/*
* Copyright © 2022 Matthias Clasen
*
* This is part of HarfBuzz, a text shaping library.
*
* Permission is hereby granted, without written agreement and without
* license or royalty fees, to use, copy, modify, and distribute this
* software and its documentation for any purpose, provided that the
* above copyright notice and the following two paragraphs appear in
* all copies of this software.
*
* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*
* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
*/
#include "hb.hh"
#ifndef HB_NO_PAINT
#include "hb-paint.hh"
/**
* SECTION: hb-paint
* @title: hb-paint
* @short_description: Glyph painting
* @include: hb.h
*
* Functions for painting glyphs.
*
* The main purpose of these functions is to paint (extract) color glyph layers
* from the COLRv1 table, but the API works for drawing ordinary outlines and
* images as well.
*
* The #hb_paint_funcs_t struct can be used with hb_font_paint_glyph().
**/
static void
hb_paint_push_transform_nil (hb_paint_funcs_t *funcs, void *paint_data,
float xx, float yx,
float xy, float yy,
float dx, float dy,
void *user_data) {}
static void
hb_paint_pop_transform_nil (hb_paint_funcs_t *funcs, void *paint_data,
void *user_data) {}
static hb_bool_t
hb_paint_color_glyph_nil (hb_paint_funcs_t *funcs, void *paint_data,
hb_codepoint_t glyph,
hb_font_t *font,
void *user_data) { return false; }
static void
hb_paint_push_clip_glyph_nil (hb_paint_funcs_t *funcs, void *paint_data,
hb_codepoint_t glyph,
hb_font_t *font,
void *user_data) {}
static void
hb_paint_push_clip_rectangle_nil (hb_paint_funcs_t *funcs, void *paint_data,
float xmin, float ymin, float xmax, float ymax,
void *user_data) {}
static hb_draw_funcs_t *
hb_paint_push_clip_path_start_nil (hb_paint_funcs_t *funcs, void *paint_data,
void **draw_data,
void *user_data) { if (draw_data) *draw_data = nullptr; return nullptr; }
static void
hb_paint_push_clip_path_end_nil (hb_paint_funcs_t *funcs, void *paint_data,
void *user_data) {}
static void
hb_paint_pop_clip_nil (hb_paint_funcs_t *funcs, void *paint_data,
void *user_data) {}
static void
hb_paint_color_nil (hb_paint_funcs_t *funcs, void *paint_data,
hb_bool_t is_foreground,
hb_color_t color,
void *user_data) {}
static hb_bool_t
hb_paint_image_nil (hb_paint_funcs_t *funcs, void *paint_data,
hb_blob_t *image,
unsigned int width,
unsigned int height,
hb_tag_t format,
float slant_xy_deprecated,
hb_glyph_extents_t *extents,
void *user_data) { return false; }
static void
hb_paint_linear_gradient_nil (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) {}
static void
hb_paint_radial_gradient_nil (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) {}
static void
hb_paint_sweep_gradient_nil (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) {}
static void
hb_paint_push_group_nil (hb_paint_funcs_t *funcs, void *paint_data,
void *user_data) {}
static void
hb_paint_push_group_for_nil (hb_paint_funcs_t *funcs, void *paint_data,
hb_paint_composite_mode_t mode,
void *user_data)
{
hb_paint_push_group (funcs, paint_data);
}
static void
hb_paint_pop_group_nil (hb_paint_funcs_t *funcs, void *paint_data,
hb_paint_composite_mode_t mode,
void *user_data) {}
static hb_bool_t
