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harfbuzz/src/hb-cairo-utils.cc

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/*
* Copyright © 2022 Red Hat, Inc
* Copyright © 2021, 2022 Black Foundry
*
* 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.
*
* Google Author(s): Matthias Clasen
*/
#include "hb.hh"
#ifdef HAVE_CAIRO
#include "hb-cairo-utils.hh"
#include <cairo.h>
/* Some routines in this file were ported from BlackRenderer by Black Foundry.
* Used by permission to relicense to HarfBuzz license.
*
* https://github.com/BlackFoundryCom/black-renderer
*/
#define PREALLOCATED_COLOR_STOPS 16
typedef struct {
float r, g, b, a;
} hb_cairo_color_t;
static inline cairo_extend_t
hb_cairo_extend (hb_paint_extend_t extend)
{
switch (extend)
{
case HB_PAINT_EXTEND_PAD: return CAIRO_EXTEND_PAD;
case HB_PAINT_EXTEND_REPEAT: return CAIRO_EXTEND_REPEAT;
case HB_PAINT_EXTEND_REFLECT: return CAIRO_EXTEND_REFLECT;
default: break;
}
return CAIRO_EXTEND_PAD;
}
#ifdef CAIRO_HAS_PNG_FUNCTIONS
typedef struct
{
hb_blob_t *blob;
unsigned int offset;
} hb_cairo_read_blob_data_t;
static cairo_status_t
hb_cairo_read_blob (void *closure,
unsigned char *data,
unsigned int length)
{
hb_cairo_read_blob_data_t *r = (hb_cairo_read_blob_data_t *) closure;
const char *d;
unsigned int size;
d = hb_blob_get_data (r->blob, &size);
if (r->offset + length > size)
return CAIRO_STATUS_READ_ERROR;
memcpy (data, d + r->offset, length);
r->offset += length;
return CAIRO_STATUS_SUCCESS;
}
#endif
static const cairo_user_data_key_t *_hb_cairo_surface_blob_user_data_key = {0};
static void
_hb_cairo_destroy_blob (void *p)
{
hb_blob_destroy ((hb_blob_t *) p);
}
hb_bool_t
_hb_cairo_paint_glyph_image (hb_cairo_context_t *c,
hb_blob_t *blob,
unsigned width,
unsigned height,
hb_tag_t format,
float slant,
hb_glyph_extents_t *extents)
{
cairo_t *cr = c->cr;
if (!extents) /* SVG currently. */
return false;
cairo_surface_t *surface = nullptr;
#ifdef CAIRO_HAS_PNG_FUNCTIONS
if (format == HB_PAINT_IMAGE_FORMAT_PNG)
{
hb_cairo_read_blob_data_t r;
r.blob = blob;
r.offset = 0;
surface = cairo_image_surface_create_from_png_stream (hb_cairo_read_blob, &r);
/* For PNG, width,height can be unreliable, as is the case for NotoColorEmoji :(.
* Just pull them out of the surface. */
width = cairo_image_surface_get_width (surface);
height = cairo_image_surface_get_width (surface);
}
else
#endif
if (format == HB_PAINT_IMAGE_FORMAT_BGRA)
{
/* Byte-endian conversion. */
unsigned data_size = hb_blob_get_length (blob);
if (data_size < width * height * 4)
return false;
unsigned char *data;
#ifdef __BYTE_ORDER
if (__BYTE_ORDER == __BIG_ENDIAN)
{
data = (unsigned char *) hb_blob_get_data_writable (blob, nullptr);
if (!data)
return false;
unsigned count = width * height * 4;
for (unsigned i = 0; i < count; i += 4)
{
unsigned char b;
b = data[i];
data[i] = data[i+3];
data[i+3] = b;
b = data[i+1];
data[i+1] = data[i+2];
data[i+2] = b;
}
}
else
#endif
data = (unsigned char *) hb_blob_get_data (blob, nullptr);
surface = cairo_image_surface_create_for_data (data,
CAIRO_FORMAT_ARGB32,
width, height,
width * 4);
cairo_surface_set_user_data (surface,
