hb_paint_funcs_create ()

hb_paint_funcs_t *
hb_paint_funcs_create (void);

Creates a new hb_paint_funcs_t structure of paint functions.

The initial reference count of 1 should be released with hb_paint_funcs_destroy() when you are done using the hb_paint_funcs_t. This function never returns NULL. If memory cannot be allocated, a special singleton hb_paint_funcs_t object will be returned.

Returns value: (transfer full): the paint-functions structure

Since: 7.0.0

hb_paint_funcs_get_empty ()

hb_paint_funcs_t *
hb_paint_funcs_get_empty (void);

Fetches the singleton empty paint-functions structure.

Since: 7.0.0

hb_paint_funcs_reference ()

hb_paint_funcs_t *
hb_paint_funcs_reference (hb_paint_funcs_t *funcs);

Increases the reference count on a paint-functions structure.

This prevents funcs from being destroyed until a matching call to hb_paint_funcs_destroy() is made.

[skip]

Since: 7.0.0

hb_paint_funcs_destroy ()

void
hb_paint_funcs_destroy (hb_paint_funcs_t *funcs);

Decreases the reference count on a paint-functions structure.

When the reference count reaches zero, the structure is destroyed, freeing all memory.

[skip]

Since: 7.0.0

hb_paint_funcs_set_user_data ()

hb_bool_t
hb_paint_funcs_set_user_data (hb_paint_funcs_t *funcs,
                              hb_user_data_key_t *key,
                              void *data,
                              hb_destroy_func_t destroy,
                              hb_bool_t replace);

Attaches a user-data key/data pair to the specified paint-functions structure.

[skip]

Since: 7.0.0

hb_paint_funcs_get_user_data ()

void *
hb_paint_funcs_get_user_data (const hb_paint_funcs_t *funcs,
                              hb_user_data_key_t *key);

Fetches the user-data associated with the specified key, attached to the specified paint-functions structure.

[skip]

Since: 7.0.0

hb_paint_funcs_make_immutable ()

void
hb_paint_funcs_make_immutable (hb_paint_funcs_t *funcs);

Makes a paint-functions structure immutable.

After this call, all attempts to set one of the callbacks on funcs will fail.

Since: 7.0.0

hb_paint_funcs_is_immutable ()

hb_bool_t
hb_paint_funcs_is_immutable (hb_paint_funcs_t *funcs);

Tests whether a paint-functions structure is immutable.

Since: 7.0.0

hb_paint_push_transform_func_t ()

void
(*hb_paint_push_transform_func_t) (hb_paint_funcs_t *funcs,
                                   void *paint_data,
                                   float xx,
                                   float yx,
                                   float xy,
                                   float yy,
                                   float dx,
                                   float dy,
                                   void *user_data);

A virtual method for the hb_paint_funcs_t to apply a transform to subsequent paint calls.

This transform is applied after the current transform, and remains in effect until a matching call to the hb_paint_funcs_pop_transform_func_t vfunc.

Since: 7.0.0

hb_paint_funcs_set_push_transform_func ()

void
hb_paint_funcs_set_push_transform_func
                               (hb_paint_funcs_t *funcs,
                                hb_paint_push_transform_func_t func,
                                void *user_data,
                                hb_destroy_func_t destroy);

Sets the push-transform callback on the paint functions struct.

Since: 7.0.0

hb_paint_pop_transform_func_t ()

void
(*hb_paint_pop_transform_func_t) (hb_paint_funcs_t *funcs,
                                  void *paint_data,
                                  void *user_data);

A virtual method for the hb_paint_funcs_t to undo the effect of a prior call to the hb_paint_funcs_push_transform_func_t vfunc.

Since: 7.0.0

hb_paint_funcs_set_pop_transform_func ()

void
hb_paint_funcs_set_pop_transform_func (hb_paint_funcs_t *funcs,
                                       hb_paint_pop_transform_func_t func,
                                       void *user_data,
                                       hb_destroy_func_t destroy);

Sets the pop-transform callback on the paint functions struct.