hb_paint_custom_palette_color_nil (hb_paint_funcs_t *funcs, void *paint_data,
unsigned int color_index,
hb_color_t *color,
void *user_data) { return false; }
static bool
_hb_paint_funcs_set_preamble (hb_paint_funcs_t *funcs,
bool func_is_null,
void **user_data,
hb_destroy_func_t *destroy)
{
if (hb_object_is_immutable (funcs))
{
if (*destroy)
(*destroy) (*user_data);
return false;
}
if (func_is_null)
{
if (*destroy)
(*destroy) (*user_data);
*destroy = nullptr;
*user_data = nullptr;
}
return true;
}
static bool
_hb_paint_funcs_set_middle (hb_paint_funcs_t *funcs,
void *user_data,
hb_destroy_func_t destroy)
{
auto destroy_guard = hb_make_scope_guard ([&]() {
if (destroy) destroy (user_data);
});
if (user_data && !funcs->user_data)
{
funcs->user_data = (decltype (funcs->user_data)) hb_calloc (1, sizeof (*funcs->user_data));
if (unlikely (!funcs->user_data))
return false;
}
if (destroy && !funcs->destroy)
{
funcs->destroy = (decltype (funcs->destroy)) hb_calloc (1, sizeof (*funcs->destroy));
if (unlikely (!funcs->destroy))
return false;
}
destroy_guard.release ();
return true;
}
#define HB_PAINT_FUNC_IMPLEMENT(name) \
\
void \
hb_paint_funcs_set_##name##_func (hb_paint_funcs_t *funcs, \
hb_paint_##name##_func_t func, \
void *user_data, \
hb_destroy_func_t destroy) \
{ \
if (!_hb_paint_funcs_set_preamble (funcs, !func, &user_data, &destroy)) \
return; \
\
if (funcs->destroy && funcs->destroy->name) \
funcs->destroy->name (!funcs->user_data ? nullptr : funcs->user_data->name);\
\
if (!_hb_paint_funcs_set_middle (funcs, user_data, destroy)) \
return; \
\
if (func) \
funcs->func.name = func; \
else \
funcs->func.name = hb_paint_##name##_nil; \
\
if (funcs->user_data) \
funcs->user_data->name = user_data; \
if (funcs->destroy) \
funcs->destroy->name = destroy; \
}
HB_PAINT_FUNCS_IMPLEMENT_CALLBACKS
#undef HB_PAINT_FUNC_IMPLEMENT
/**
* hb_paint_funcs_create:
*
* 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_t *
hb_paint_funcs_create ()
{
hb_paint_funcs_t *funcs;
if (unlikely (!(funcs = hb_object_create<hb_paint_funcs_t> ())))
return const_cast<hb_paint_funcs_t *> (&Null (hb_paint_funcs_t));
funcs->func = Null (hb_paint_funcs_t).func;
return funcs;
}
DEFINE_NULL_INSTANCE (hb_paint_funcs_t) =
{
HB_OBJECT_HEADER_STATIC,
{
#define HB_PAINT_FUNC_IMPLEMENT(name) hb_paint_##name##_nil,
HB_PAINT_FUNCS_IMPLEMENT_CALLBACKS
#undef HB_PAINT_FUNC_IMPLEMENT
}
};
/**
* hb_paint_funcs_get_empty:
*
* Fetches the singleton empty paint-functions structure.
*
* Return value: (transfer full): The empty paint-functions structure
*
* Since: 7.0.0
**/
hb_paint_funcs_t *
hb_paint_funcs_get_empty ()
{
return const_cast<hb_paint_funcs_t *> (&Null (hb_paint_funcs_t));
}
/**
* hb_paint_funcs_reference: (skip)
* @funcs: The paint-functions structure
*
* 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.
*
* Return value: The paint-functions structure
*
* Since: 7.0.0
*/
hb_paint_funcs_t *
hb_paint_funcs_reference (hb_paint_funcs_t *funcs)
{
return hb_object_reference (funcs);
}
/**
* hb_paint_funcs_destroy: (skip)
* @funcs: The paint-functions structure
*
* Decreases the reference count on a paint-functions structure.
*
* When the reference count reaches zero, the structure
* is destroyed, freeing all memory.