_hb_cairo_surface_blob_user_data_key,
hb_blob_reference (blob),
_hb_cairo_destroy_blob);
}
if (!surface)
return false;
cairo_save (cr);
/* this clip is here to work around recording surface limitations */
cairo_rectangle (cr,
extents->x_bearing,
extents->y_bearing,
extents->width,
extents->height);
cairo_clip (cr);
cairo_pattern_t *pattern = cairo_pattern_create_for_surface (surface);
cairo_pattern_set_extend (pattern, CAIRO_EXTEND_PAD);
cairo_matrix_t matrix = {(double) width, 0, 0, (double) height, 0, 0};
cairo_pattern_set_matrix (pattern, &matrix);
/* Undo slant in the extents and apply it in the context. */
extents->width -= extents->height * slant;
extents->x_bearing -= extents->y_bearing * slant;
cairo_matrix_t cairo_matrix = {1., 0., (double) slant, 1., 0., 0.};
cairo_transform (cr, &cairo_matrix);
cairo_translate (cr, extents->x_bearing, extents->y_bearing);
cairo_scale (cr, extents->width, extents->height);
cairo_set_source (cr, pattern);
cairo_paint (cr);
cairo_pattern_destroy (pattern);
cairo_surface_destroy (surface);
cairo_restore (cr);
return true;
}
static void
_hb_cairo_reduce_anchors (float x0, float y0,
float x1, float y1,
float x2, float y2,
float *xx0, float *yy0,
float *xx1, float *yy1)
{
float q1x, q1y, q2x, q2y;
float s;
float k;
q2x = x2 - x0;
q2y = y2 - y0;
q1x = x1 - x0;
q1y = y1 - y0;
s = q2x * q2x + q2y * q2y;
if (s < 0.000001f)
{
*xx0 = x0; *yy0 = y0;
*xx1 = x1; *yy1 = y1;
return;
}
k = (q2x * q1x + q2y * q1y) / s;
*xx0 = x0;
*yy0 = y0;
*xx1 = x1 - k * q2x;
*yy1 = y1 - k * q2y;
}
static int
_hb_cairo_cmp_color_stop (const void *p1,
const void *p2)
{
const hb_color_stop_t *c1 = (const hb_color_stop_t *) p1;
const hb_color_stop_t *c2 = (const hb_color_stop_t *) p2;
if (c1->offset < c2->offset)
return -1;
else if (c1->offset > c2->offset)
return 1;
else
return 0;
}
static void
_hb_cairo_normalize_color_line (hb_color_stop_t *stops,
unsigned int len,
float *omin,
float *omax)
{
float min, max;
hb_qsort (stops, len, sizeof (hb_color_stop_t), _hb_cairo_cmp_color_stop);
min = max = stops[0].offset;
for (unsigned int i = 0; i < len; i++)
{
min = hb_min (min, stops[i].offset);
max = hb_max (max, stops[i].offset);
}
if (min != max)
{
for (unsigned int i = 0; i < len; i++)
stops[i].offset = (stops[i].offset - min) / (max - min);
}
*omin = min;
*omax = max;
}
static bool
_hb_cairo_get_color_stops (hb_cairo_context_t *c,
hb_color_line_t *color_line,
unsigned *count,
hb_color_stop_t **stops)
{
unsigned len = hb_color_line_get_color_stops (color_line, 0, nullptr, nullptr);
if (len > *count)
{
*stops = (hb_color_stop_t *) hb_malloc (len * sizeof (hb_color_stop_t));
if (unlikely (!stops))
return false;
}
hb_color_line_get_color_stops (color_line, 0, &len, *stops);
for (unsigned i = 0; i < len; i++)
if ((*stops)[i].is_foreground)
{
#ifdef HAVE_CAIRO_USER_SCALED_FONT_GET_FOREGROUND_SOURCE
double r, g, b, a;
cairo_pattern_t *foreground = cairo_user_scaled_font_get_foreground_source (c->scaled_font);
if (cairo_pattern_get_rgba (foreground, &r, &g, &b, &a) == CAIRO_STATUS_SUCCESS)
(*stops)[i].color = HB_COLOR (round (b * 255.), round (g * 255.), round (r * 255.),
