' = x*xx + y*xy + dx
* y' = x*yx + y*yy + dy
* ```
*
* @fields:
* xx ::
* Matrix coefficient.
*
* xy ::
* Matrix coefficient.
*
* dx ::
* x translation.
*
* yx ::
* Matrix coefficient.
*
* yy ::
* Matrix coefficient.
*
* dy ::
* y translation.
*
*/
typedef struct FT_Affine_23_
{
FT_Fixed xx, xy, dx;
FT_Fixed yx, yy, dy;
} FT_Affine23;
/**************************************************************************
*
* @enum:
* FT_Composite_Mode
*
* @description:
* An enumeration listing the 'COLR' v1 composite modes used in
* @FT_PaintComposite. For more details on each paint mode, see
* 'https://www.w3.org/TR/compositing-1/#porterduffcompositingoperators'.
*/
typedef enum FT_Composite_Mode_
{
FT_COLR_COMPOSITE_CLEAR = 0,
FT_COLR_COMPOSITE_SRC = 1,
FT_COLR_COMPOSITE_DEST = 2,
FT_COLR_COMPOSITE_SRC_OVER = 3,
FT_COLR_COMPOSITE_DEST_OVER = 4,
FT_COLR_COMPOSITE_SRC_IN = 5,
FT_COLR_COMPOSITE_DEST_IN = 6,
FT_COLR_COMPOSITE_SRC_OUT = 7,
FT_COLR_COMPOSITE_DEST_OUT = 8,
FT_COLR_COMPOSITE_SRC_ATOP = 9,
FT_COLR_COMPOSITE_DEST_ATOP = 10,
FT_COLR_COMPOSITE_XOR = 11,
FT_COLR_COMPOSITE_SCREEN = 12,
FT_COLR_COMPOSITE_OVERLAY = 13,
FT_COLR_COMPOSITE_DARKEN = 14,
FT_COLR_COMPOSITE_LIGHTEN = 15,
FT_COLR_COMPOSITE_COLOR_DODGE = 16,
FT_COLR_COMPOSITE_COLOR_BURN = 17,
FT_COLR_COMPOSITE_HARD_LIGHT = 18,
FT_COLR_COMPOSITE_SOFT_LIGHT = 19,
FT_COLR_COMPOSITE_DIFFERENCE = 20,
FT_COLR_COMPOSITE_EXCLUSION = 21,
FT_COLR_COMPOSITE_MULTIPLY = 22,
FT_COLR_COMPOSITE_HSL_HUE = 23,
FT_COLR_COMPOSITE_HSL_SATURATION = 24,
FT_COLR_COMPOSITE_HSL_COLOR = 25,
FT_COLR_COMPOSITE_HSL_LUMINOSITY = 26,
FT_COLR_COMPOSITE_MAX = 27
} FT_Composite_Mode;
/**************************************************************************
*
* @struct:
* FT_OpaquePaint
*
* @description:
* A structure representing an offset to a `Paint` value stored in any
* of the paint tables of a 'COLR' v1 font. Compare Offset<24> there.
* When 'COLR' v1 paint tables represented by FreeType objects such as
* @FT_PaintColrLayers, @FT_PaintComposite, or @FT_PaintTransformed
* reference downstream nested paint tables, we do not immediately
* retrieve them but encapsulate their location in this type. Use
* @FT_Get_Paint to retrieve the actual @FT_COLR_Paint object that
* describes the details of the respective paint table.
*
* @fields:
* p ::
* An internal offset to a Paint table, needs to be set to NULL before
* passing this struct as an argument to @FT_Get_Paint.
*/
typedef struct FT_Opaque_Paint_
{
FT_Byte* p;
} FT_OpaquePaint;
/**************************************************************************
*
* @struct:
* FT_PaintColrLayers
*
* @description:
* A structure representing a `PaintColrLayers` table of a 'COLR' v1
* font. This table describes a set of layers that are to be composited
* with composite mode `FT_COLR_COMPOSITE_SRC_OVER`. The return value
* of this function is an @FT_LayerIterator initialized so that it can
* be used with @FT_Get_Paint_Layers to retrieve the @FT_OpaquePaint
* objects as references to each layer.
*
* @fields:
* layer_iterator ::
* The layer iterator that describes the layers of this paint.