Since: 7.0.0

hb_paint_color_glyph_func_t ()

hb_bool_t
(*hb_paint_color_glyph_func_t) (hb_paint_funcs_t *funcs,
                                void *paint_data,
                                hb_codepoint_t glyph,
                                hb_font_t *font,
                                void *user_data);

A virtual method for the hb_paint_funcs_t to render a color glyph by glyph index.

Since: 8.2.0

hb_paint_funcs_set_color_glyph_func ()

void
hb_paint_funcs_set_color_glyph_func (hb_paint_funcs_t *funcs,
                                     hb_paint_color_glyph_func_t func,
                                     void *user_data,
                                     hb_destroy_func_t destroy);

Sets the color-glyph callback on the paint functions struct.

Since: 8.2.0

hb_paint_push_clip_glyph_func_t ()

void
(*hb_paint_push_clip_glyph_func_t) (hb_paint_funcs_t *funcs,
                                    void *paint_data,
                                    hb_codepoint_t glyph,
                                    hb_font_t *font,
                                    void *user_data);

A virtual method for the hb_paint_funcs_t to clip subsequent paint calls to the outline of a glyph.

The coordinates of the glyph outline are interpreted according to the current transform.

This clip is applied in addition to the current clip, and remains in effect until a matching call to the hb_paint_funcs_pop_clip_func_t vfunc.

Since: 7.0.0

hb_paint_funcs_set_push_clip_glyph_func ()

void
hb_paint_funcs_set_push_clip_glyph_func
                               (hb_paint_funcs_t *funcs,
                                hb_paint_push_clip_glyph_func_t func,
                                void *user_data,
                                hb_destroy_func_t destroy);

Sets the push-clip-glyph callback on the paint functions struct.

Since: 7.0.0

hb_paint_push_clip_rectangle_func_t ()

void
(*hb_paint_push_clip_rectangle_func_t)
                               (hb_paint_funcs_t *funcs,
                                void *paint_data,
                                float xmin,
                                float ymin,
                                float xmax,
                                float ymax,
                                void *user_data);

A virtual method for the hb_paint_funcs_t to clip subsequent paint calls to a rectangle.

The coordinates of the rectangle are interpreted according to the current transform.

This clip is applied in addition to the current clip, and remains in effect until a matching call to the hb_paint_funcs_pop_clip_func_t vfunc.

Since: 7.0.0

hb_paint_funcs_set_push_clip_rectangle_func ()

void
hb_paint_funcs_set_push_clip_rectangle_func
                               (hb_paint_funcs_t *funcs,
                                hb_paint_push_clip_rectangle_func_t func,
                                void *user_data,
                                hb_destroy_func_t destroy);

Sets the push-clip-rect callback on the paint functions struct.

Since: 7.0.0

hb_paint_pop_clip_func_t ()

void
(*hb_paint_pop_clip_func_t) (hb_paint_funcs_t *funcs,
                             void *paint_data,
                             void *user_data);

A virtual method for the hb_paint_funcs_t to undo the effect of a prior call to the hb_paint_funcs_push_clip_glyph_func_t or hb_paint_funcs_push_clip_rectangle_func_t vfuncs.

Since: 7.0.0

hb_paint_funcs_set_pop_clip_func ()

void
hb_paint_funcs_set_pop_clip_func (hb_paint_funcs_t *funcs,
                                  hb_paint_pop_clip_func_t func,
                                  void *user_data,
                                  hb_destroy_func_t destroy);

Sets the pop-clip callback on the paint functions struct.

Since: 7.0.0

hb_paint_color_func_t ()

void
(*hb_paint_color_func_t) (hb_paint_funcs_t *funcs,
                          void *paint_data,
                          hb_bool_t is_foreground,
                          hb_color_t color,
                          void *user_data);

A virtual method for the hb_paint_funcs_t to paint a color everywhere within the current clip.