*
* Since: 7.0.0
*/
void
hb_paint_funcs_destroy (hb_paint_funcs_t *funcs)
{
if (!hb_object_destroy (funcs)) return;
if (funcs->destroy)
{
#define HB_PAINT_FUNC_IMPLEMENT(name) \
if (funcs->destroy->name) funcs->destroy->name (!funcs->user_data ? nullptr : funcs->user_data->name);
HB_PAINT_FUNCS_IMPLEMENT_CALLBACKS
#undef HB_PAINT_FUNC_IMPLEMENT
}
hb_free (funcs->destroy);
hb_free (funcs->user_data);
hb_free (funcs);
}
/**
* hb_paint_funcs_set_user_data: (skip)
* @funcs: The paint-functions structure
* @key: The user-data key
* @data: A pointer to the user data
* @destroy: (nullable): A callback to call when @data is not needed anymore
* @replace: Whether to replace an existing data with the same key
*
* Attaches a user-data key/data pair to the specified paint-functions structure.
*
* Return value: `true` if success, `false` otherwise
*
* Since: 7.0.0
**/
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)
{
return hb_object_set_user_data (funcs, key, data, destroy, replace);
}
/**
* hb_paint_funcs_get_user_data: (skip)
* @funcs: The paint-functions structure
* @key: The user-data key to query
*
* Fetches the user-data associated with the specified key,
* attached to the specified paint-functions structure.
*
* Return value: (transfer none): A pointer to the user data
*
* Since: 7.0.0
**/
void *
hb_paint_funcs_get_user_data (const hb_paint_funcs_t *funcs,
hb_user_data_key_t *key)
{
return hb_object_get_user_data (funcs, key);
}
/**
* hb_paint_funcs_make_immutable:
* @funcs: The paint-functions structure
*
* 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
*/
void
hb_paint_funcs_make_immutable (hb_paint_funcs_t *funcs)
{
if (hb_object_is_immutable (funcs))
return;
hb_object_make_immutable (funcs);
}
/**
* hb_paint_funcs_is_immutable:
* @funcs: The paint-functions structure
*
* Tests whether a paint-functions structure is immutable.
*
* Return value: `true` if @funcs is immutable, `false` otherwise
*
* Since: 7.0.0
*/
hb_bool_t
hb_paint_funcs_is_immutable (hb_paint_funcs_t *funcs)
{
return hb_object_is_immutable (funcs);
}
/**
* hb_color_line_get_color_stops:
* @color_line: a #hb_color_line_t object
* @start: the index of the first color stop to return
* @count: (inout) (optional): Input = the maximum number of feature tags to return;
* Output = the actual number of feature tags returned (may be zero)
* @color_stops: (out) (array length=count) (optional): Array of #hb_color_stop_t to populate
*
* 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.
*
* Return value: the total number of color stops in @color_line
*
* Since: 7.0.0
*/
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)
{
return color_line->get_color_stops (color_line,
color_line->data,
start, count,
color_stops,
color_line->get_color_stops_user_data);
}
/**
* hb_color_line_get_extend:
* @color_line: a #hb_color_line_t object
*
* Fetches the extend mode of the color line object.
*
* Return value: the extend mode of @color_line
*
* Since: 7.0.0
*/
hb_paint_extend_t
hb_color_line_get_extend (hb_color_line_t *color_line)
{
return color_line->get_extend (color_line,
color_line->data,
color_line->get_extend_user_data);
}
/**
* hb_paint_push_transform:
* @funcs: paint functions
* @paint_data: associated data passed by the caller
* @xx: xx component of the transform matrix
* @yx: yx component of the transform matrix
* @xy: xy component of the transform matrix
* @yy: yy component of the transform matrix
* @dx: dx component of the transform matrix
* @dy: dy component of the transform matrix
*
* Perform a "push-transform" paint operation.