*/
typedef struct FT_PaintColrLayers_
{
FT_LayerIterator layer_iterator;
} FT_PaintColrLayers;
/**************************************************************************
*
* @struct:
* FT_PaintSolid
*
* @description:
* A structure representing a `PaintSolid` value of the 'COLR' v1
* extensions, see 'https://github.com/googlefonts/colr-gradients-spec'.
* Using a `PaintSolid` value means that the glyph layer filled with
* this paint is solid-colored and does not contain a gradient.
*
* @fields:
* color ::
* The color information for this solid paint, see @FT_ColorIndex.
*/
typedef struct FT_PaintSolid_
{
FT_ColorIndex color;
} FT_PaintSolid;
/**************************************************************************
*
* @struct:
* FT_PaintLinearGradient
*
* @description:
* A structure representing a `PaintLinearGradient` value of the 'COLR'
* v1 extensions, see
* 'https://github.com/googlefonts/colr-gradients-spec'. The glyph
* layer filled with this paint is drawn filled with a linear gradient.
*
* @fields:
* colorline ::
* The @FT_ColorLine information for this paint, i.e., the list of
* color stops along the gradient.
*
* p0 ::
* The starting point of the gradient definition (in font units).
*
* p1 ::
* The end point of the gradient definition (in font units).
*
* p2 ::
* Optional point~p2 to rotate the gradient (in font units).
* Otherwise equal to~p0.
*/
typedef struct FT_PaintLinearGradient_
{
FT_ColorLine colorline;
/* TODO: Potentially expose those as x0, y0 etc. */
FT_Vector p0;
FT_Vector p1;
FT_Vector p2;
} FT_PaintLinearGradient;
/**************************************************************************
*
* @struct:
* FT_PaintRadialGradient
*
* @description:
* A structure representing a `PaintRadialGradient` value of the 'COLR'
* v1 extensions, see
* 'https://github.com/googlefonts/colr-gradients-spec'. The glyph
* layer filled with this paint is drawn filled filled with a radial
* gradient.
*
* @fields:
* colorline ::
* The @FT_ColorLine information for this paint, i.e., the list of
* color stops along the gradient.
*
* c0 ::
* The center of the starting point of the radial gradient (in font
* units).
*
* r0 ::
* The radius of the starting circle of the radial gradient (in font
* units).
*
* c1 ::
* The center of the end point of the radial gradient (in font units).
*
* r1 ::
* The radius of the end circle of the radial gradient (in font
* units).
*/
typedef struct FT_PaintRadialGradient_
{
FT_ColorLine colorline;
/* TODO: Potentially expose those as x0, y0 etc. */
FT_Vector c0;
FT_UShort r0;
FT_Vector c1;
FT_UShort r1;
} FT_PaintRadialGradient;
/**************************************************************************
*
* @struct:
* FT_PaintGlyph
*
* @description:
* A structure representing a 'COLR' v1 `PaintGlyph` paint table.
*
* @fields:
* paint ::
* An opaque paint object pointing to a `Paint` table that serves as
* the fill for the glyph ID.
*
* glyphID ::
* The glyph ID from the 'glyf' table, which serves as the contour
* information that is filled with paint.
*
*/
typedef struct FT_PaintGlyph_
{
FT_OpaquePaint paint;
FT_UInt glyphID;
} FT_PaintGlyph;
/**************************************************************************
*
* @struct:
* FT_PaintColrGlyph
*
* @description:
* A structure representing a 'COLR' v1 `PaintColorGlyph` paint table.
*
* @fields:
* glyphID ::
* The glyph ID from the `BaseGlyphV1List` table that is drawn for
* this paint.
*/
typedef struct FT_PaintColrGlyph_
{
FT_UInt glyphID;
} FT_PaintColrGlyph;
/**************************************************************************
*
* @struct:
* FT_PaintTransformed
*
* @description:
* A structure representing a 'COLR' v1 `PaintTransformed` paint table.
*
* @fields:
* paint ::
* An opaque paint that is subject to being transformed.
*
* affine ::
* A 2x3 transformation matrix in @FT_Affine23 format.
*/
typedef struct FT_PaintTransformed_
{
FT_OpaquePaint paint;
FT_Affine23 affine;
} FT_PaintTransformed;
/**************************************************************************
*
* @struct:
* FT_PaintTranslate
*
* @description:
* A structure representing a 'COLR' v1 `PaintTranslate` paint table.
* Used for translating downstream paints by a given x and y~delta.