Since: 7.0.0

hb_paint_funcs_set_color_func ()

void
hb_paint_funcs_set_color_func (hb_paint_funcs_t *funcs,
                               hb_paint_color_func_t func,
                               void *user_data,
                               hb_destroy_func_t destroy);

Sets the paint-color callback on the paint functions struct.

Since: 7.0.0

hb_paint_image_func_t ()

hb_bool_t
(*hb_paint_image_func_t) (hb_paint_funcs_t *funcs,
                          void *paint_data,
                          hb_blob_t *image,
                          unsigned int width,
                          unsigned int height,
                          hb_tag_t format,
                          float slant,
                          hb_glyph_extents_t *extents,
                          void *user_data);

A virtual method for the hb_paint_funcs_t to paint a glyph image.

This method is called for glyphs with image blobs in the CBDT, sbix or SVG tables. The format identifies the kind of data that is contained in image . Possible values include HB_PAINT_IMAGE_FORMAT_PNG, HB_PAINT_IMAGE_FORMAT_SVG and HB_PAINT_IMAGE_FORMAT_BGRA.

The image dimensions and glyph extents are provided if available, and should be used to size and position the image.

Since: 7.0.0

hb_paint_funcs_set_image_func ()

void
hb_paint_funcs_set_image_func (hb_paint_funcs_t *funcs,
                               hb_paint_image_func_t func,
                               void *user_data,
                               hb_destroy_func_t destroy);

Sets the paint-image callback on the paint functions struct.

Since: 7.0.0

hb_color_line_get_color_stops_func_t ()

unsigned int
(*hb_color_line_get_color_stops_func_t)
                               (hb_color_line_t *color_line,
                                void *color_line_data,
                                unsigned int start,
                                unsigned int *count,
                                hb_color_stop_t *color_stops,
                                void *user_data);

A virtual method for the hb_color_line_t to fetch color stops.

Since: 7.0.0

hb_color_line_get_color_stops ()

unsigned int
hb_color_line_get_color_stops (hb_color_line_t *color_line,
                               unsigned int start,
                               unsigned int *count,
                               hb_color_stop_t *color_stops);

Fetches a list of color stops from the given color line object.

Note that due to variations being applied, the returned color stops may be out of order. It is the callers responsibility to ensure that color stops are sorted by their offset before they are used.

Since: 7.0.0

hb_color_line_get_extend_func_t ()

hb_paint_extend_t
(*hb_color_line_get_extend_func_t) (hb_color_line_t *color_line,
                                    void *color_line_data,
                                    void *user_data);

A virtual method for the hb_color_line_t to fetches the extend mode.

Since: 7.0.0

hb_color_line_get_extend ()

hb_paint_extend_t
hb_color_line_get_extend (hb_color_line_t *color_line);

Fetches the extend mode of the color line object.

Since: 7.0.0

hb_paint_linear_gradient_func_t ()

void
(*hb_paint_linear_gradient_func_t) (hb_paint_funcs_t *funcs,
                                    void *paint_data,
                                    hb_color_line_t *color_line,
                                    float x0,
                                    float y0,
                                    float x1,
                                    float y1,
                                    float x2,
                                    float y2,
                                    void *user_data);

A virtual method for the hb_paint_funcs_t to paint a linear gradient everywhere within the current clip.

The color_line object contains information about the colors of the gradients. It is only valid for the duration of the callback, you cannot keep it around.

The coordinates of the points are interpreted according to the current transform.

See the OpenType spec COLR section for details on how the points define the direction of the gradient, and how to interpret the color_line .

Since: 7.0.0

hb_paint_funcs_set_linear_gradient_func ()

void
hb_paint_funcs_set_linear_gradient_func
                               (hb_paint_funcs_t *funcs,
                                hb_paint_linear_gradient_func_t func,
                                void *user_data,
                                hb_destroy_func_t destroy);

Sets the linear-gradient callback on the paint functions struct.

Since: 7.0.0

hb_paint_radial_gradient_func_t ()

void
(*hb_paint_radial_gradient_func_t) (hb_paint_funcs_t *funcs,
                                    void *paint_data,
                                    hb_color_line_t *color_line,
                                    float x0,
                                    float y0,
                                    float r0,
                                    float x1,
                                    float y1,
                                    float r1,
                                    void *user_data);

A virtual method for the hb_paint_funcs_t to paint a radial gradient everywhere within the current clip.

The color_line object contains information about the colors of the gradients. It is only valid for the duration of the callback, you cannot keep it around.

The coordinates of the points are interpreted according to the current transform.

See the OpenType spec COLR section for details on how the points define the direction of the gradient, and how to interpret the color_line .

Since: 7.0.0

hb_paint_funcs_set_radial_gradient_func ()

void
hb_paint_funcs_set_radial_gradient_func
                               (hb_paint_funcs_t *funcs,
                                hb_paint_radial_gradient_func_t func,
                                void *user_data,
                                hb_destroy_func_t destroy);

Sets the radial-gradient callback on the paint functions struct.

Since: 7.0.0

hb_paint_sweep_gradient_func_t ()

void
(*hb_paint_sweep_gradient_func_t) (hb_paint_funcs_t *funcs,
                                   void *paint_data,
                                   hb_color_line_t *color_line,
                                   float x0,
                                   float y0,
                                   float start_angle,
                                   float end_angle,
                                   void *user_data);

A virtual method for the hb_paint_funcs_t to paint a sweep gradient everywhere within the current clip.

The color_line object contains information about the colors of the gradients. It is only valid for the duration of the callback, you cannot keep it around.

The coordinates of the points are interpreted according to the current transform.

See the OpenType spec COLR section for details on how the points define the direction of the gradient, and how to interpret the color_line .

Since: 7.0.0

hb_paint_funcs_set_sweep_gradient_func ()

void
hb_paint_funcs_set_sweep_gradient_func
                               (hb_paint_funcs_t *funcs,
                                hb_paint_sweep_gradient_func_t func,
                                void *user_data,
                                hb_destroy_func_t destroy);

Sets the sweep-gradient callback on the paint functions struct.

Since: 7.0.0

hb_paint_push_group_func_t ()

void
(*hb_paint_push_group_func_t) (hb_paint_funcs_t *funcs,
                               void *paint_data,
                               void *user_data);

A virtual method for the hb_paint_funcs_t to use an intermediate surface for subsequent paint calls.

The drawing will be redirected to an intermediate surface until a matching call to the hb_paint_funcs_pop_group_func_t vfunc.

Since: 7.0.0

hb_paint_funcs_set_push_group_func ()

void
hb_paint_funcs_set_push_group_func (hb_paint_funcs_t *funcs,
                                    hb_paint_push_group_func_t func,
                                    void *user_data,
                                    hb_destroy_func_t destroy);

Sets the push-group callback on the paint functions struct.

Since: 7.0.0

hb_paint_pop_group_func_t ()

void
(*hb_paint_pop_group_func_t) (hb_paint_funcs_t *funcs,
                              void *paint_data,
                              hb_paint_composite_mode_t mode,
                              void *user_data);

A virtual method for the hb_paint_funcs_t to undo the effect of a prior call to the hb_paint_funcs_push_group_func_t vfunc.

This call stops the redirection to the intermediate surface, and then composites it on the previous surface, using the compositing mode passed to this call.

Since: 7.0.0

hb_paint_funcs_set_pop_group_func ()

void
hb_paint_funcs_set_pop_group_func (hb_paint_funcs_t *funcs,
                                   hb_paint_pop_group_func_t func,
                                   void *user_data,
                                   hb_destroy_func_t destroy);

Sets the pop-group callback on the paint functions struct.

Since: 7.0.0

hb_paint_custom_palette_color_func_t ()

hb_bool_t
(*hb_paint_custom_palette_color_func_t)
                               (hb_paint_funcs_t *funcs,
                                void *paint_data,
                                unsigned int color_index,
                                hb_color_t *color,
                                void *user_data);

A virtual method for the hb_paint_funcs_t to fetch a color from the custom color palette.

Custom palette colors override the colors from the fonts selected color palette. It is not necessary to override all palette entries; for entries that should be taken from the font palette, return false.

This function might get called multiple times, but the custom palette is expected to remain unchanged for duration of a hb_font_paint_glyph() call.

Since: 7.0.0

hb_paint_funcs_set_custom_palette_color_func ()

void
hb_paint_funcs_set_custom_palette_color_func
                               (hb_paint_funcs_t *funcs,
                                hb_paint_custom_palette_color_func_t func,
                                void *user_data,
                                hb_destroy_func_t destroy);

Sets the custom-palette-color callback on the paint functions struct.

Since: 7.0.0

hb_paint_push_transform ()

void
hb_paint_push_transform (hb_paint_funcs_t *funcs,
                         void *paint_data,
                         float xx,
                         float yx,
                         float xy,
                         float yy,
                         float dx,
                         float dy);

Perform a "push-transform" paint operation.

Since: 7.0.0

hb_paint_pop_transform ()

void
hb_paint_pop_transform (hb_paint_funcs_t *funcs,
                        void *paint_data);

Perform a "pop-transform" paint operation.

Since: 7.0.0

hb_paint_color_glyph ()

hb_bool_t
hb_paint_color_glyph (hb_paint_funcs_t *funcs,
                      void *paint_data,
                      hb_codepoint_t glyph,
                      hb_font_t *font);

Perform a "color-glyph" paint operation.

Since: 8.2.0

hb_paint_push_clip_glyph ()

void
hb_paint_push_clip_glyph (hb_paint_funcs_t *funcs,
                          void *paint_data,
                          hb_codepoint_t glyph,
                          hb_font_t *font);

Perform a "push-clip-glyph" paint operation.

Since: 7.0.0

hb_paint_push_clip_rectangle ()

void
hb_paint_push_clip_rectangle (hb_paint_funcs_t *funcs,
                              void *paint_data,
                              float xmin,
                              float ymin,
                              float xmax,
                              float ymax);

Perform a "push-clip-rect" paint operation.

Since: 7.0.0

hb_paint_pop_clip ()

void
hb_paint_pop_clip (hb_paint_funcs_t *funcs,
                   void *paint_data);

Perform a "pop-clip" paint operation.

Since: 7.0.0

hb_paint_color ()

void
hb_paint_color (hb_paint_funcs_t *funcs,
                void *paint_data,
                hb_bool_t is_foreground,
                hb_color_t color);

Perform a "color" paint operation.

Since: 7.0.0

hb_paint_image ()

void
hb_paint_image (hb_paint_funcs_t *funcs,
                void *paint_data,
                hb_blob_t *image,
                unsigned int width,
                unsigned int height,
                hb_tag_t format,
                float slant,
                hb_glyph_extents_t *extents);

Perform a "image" paint operation.

Since: 7.0.0

hb_paint_linear_gradient ()

void
hb_paint_linear_gradient (hb_paint_funcs_t *funcs,
                          void *paint_data,
                          hb_color_line_t *color_line,
                          float x0,
                          float y0,
                          float x1,
                          float y1,
                          float x2,
                          float y2);

Perform a "linear-gradient" paint operation.

Since: 7.0.0

hb_paint_radial_gradient ()

void
hb_paint_radial_gradient (hb_paint_funcs_t *funcs,
                          void *paint_data,
                          hb_color_line_t *color_line,
                          float x0,
                          float y0,
                          float r0,
                          float x1,
                          float y1,
                          float r1);

Perform a "radial-gradient" paint operation.

Since: 7.0.0

hb_paint_sweep_gradient ()

void
hb_paint_sweep_gradient (hb_paint_funcs_t *funcs,
                         void *paint_data,
                         hb_color_line_t *color_line,
                         float x0,
                         float y0,
                         float start_angle,
                         float end_angle);

Perform a "sweep-gradient" paint operation.

Since: 7.0.0

hb_paint_push_group ()

void
hb_paint_push_group (hb_paint_funcs_t *funcs,
                     void *paint_data);

Perform a "push-group" paint operation.

Since: 7.0.0

hb_paint_pop_group ()

void
hb_paint_pop_group (hb_paint_funcs_t *funcs,
                    void *paint_data,
                    hb_paint_composite_mode_t mode);

Perform a "pop-group" paint operation.

Since: 7.0.0

hb_paint_custom_palette_color ()

hb_bool_t
hb_paint_custom_palette_color (hb_paint_funcs_t *funcs,
                               void *paint_data,
                               unsigned int color_index,
                               hb_color_t *color);

Gets the custom palette color for color_index .

Since: 7.0.0

hb_paint_funcs_t

typedef struct hb_paint_funcs_t hb_paint_funcs_t;

Glyph paint callbacks.

The callbacks assume that the caller maintains a stack of current transforms, clips and intermediate surfaces, as evidenced by the pairs of push/pop callbacks. The push/pop calls will be properly nested, so it is fine to store the different kinds of object on a single stack.

Not all callbacks are required for all kinds of glyphs. For rendering COLRv0 or non-color outline glyphs, the gradient callbacks are not needed, and the composite callback only needs to handle simple alpha compositing (HB_PAINT_COMPOSITE_MODE_SRC_OVER).

The paint-image callback is only needed for glyphs with image blobs in the CBDT, sbix or SVG tables.

The custom-palette-color callback is only necessary if you want to override colors from the font palette with custom colors.

Since: 7.0.0

HB_PAINT_IMAGE_FORMAT_PNG

#define HB_PAINT_IMAGE_FORMAT_PNG HB_TAG('p','n','g',' ')

Tag identifying PNG images in hb_paint_image_func_t callbacks.

Since: 7.0.0

HB_PAINT_IMAGE_FORMAT_SVG

#define HB_PAINT_IMAGE_FORMAT_SVG HB_TAG('s','v','g',' ')

Tag identifying SVG images in hb_paint_image_func_t callbacks.

Since: 7.0.0

HB_PAINT_IMAGE_FORMAT_BGRA

#define HB_PAINT_IMAGE_FORMAT_BGRA HB_TAG('B','G','R','A')

Tag identifying raw pixel-data images in hb_paint_image_func_t callbacks. The data is in BGRA pre-multiplied sRGBA color-space format.

Since: 7.0.0

hb_color_line_t

typedef struct hb_color_line_t hb_color_line_t;

A struct containing color information for a gradient.

Since: 7.0.0

hb_color_stop_t

typedef struct {
  float offset;
  hb_bool_t is_foreground;
  hb_color_t color;
} hb_color_stop_t;

Information about a color stop on a color line.

Color lines typically have offsets ranging between 0 and 1, but that is not required.

Note: despite color being unpremultiplied here, interpolation in gradients shall happen in premultiplied space. See the OpenType spec COLR section for details.

Since: 7.0.0

enum hb_paint_extend_t

The values of this enumeration determine how color values outside the minimum and maximum defined offset on a hb_color_line_t are determined.

See the OpenType spec COLR section for details.

Since: 7.0.0

enum hb_paint_composite_mode_t

The values of this enumeration describe the compositing modes that can be used when combining temporary redirected drawing with the backdrop.

See the OpenType spec COLR section for details.

Since: 7.0.0