round (a * hb_color_get_alpha ((*stops)[i].color)));
else
#endif
(*stops)[i].color = HB_COLOR (0, 0, 0, hb_color_get_alpha ((*stops)[i].color));
}
*count = len;
return true;
}
void
_hb_cairo_paint_linear_gradient (hb_cairo_context_t *c,
hb_color_line_t *color_line,
float x0, float y0,
float x1, float y1,
float x2, float y2)
{
cairo_t *cr = c->cr;
unsigned int len = PREALLOCATED_COLOR_STOPS;
hb_color_stop_t stops_[PREALLOCATED_COLOR_STOPS];
hb_color_stop_t *stops = stops_;
float xx0, yy0, xx1, yy1;
float xxx0, yyy0, xxx1, yyy1;
float min, max;
cairo_pattern_t *pattern;
if (unlikely (!_hb_cairo_get_color_stops (c, color_line, &len, &stops)))
return;
_hb_cairo_normalize_color_line (stops, len, &min, &max);
_hb_cairo_reduce_anchors (x0, y0, x1, y1, x2, y2, &xx0, &yy0, &xx1, &yy1);
xxx0 = xx0 + min * (xx1 - xx0);
yyy0 = yy0 + min * (yy1 - yy0);
xxx1 = xx0 + max * (xx1 - xx0);
yyy1 = yy0 + max * (yy1 - yy0);
pattern = cairo_pattern_create_linear ((double) xxx0, (double) yyy0, (double) xxx1, (double) yyy1);
cairo_pattern_set_extend (pattern, hb_cairo_extend (hb_color_line_get_extend (color_line)));
for (unsigned int i = 0; i < len; i++)
{
double r, g, b, a;
r = hb_color_get_red (stops[i].color) / 255.;
g = hb_color_get_green (stops[i].color) / 255.;
b = hb_color_get_blue (stops[i].color) / 255.;
a = hb_color_get_alpha (stops[i].color) / 255.;
cairo_pattern_add_color_stop_rgba (pattern, (double) stops[i].offset, r, g, b, a);
}
cairo_set_source (cr, pattern);
cairo_paint (cr);
cairo_pattern_destroy (pattern);
if (stops != stops_)
hb_free (stops);
}
void
_hb_cairo_paint_radial_gradient (hb_cairo_context_t *c,
hb_color_line_t *color_line,
float x0, float y0, float r0,
float x1, float y1, float r1)
{
cairo_t *cr = c->cr;
unsigned int len = PREALLOCATED_COLOR_STOPS;
hb_color_stop_t stops_[PREALLOCATED_COLOR_STOPS];
hb_color_stop_t *stops = stops_;
float min, max;
float xx0, yy0, xx1, yy1;
float rr0, rr1;
cairo_pattern_t *pattern;
if (unlikely (!_hb_cairo_get_color_stops (c, color_line, &len, &stops)))
return;
_hb_cairo_normalize_color_line (stops, len, &min, &max);
xx0 = x0 + min * (x1 - x0);
yy0 = y0 + min * (y1 - y0);
xx1 = x0 + max * (x1 - x0);
yy1 = y0 + max * (y1 - y0);
rr0 = r0 + min * (r1 - r0);
rr1 = r0 + max * (r1 - r0);
pattern = cairo_pattern_create_radial ((double) xx0, (double) yy0, (double) rr0, (double) xx1, (double) yy1, (double) rr1);
cairo_pattern_set_extend (pattern, hb_cairo_extend (hb_color_line_get_extend (color_line)));
for (unsigned int i = 0; i < len; i++)
{
double r, g, b, a;
r = hb_color_get_red (stops[i].color) / 255.;
g = hb_color_get_green (stops[i].color) / 255.;
b = hb_color_get_blue (stops[i].color) / 255.;
a = hb_color_get_alpha (stops[i].color) / 255.;
cairo_pattern_add_color_stop_rgba (pattern, (double) stops[i].offset, r, g, b, a);
}
cairo_set_source (cr, pattern);
cairo_paint (cr);
cairo_pattern_destroy (pattern);
if (stops != stops_)
hb_free (stops);
}
typedef struct {
float x, y;
} hb_cairo_point_t;
static inline float
_hb_cairo_interpolate (float f0, float f1, float f)
{
return f0 + f * (f1 - f0);
}
static inline void
_hb_cairo_premultiply (hb_cairo_color_t *c)