*
* Since: 7.0.0
*/
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)
{
funcs->push_transform (paint_data, xx, yx, xy, yy, dx, dy);
}
/**
* hb_paint_push_font_transform:
* @funcs: paint functions
* @paint_data: associated data passed by the caller
* @font: a font
*
* Push the transform reflecting the font's scale and slant
* settings onto the paint functions.
*
* Since: 11.0.0
*/
void
hb_paint_push_font_transform (hb_paint_funcs_t *funcs, void *paint_data,
const hb_font_t *font)
{
funcs->push_font_transform (paint_data, font);
}
/**
* hb_paint_push_inverse_font_transform:
* @funcs: paint functions
* @paint_data: associated data passed by the caller
* @font: a font
*
* Push the inverse of the transform reflecting the font's
* scale and slant settings onto the paint functions.
*
* Since: 11.0.0
*/
void
hb_paint_push_inverse_font_transform (hb_paint_funcs_t *funcs, void *paint_data,
const hb_font_t *font)
{
funcs->push_inverse_font_transform (paint_data, font);
}
/**
* hb_paint_pop_transform:
* @funcs: paint functions
* @paint_data: associated data passed by the caller
*
* Perform a "pop-transform" paint operation.
*
* Since: 7.0.0
*/
void
hb_paint_pop_transform (hb_paint_funcs_t *funcs, void *paint_data)
{
funcs->pop_transform (paint_data);
}
/**
* hb_paint_color_glyph:
* @funcs: paint functions
* @paint_data: associated data passed by the caller
* @glyph: the glyph ID
* @font: the font
*
* Perform a "color-glyph" paint operation.
*
* Since: 8.2.0
*/
hb_bool_t
hb_paint_color_glyph (hb_paint_funcs_t *funcs, void *paint_data,
hb_codepoint_t glyph,
hb_font_t *font)
{
return funcs->color_glyph (paint_data, glyph, font);
}
/**
* hb_paint_push_clip_glyph:
* @funcs: paint functions
* @paint_data: associated data passed by the caller
* @glyph: the glyph ID
* @font: the font
*
* Perform a "push-clip-glyph" paint operation.
*
* Since: 7.0.0
*/
void
hb_paint_push_clip_glyph (hb_paint_funcs_t *funcs, void *paint_data,
hb_codepoint_t glyph,
hb_font_t *font)
{
funcs->push_clip_glyph (paint_data, glyph, font);
}
/**
* hb_paint_push_clip_rectangle:
* @funcs: paint functions
* @paint_data: associated data passed by the caller
* @xmin: min X for the rectangle
* @ymin: min Y for the rectangle
* @xmax: max X for the rectangle
* @ymax: max Y for the rectangle
*
* Perform a "push-clip-rect" paint operation.
*
* Since: 7.0.0
*/
void
hb_paint_push_clip_rectangle (hb_paint_funcs_t *funcs, void *paint_data,
float xmin, float ymin, float xmax, float ymax)
{
funcs->push_clip_rectangle (paint_data, xmin, ymin, xmax, ymax);
}
/**
* hb_paint_push_clip_path_start:
* @funcs: paint functions
* @paint_data: associated data passed by the caller
* @draw_data: (out) (nullable): location to receive the draw data
* the caller should pass alongside the returned draw funcs.
*
* Begin clipping to an arbitrary path. Returns an
* #hb_draw_funcs_t owned by the backend (the caller must not
* free it) that the caller uses to emit the clip outline via
* hb_draw_*() calls, using the returned @draw_data as the
* draw data. The returned draw funcs and draw data are only
* valid until the matching hb_paint_push_clip_path_end() call;
* no other paint calls should be made between start and end
* except hb_draw_*() on the returned funcs. Finish the path
* with hb_paint_push_clip_path_end(); pop the clip later
* with hb_paint_pop_clip().
*
* Usage:
*
* |[<!-- language="plain" -->
* hb_draw_funcs_t *df = hb_paint_push_clip_path_start (pf, pd, &dd);
* hb_draw_move_to (df, dd, NULL, ...);
* hb_draw_line_to (df, dd, NULL, ...);
* ...
* hb_draw_close_path (df, dd, NULL);
* hb_paint_push_clip_path_end (pf, pd);
* /* paint ops here are clipped to the emitted path */
* hb_paint_pop_clip (pf, pd);
* ]|
*
* Return value: (transfer none): draw funcs that accumulate
* the clip path, or `NULL` if the backend does not implement
* arbitrary-path clipping.
*
* Since: 14.2.0
*/
hb_draw_funcs_t *
hb_paint_push_clip_path_start (hb_paint_funcs_t *funcs,
void *paint_data,
void **draw_data)
{
void *scratch = nullptr;
if (!draw_data) draw_data = &scratch;
return funcs->push_clip_path_start (paint_data, draw_data);
}
/**
* hb_paint_push_clip_path_end:
* @funcs: paint functions
* @paint_data: associated data passed by the caller
*
* Signal that the arbitrary-clip path started by
* hb_paint_push_clip_path_start() is fully drawn. The
* accumulated path now acts as a clip on the paint context
* until a matching hb_paint_pop_clip() call.
*
* Since: 14.2.0
*/
void
hb_paint_push_clip_path_end (hb_paint_funcs_t *funcs, void *paint_data)
{
funcs->push_clip_path_end (paint_data);
}
/**
* hb_paint_pop_clip:
* @funcs: paint functions
* @paint_data: associated data passed by the caller
*
* Perform a "pop-clip" paint operation.
*
* Since: 7.0.0
*/
void
hb_paint_pop_clip (hb_paint_funcs_t *funcs, void *paint_data)
{
funcs->pop_clip (paint_data);
}
/**
* hb_paint_color:
* @funcs: paint functions
* @paint_data: associated data passed by the caller
* @is_foreground: whether the color is the foreground
* @color: The color to use
*
* Perform a "color" paint operation.
*
* Since: 7.0.0
*/
void
hb_paint_color (hb_paint_funcs_t *funcs, void *paint_data,
hb_bool_t is_foreground,
hb_color_t color)
{
funcs->color (paint_data, is_foreground, color);
}
/**
* hb_paint_image:
* @funcs: paint functions
* @paint_data: associated data passed by the caller
* @image: image data
* @width: width of the raster image in pixels, or 0
* @height: height of the raster image in pixels, or 0
* @format: the image format as a tag
* @slant: Deprecated. set to 0.0
* @extents: (nullable): the extents of the glyph
*
* Perform a "image" paint operation.
*
* Since: 7.0.0
*/
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,
HB_UNUSED float slant,
hb_glyph_extents_t *extents)
{
funcs->image (paint_data, image, width, height, format, 0.f, extents);
}
/**
* hb_paint_linear_gradient:
* @funcs: paint functions
* @paint_data: associated data passed by the caller
* @color_line: Color information for the gradient
* @x0: X coordinate of the first point
* @y0: Y coordinate of the first point
* @x1: X coordinate of the second point
* @y1: Y coordinate of the second point
* @x2: X coordinate of the third point
* @y2: Y coordinate of the third point
*
* Perform a "linear-gradient" paint operation.
*
* Since: 7.0.0
*/
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)
{
funcs->linear_gradient (paint_data, color_line, x0, y0, x1, y1, x2, y2);
}
/**
* hb_paint_radial_gradient:
* @funcs: paint functions
* @paint_data: associated data passed by the caller
* @color_line: Color information for the gradient
* @x0: X coordinate of the first circle's center
* @y0: Y coordinate of the first circle's center
* @r0: radius of the first circle
* @x1: X coordinate of the second circle's center
* @y1: Y coordinate of the second circle's center
* @r1: radius of the second circle
*
* Perform a "radial-gradient" paint operation.