*
* @fields:
* paint ::
* An @FT_OpaquePaint object referencing the paint that is to be
* rotated.
*
* dx ::
* Translation in x~direction (in font units).
*
* dy ::
* Translation in y~direction (in font units).
*/
typedef struct FT_PaintTranslate_
{
FT_OpaquePaint paint;
FT_Fixed dx;
FT_Fixed dy;
} FT_PaintTranslate;
/**************************************************************************
*
* @struct:
* FT_PaintRotate
*
* @description:
* A structure representing a 'COLR' v1 `PaintRotate` paint table. Used
* for rotating downstream paints with a given center and angle.
*
* @fields:
* paint ::
* An @FT_OpaquePaint object referencing the paint that is to be
* rotated.
*
* angle ::
* The rotation angle that is to be applied.
*
* center_x ::
* The x~coordinate of the pivot point of the rotation (in font
* units).
*
* center_y ::
* The y~coordinate of the pivot point of the rotation (in font
* units).
*/
typedef struct FT_PaintRotate_
{
FT_OpaquePaint paint;
FT_Fixed angle;
FT_Fixed center_x;
FT_Fixed center_y;
} FT_PaintRotate;
/**************************************************************************
*
* @struct:
* FT_PaintSkew
*
* @description:
* A structure representing a 'COLR' v1 `PaintSkew` paint table. Used
* for skewing or shearing downstream paints by a given center and
* angle.
*
* @fields:
* paint ::
* An @FT_OpaquePaint object referencing the paint that is to be
* skewed.
*
* x_skew_angle ::
* The skewing angle in x~direction.
*
* y_skew_angle ::
* The skewing angle in y~direction.
*
* center_x ::
* The x~coordinate of the pivot point of the skew (in font units).
*
* center_y ::
* The y~coordinate of the pivot point of the skew (in font units).
*/
typedef struct FT_PaintSkew_
{
FT_OpaquePaint paint;
FT_Fixed x_skew_angle;
FT_Fixed y_skew_angle;
FT_Fixed center_x;
FT_Fixed center_y;
} FT_PaintSkew;
/**************************************************************************
*
* @struct:
* FT_PaintComposite
*
* @description:
* A structure representing a 'COLR'v1 `PaintComposite` paint table.
* Used for compositing two paints in a 'COLR' v1 directed acycling
* graph.
*
* @fields:
* source_paint ::
* An @FT_OpaquePaint object referencing the source that is to be
* composited.
*
* composite_mode ::
* An @FT_Composite_Mode enum value determining the composition
* operation.
*
* backdrop_paint ::
* An @FT_OpaquePaint object referencing the backdrop paint that
* `source_paint` is composited onto.
*/
typedef struct FT_PaintComposite_
{
FT_OpaquePaint source_paint;
FT_Composite_Mode composite_mode;
FT_OpaquePaint backdrop_paint;
} FT_PaintComposite;
/**************************************************************************
*
* @union:
* FT_COLR_Paint
*
* @description:
* A union object representing format and details of a paint table of a
* 'COLR' v1 font, see
* 'https://github.com/googlefonts/colr-gradients-spec'. Use
* @FT_Get_Paint to retrieve a @FT_COLR_Paint for an @FT_OpaquePaint
* object.
*
* @fields:
* format ::
* The gradient format for this Paint structure.
*
* u ::
* Union of all paint table types:
*
* * @FT_PaintColrLayers
* * @FT_PaintGlyph
* * @FT_PaintSolid
* * @FT_PaintLinearGradient
* * @FT_PaintRadialGradient
* * @FT_PaintTransformed
* * @FT_PaintTranslate
* * @FT_PaintRotate
* * @FT_PaintSkew
* * @FT_PaintComposite
* * @FT_PaintColrGlyph
*/
typedef struct FT_COLR_Paint_
{
FT_PaintFormat format;
union
{
FT_PaintColrLayers colr_layers;
FT_PaintGlyph glyph;
FT_PaintSolid solid;
FT_PaintLinearGradient linear_gradient;
FT_PaintRadialGradient radial_gradient;
FT_PaintTransformed transformed;
FT_PaintTranslate translate;
FT_PaintRotate rotate;
FT_PaintSkew skew;
FT_PaintComposite composite;
FT_PaintColrGlyph colr_glyph;
} u;
} FT_COLR_Paint;
/**************************************************************************
*
* @section: