hb_draw_funcs_create ()

hb_draw_funcs_t *
hb_draw_funcs_create (void);

Creates a new draw callbacks object.

Since: 4.0.0

hb_draw_funcs_get_empty ()

hb_draw_funcs_t *
hb_draw_funcs_get_empty (void);

Fetches the singleton empty draw-functions structure.

Since: 7.0.0

hb_draw_funcs_reference ()

hb_draw_funcs_t *
hb_draw_funcs_reference (hb_draw_funcs_t *dfuncs);

Increases the reference count on dfuncs by one.

This prevents dfuncs from being destroyed until a matching call to hb_draw_funcs_destroy() is made.

[skip]

Since: 4.0.0

hb_draw_funcs_destroy ()

void
hb_draw_funcs_destroy (hb_draw_funcs_t *dfuncs);

Deallocate the dfuncs . Decreases the reference count on dfuncs by one. If the result is zero, then dfuncs and all associated resources are freed. See hb_draw_funcs_reference().

[skip]

Since: 4.0.0

hb_draw_funcs_set_user_data ()

hb_bool_t
hb_draw_funcs_set_user_data (hb_draw_funcs_t *dfuncs,
                             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 draw-functions structure.

[skip]

Since: 7.0.0

hb_draw_funcs_get_user_data ()

void *
hb_draw_funcs_get_user_data (const hb_draw_funcs_t *dfuncs,
                             hb_user_data_key_t *key);

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

[skip]

Since: 7.0.0

hb_draw_funcs_make_immutable ()

void
hb_draw_funcs_make_immutable (hb_draw_funcs_t *dfuncs);

Makes dfuncs object immutable.

Since: 4.0.0

hb_draw_funcs_is_immutable ()

hb_bool_t
hb_draw_funcs_is_immutable (hb_draw_funcs_t *dfuncs);

Checks whether dfuncs is immutable.

Since: 4.0.0

hb_draw_move_to_func_t ()

void
(*hb_draw_move_to_func_t) (hb_draw_funcs_t *dfuncs,
                           void *draw_data,
                           hb_draw_state_t *st,
                           float to_x,
                           float to_y,
                           void *user_data);

A virtual method for the hb_draw_funcs_t to perform a "move-to" draw operation.

Since: 4.0.0

hb_draw_funcs_set_move_to_func ()

void
hb_draw_funcs_set_move_to_func (hb_draw_funcs_t *dfuncs,
                                hb_draw_move_to_func_t func,
                                void *user_data,
                                hb_destroy_func_t destroy);

Sets move-to callback to the draw functions object.

Since: 4.0.0

hb_draw_line_to_func_t ()

void
(*hb_draw_line_to_func_t) (hb_draw_funcs_t *dfuncs,
                           void *draw_data,
                           hb_draw_state_t *st,
                           float to_x,
                           float to_y,
                           void *user_data);

A virtual method for the hb_draw_funcs_t to perform a "line-to" draw operation.

Since: 4.0.0

hb_draw_funcs_set_line_to_func ()

void
hb_draw_funcs_set_line_to_func (hb_draw_funcs_t *dfuncs,
                                hb_draw_line_to_func_t func,
                                void *user_data,
                                hb_destroy_func_t destroy);

Sets line-to callback to the draw functions object.

Since: 4.0.0

hb_draw_quadratic_to_func_t ()

void
(*hb_draw_quadratic_to_func_t) (hb_draw_funcs_t *dfuncs,
                                void *draw_data,
                                hb_draw_state_t *st,
                                float control_x,
                                float control_y,
                                float to_x,
                                float to_y,
                                void *user_data);

A virtual method for the hb_draw_funcs_t to perform a "quadratic-to" draw operation.

Since: 4.0.0

hb_draw_funcs_set_quadratic_to_func ()

void
hb_draw_funcs_set_quadratic_to_func (hb_draw_funcs_t *dfuncs,
                                     hb_draw_quadratic_to_func_t func,
                                     void *user_data,
                                     hb_destroy_func_t destroy);

Sets quadratic-to callback to the draw functions object.

Since: 4.0.0

hb_draw_cubic_to_func_t ()

void
(*hb_draw_cubic_to_func_t) (hb_draw_funcs_t *dfuncs,
                            void *draw_data,
                            hb_draw_state_t *st,
                            float control1_x,
                            float control1_y,
                            float control2_x,
                            float control2_y,
                            float to_x,
                            float to_y,
                            void *user_data);

A virtual method for the hb_draw_funcs_t to perform a "cubic-to" draw operation.

Since: 4.0.0

hb_draw_funcs_set_cubic_to_func ()

void
hb_draw_funcs_set_cubic_to_func (hb_draw_funcs_t *dfuncs,
                                 hb_draw_cubic_to_func_t func,
                                 void *user_data,
                                 hb_destroy_func_t destroy);

Sets cubic-to callback to the draw functions object.

Since: 4.0.0

hb_draw_close_path_func_t ()

void
(*hb_draw_close_path_func_t) (hb_draw_funcs_t *dfuncs,
                              void *draw_data,
                              hb_draw_state_t *st,
                              void *user_data);

A virtual method for the hb_draw_funcs_t to perform a "close-path" draw operation.

Since: 4.0.0

hb_draw_funcs_set_close_path_func ()

void
hb_draw_funcs_set_close_path_func (hb_draw_funcs_t *dfuncs,
                                   hb_draw_close_path_func_t func,
                                   void *user_data,
                                   hb_destroy_func_t destroy);

Sets close-path callback to the draw functions object.

Since: 4.0.0

hb_draw_move_to ()

void
hb_draw_move_to (hb_draw_funcs_t *dfuncs,
                 void *draw_data,
                 hb_draw_state_t *st,
                 float to_x,
                 float to_y);

Perform a "move-to" draw operation.

Since: 4.0.0

hb_draw_line_to ()

void
hb_draw_line_to (hb_draw_funcs_t *dfuncs,
                 void *draw_data,
                 hb_draw_state_t *st,
                 float to_x,
                 float to_y);

Perform a "line-to" draw operation.

Since: 4.0.0

hb_draw_quadratic_to ()

void
hb_draw_quadratic_to (hb_draw_funcs_t *dfuncs,
                      void *draw_data,
                      hb_draw_state_t *st,
                      float control_x,
                      float control_y,
                      float to_x,
                      float to_y);

Perform a "quadratic-to" draw operation.

Since: 4.0.0

hb_draw_cubic_to ()

void
hb_draw_cubic_to (hb_draw_funcs_t *dfuncs,
                  void *draw_data,
                  hb_draw_state_t *st,
                  float control1_x,
                  float control1_y,
                  float control2_x,
                  float control2_y,
                  float to_x,
                  float to_y);

Perform a "cubic-to" draw operation.

Since: 4.0.0

hb_draw_close_path ()

void
hb_draw_close_path (hb_draw_funcs_t *dfuncs,
                    void *draw_data,
                    hb_draw_state_t *st);

Perform a "close-path" draw operation.

Since: 4.0.0

hb_draw_line ()

void
hb_draw_line (hb_draw_funcs_t *dfuncs,
              void *draw_data,
              hb_draw_state_t *st,
              float x0,
              float y0,
              float w0,
              float x1,
              float y1,
              float w1,
              hb_draw_line_cap_t cap);

Emits a tapered line segment as a filled trapezoid. w0 and w1 are the full stroke widths at the start and end points respectively; they may differ for a tapered stroke or match for a uniform one. Pass NaN for w1 to use w0 (uniform stroke) without repeating the value.

With HB_DRAW_LINE_CAP_SQUARE each endpoint is extended along the line direction by half its local stroke width, so four hb_draw_line() calls form a closed rectangle without gaps at the corners.

Since: 14.2.0

hb_draw_rectangle ()

void
hb_draw_rectangle (hb_draw_funcs_t *dfuncs,
                   void *draw_data,
                   hb_draw_state_t *st,
                   float x,
                   float y,
                   float w,
                   float h,
                   float stroke_width);

Emits an axis-aligned rectangle. If stroke_width is a finite positive value, the rectangle is rendered as an outlined ring of that thickness centered on the edges; if stroke_width is NaN, the rectangle is rendered filled.

Note: stroked rectangles produce a bounding box covering the full outer rectangle, so if the pen is a GPU fragment-shader backend, the shader runs for every interior pixel even though only the outline contributes coverage. For very thin outlines where the interior is much larger than the stroke, emitting four hb_draw_line() segments (one per edge) is considerably cheaper per frame.

Since: 14.2.0

hb_draw_circle ()

void
hb_draw_circle (hb_draw_funcs_t *dfuncs,
                void *draw_data,
                hb_draw_state_t *st,
                float cx,
                float cy,
                float r,
                float stroke_width);

Emits a circle approximated by four cubic Bezier curves. If stroke_width is a finite positive value, the circle is rendered as an outlined ring of that thickness centered on the nominal radius; if stroke_width is NaN, the circle is rendered as a filled disc.

Since: 14.2.0

enum hb_draw_line_cap_t

End-cap shape for hb_draw_line().

Since: 14.2.0

HB_DRAW_STATE_DEFAULT

#define HB_DRAW_STATE_DEFAULT {0, 0.f, 0.f, 0.f, 0.f, {0}, {0}, {0}, {0}, {0}, {0}, {0}}

The default hb_draw_state_t at the start of glyph drawing.

hb_draw_funcs_t

typedef struct hb_draw_funcs_t hb_draw_funcs_t;

Glyph draw callbacks.

hb_draw_move_to_func_t, hb_draw_line_to_func_t and hb_draw_cubic_to_func_t calls are necessary to be defined but we translate hb_draw_quadratic_to_func_t calls to hb_draw_cubic_to_func_t if the callback isn't defined.

Since: 4.0.0

hb_draw_state_t

typedef struct {
  hb_bool_t path_open;

  float path_start_x;
  float path_start_y;

  float current_x;
  float current_y;
} hb_draw_state_t;

Current drawing state.

Since: 4.0.0