*
* Since: 7.0.0
*/
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)
{
funcs->radial_gradient (paint_data, color_line, x0, y0, r0, x1, y1, r1);
}
/**
* hb_paint_sweep_gradient:
* @funcs: paint functions
* @paint_data: associated data passed by the caller
* @color_line: Color information for the gradient
* @x0: X coordinate of the circle's center
* @y0: Y coordinate of the circle's center
* @start_angle: the start angle
* @end_angle: the end angle
*
* Perform a "sweep-gradient" paint operation.
*
* Since: 7.0.0
*/
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)
{
funcs->sweep_gradient (paint_data, color_line, x0, y0, start_angle, end_angle);
}
/**
* hb_paint_push_group:
* @funcs: paint functions
* @paint_data: associated data passed by the caller
*
* Perform a "push-group" paint operation.
*
* Since: 7.0.0
*/
void
hb_paint_push_group (hb_paint_funcs_t *funcs, void *paint_data)
{
funcs->push_group (paint_data);
}
/**
* hb_paint_push_group_for:
* @funcs: paint functions
* @paint_data: associated data passed by the caller
* @mode: the compositing mode that will be used when the group is popped
*
* Perform a "push-group" paint operation, with the compositing
* mode known in advance. By default, this calls
* hb_paint_push_group().
*
* Since: 14.2.0
*/
void
hb_paint_push_group_for (hb_paint_funcs_t *funcs, void *paint_data,
hb_paint_composite_mode_t mode)
{
funcs->push_group_for (paint_data, mode);
}
/**
* hb_paint_pop_group:
* @funcs: paint functions
* @paint_data: associated data passed by the caller
* @mode: the compositing mode to use
*
* Perform a "pop-group" paint operation.
*
* Since: 7.0.0
*/
void
hb_paint_pop_group (hb_paint_funcs_t *funcs, void *paint_data,
hb_paint_composite_mode_t mode)
{
funcs->pop_group (paint_data, mode);
}
/**
* hb_paint_custom_palette_color:
* @funcs: paint functions.
* @paint_data: associated data passed by the caller.
* @color_index: color index to fetch.
* @color: (out): fetched color.
*
* Gets the custom palette override color for @color_index.
*
* Return value: `true` if a custom color is provided, `false` otherwise.
*
* Since: 7.0.0
*/
hb_bool_t
hb_paint_custom_palette_color (hb_paint_funcs_t *funcs, void *paint_data,
unsigned int color_index,
hb_color_t *color)
{
return funcs->custom_palette_color (paint_data, color_index, color);
}
/**
* hb_paint_reduce_linear_anchors:
* @x0: x coordinate of P0 (color stop 0).
* @y0: y coordinate of P0 (color stop 0).
* @x1: x coordinate of P1 (color stop 1).
* @y1: y coordinate of P1 (color stop 1).
* @x2: x coordinate of P2 (rotation reference).
* @y2: y coordinate of P2 (rotation reference).
* @xx0: (out): x coordinate of the resulting axis start.
* @yy0: (out): y coordinate of the resulting axis start.
* @xx1: (out): x coordinate of the resulting axis end.
* @yy1: (out): y coordinate of the resulting axis end.
*
* Reduces a COLRv1 linear gradient's 3-anchor spec (P0=color
* stop 0, P1=color stop 1, P2=rotation reference) to the
* 2-point axis (P0, P1') used by SVG / cairo / most software
* renderers. P1' is the foot of P1 on the line through P0
* perpendicular to (P2 - P0); the resulting axis is the
* gradient's actual direction (perpendicular to the rotation
* line). Degenerate (P0 == P2) passes through unchanged.
*
* Since: 14.2.0
**/
void
hb_paint_reduce_linear_anchors (float x0, float y0,
float x1, float y1,
float x2, float y2,
float *xx0, float *yy0,
float *xx1, float *yy1)
{
float q2x = x2 - x0, q2y = y2 - y0;
float s = q2x * q2x + q2y * q2y;
if (s < 1e-6f)
{
*xx0 = x0; *yy0 = y0;
*xx1 = x1; *yy1 = y1;
return;
}
float q1x = x1 - x0, q1y = y1 - y0;
float k = (q2x * q1x + q2y * q1y) / s;
*xx0 = x0;
*yy0 = y0;
*xx1 = x1 - k * q2x;
*yy1 = y1 - k * q2y;
}
/**
* hb_paint_normalize_color_line:
* @stops: (array length=len) (inout): color stops.
* @len: number of stops.
* @min: (out): original minimum offset.
* @max: (out): original maximum offset.
*
* Sorts @stops by offset and rescales offsets into [0, 1] in
* place. Writes the original (min, max) to @min / @max so the
* caller can shift the gradient geometry (axis endpoints for
* linear, centers+radii for radial, start+end angles for sweep)
* to keep the rendered gradient visually unchanged after the
* rescale. Empty input is safe: both out-parameters set to 0.
*
* Since: 14.2.0
**/
void
hb_paint_normalize_color_line (hb_color_stop_t *stops,
unsigned int len,
float *min,
float *max)
{
if (unlikely (!len))
{
*min = *max = 0.f;
return;
}
hb_array_t<hb_color_stop_t> (stops, len)
.qsort ([] (const hb_color_stop_t &a, const hb_color_stop_t &b) {
return a.offset < b.offset;
});
float mn = stops[0].offset, mx = stops[0].offset;
for (unsigned i = 1; i < len; i++)
{
mn = hb_min (mn, stops[i].offset);
mx = hb_max (mx, stops[i].offset);
}
if (mn != mx)
for (unsigned i = 0; i < len; i++)
stops[i].offset = (stops[i].offset - mn) / (mx - mn);
*min = mn;
*max = mx;
}
/**
* hb_paint_sweep_gradient_tiles:
* @stops: (array length=n_stops) (inout): color stops (sorted, offsets in [0,1]).
* @n_stops: number of stops.
* @extend: extend mode.
* @start_angle: sweep start angle, in radians.
* @end_angle: sweep end angle, in radians.
* @emit_patch: (scope call): callback invoked once per tile.
* @user_data: data passed to @emit_patch.
*
* Iterates the full 0..2π sweep produced by a color-stop list,
* invoking @emit_patch once per (start, end) angular segment.
* Handles #HB_PAINT_EXTEND_PAD, #HB_PAINT_EXTEND_REPEAT, and
* #HB_PAINT_EXTEND_REFLECT. Stops must be pre-sorted by
* offset; use hb_paint_normalize_color_line() first if they
* aren't.
*
* Since: 14.2.0
**/
void
hb_paint_sweep_gradient_tiles (hb_color_stop_t *stops,
unsigned int n_stops,
hb_paint_extend_t extend,
float start_angle,
float end_angle,
hb_paint_sweep_gradient_tile_func_t emit_patch,
void *user_data)
{
if (!n_stops) return;
if (start_angle == end_angle)
{
if (extend == HB_PAINT_EXTEND_PAD)
{
if (start_angle > 0.f)
emit_patch (0.f, stops[0].color, start_angle, stops[0].color, user_data);
if (end_angle < HB_2_PI)
emit_patch (end_angle, stops[n_stops - 1].color, HB_2_PI, stops[n_stops - 1].color, user_data);
}
return;
}
if (end_angle < start_angle)
{
float tmp = start_angle; start_angle = end_angle; end_angle = tmp;
for (unsigned i = 0; i < n_stops - 1 - i; i++)
{
hb_color_stop_t t = stops[i];
stops[i] = stops[n_stops - 1 - i];
stops[n_stops - 1 - i] = t;
}
for (unsigned i = 0; i < n_stops; i++)
stops[i].offset = 1.f - stops[i].offset;
}
/* Map stop offsets to angles. */
float angles_buf[16];
hb_color_t colors_buf[16];
float *angles = angles_buf;
hb_color_t *colors = colors_buf;
bool dynamic = false;
if (n_stops > 16)
{
angles = (float *) hb_malloc (sizeof (float) * n_stops);
colors = (hb_color_t *) hb_malloc (sizeof (hb_color_t) * n_stops);
if (!angles || !colors)
{
hb_free (angles);
hb_free (colors);
return;
}
dynamic = true;
}
for (unsigned i = 0; i < n_stops; i++)
{
angles[i] = start_angle + stops[i].offset * (end_angle - start_angle);
colors[i] = stops[i].color;
}
if (extend == HB_PAINT_EXTEND_PAD)
{
unsigned pos;
hb_color_t color0 = colors[0];
for (pos = 0; pos < n_stops; pos++)
{
if (angles[pos] >= 0)
{
if (pos > 0)
{
float f = (0.f - angles[pos - 1]) / (angles[pos] - angles[pos - 1]);
color0 = hb_color_lerp (colors[pos - 1], colors[pos], f);
}
break;
}
}
if (pos == n_stops)
{
color0 = colors[n_stops - 1];
emit_patch (0.f, color0, HB_2_PI, color0, user_data);
goto done;
}
emit_patch (0.f, color0, angles[pos], colors[pos], user_data);
for (pos++; pos < n_stops; pos++)
{
if (angles[pos] <= HB_2_PI)
emit_patch (angles[pos - 1], colors[pos - 1], angles[pos], colors[pos], user_data);
else
{
float f = (HB_2_PI - angles[pos - 1]) / (angles[pos] - angles[pos - 1]);
hb_color_t color1 = hb_color_lerp (colors[pos - 1], colors[pos], f);
emit_patch (angles[pos - 1], colors[pos - 1], HB_2_PI, color1, user_data);
break;
}
}
if (pos == n_stops)
{
color0 = colors[n_stops - 1];
emit_patch (angles[n_stops - 1], color0, HB_2_PI, color0, user_data);
goto done;
}
}
else
{
float span = angles[n_stops - 1] - angles[0];
if (fabsf (span) < 1e-6f)
goto done;
int k = 0;
if (angles[0] >= 0)
{
float ss = angles[0];
while (ss > 0)
{
if (span > 0) { ss -= span; k--; }
else { ss += span; k++; }
}
}
else
{
float ee = angles[n_stops - 1];
while (ee < 0)
{
if (span > 0) { ee += span; k++; }
else { ee -= span; k--; }
}
}
span = fabsf (span);
for (int l = k; l < 1000; l++)
{
for (unsigned i = 1; i < n_stops; i++)
{
float a0_l, a1_l;
hb_color_t col0, col1;
if ((l % 2 != 0) && (extend == HB_PAINT_EXTEND_REFLECT))
{
a0_l = angles[0] + angles[n_stops - 1] - angles[n_stops - i] + l * span;
a1_l = angles[0] + angles[n_stops - 1] - angles[n_stops - 1 - i] + l * span;
col0 = colors[n_stops - i];
col1 = colors[n_stops - 1 - i];
}
else
{
a0_l = angles[i - 1] + l * span;
a1_l = angles[i] + l * span;
col0 = colors[i - 1];
col1 = colors[i];
}
if (a1_l < 0.f) continue;
if (a0_l < 0.f)
{
float f = (0.f - a0_l) / (a1_l - a0_l);
hb_color_t c = hb_color_lerp (col0, col1, f);
emit_patch (0.f, c, a1_l, col1, user_data);
}
else if (a1_l >= HB_2_PI)
{
float f = (HB_2_PI - a0_l) / (a1_l - a0_l);
hb_color_t c = hb_color_lerp (col0, col1, f);
emit_patch (a0_l, col0, HB_2_PI, c, user_data);
goto done;
}
else
emit_patch (a0_l, col0, a1_l, col1, user_data);
}
}
}
done:
if (dynamic)
{
hb_free (angles);
hb_free (colors);
}
}
#endif