{
c->r *= c->a;
c->g *= c->a;
c->b *= c->a;
}
static inline void
_hb_cairo_unpremultiply (hb_cairo_color_t *c)
{
if (c->a != 0.f)
{
c->r /= c->a;
c->g /= c->a;
c->b /= c->a;
}
}
static void
_hb_cairo_interpolate_colors (hb_cairo_color_t *c0, hb_cairo_color_t *c1, float k, hb_cairo_color_t *c)
{
// According to the COLR specification, gradients
// should be interpolated in premultiplied form
_hb_cairo_premultiply (c0);
_hb_cairo_premultiply (c1);
c->r = c0->r + k * (c1->r - c0->r);
c->g = c0->g + k * (c1->g - c0->g);
c->b = c0->b + k * (c1->b - c0->b);
c->a = c0->a + k * (c1->a - c0->a);
_hb_cairo_unpremultiply (c);
}
static inline float
_hb_cairo_dot (hb_cairo_point_t p, hb_cairo_point_t q)
{
return p.x * q.x + p.y * q.y;
}
static inline hb_cairo_point_t
_hb_cairo_normalize (hb_cairo_point_t p)
{
float len = sqrtf (_hb_cairo_dot (p, p));
return hb_cairo_point_t { p.x / len, p.y / len };
}
static inline hb_cairo_point_t
_hb_cairo_sum (hb_cairo_point_t p, hb_cairo_point_t q)
{
return hb_cairo_point_t { p.x + q.x, p.y + q.y };
}
static inline hb_cairo_point_t
_hb_cairo_difference (hb_cairo_point_t p, hb_cairo_point_t q)
{
return hb_cairo_point_t { p.x - q.x, p.y - q.y };
}
static inline hb_cairo_point_t
_hb_cairo_scale (hb_cairo_point_t p, float f)
{
return hb_cairo_point_t { p.x * f, p.y * f };
}
typedef struct {
hb_cairo_point_t center, p0, c0, c1, p1;
hb_cairo_color_t color0, color1;
} hb_cairo_patch_t;
static void
_hb_cairo_add_patch (cairo_pattern_t *pattern, hb_cairo_point_t *center, hb_cairo_patch_t *p)
{
cairo_mesh_pattern_begin_patch (pattern);
cairo_mesh_pattern_move_to (pattern, (double) center->x, (double) center->y);
cairo_mesh_pattern_line_to (pattern, (double) p->p0.x, (double) p->p0.y);
cairo_mesh_pattern_curve_to (pattern,
(double) p->c0.x, (double) p->c0.y,
(double) p->c1.x, (double) p->c1.y,
(double) p->p1.x, (double) p->p1.y);
cairo_mesh_pattern_line_to (pattern, (double) center->x, (double) center->y);
cairo_mesh_pattern_set_corner_color_rgba (pattern, 0,
(double) p->color0.r,
(double) p->color0.g,
(double) p->color0.b,
(double) p->color0.a);
cairo_mesh_pattern_set_corner_color_rgba (pattern, 1,
(double) p->color0.r,
(double) p->color0.g,
(double) p->color0.b,
(double) p->color0.a);
cairo_mesh_pattern_set_corner_color_rgba (pattern, 2,
(double) p->color1.r,
(double) p->color1.g,
(double) p->color1.b,
(double) p->color1.a);
cairo_mesh_pattern_set_corner_color_rgba (pattern, 3,
(double) p->color1.r,
(double) p->color1.g,
(double) p->color1.b,
(double) p->color1.a);
cairo_mesh_pattern_end_patch (pattern);
}
#define MAX_ANGLE (HB_PI / 8.f)
static void
_hb_cairo_add_sweep_gradient_patches1 (float cx, float cy, float radius,
float a0, hb_cairo_color_t *c0,
float a1, hb_cairo_color_t *c1,
cairo_pattern_t *pattern)
{
hb_cairo_point_t center = hb_cairo_point_t { cx, cy };
int num_splits;
hb_cairo_point_t p0;
hb_cairo_color_t color0, color1;
num_splits = ceilf (fabsf (a1 - a0) / MAX_ANGLE);
p0 = hb_cairo_point_t { cosf (a0), sinf (a0) };
color0 = *c0;
for (int a = 0; a < num_splits; a++)
{
float k = (a + 1.) / num_splits;
float angle1;
hb_cairo_point_t p1;
hb_cairo_point_t A, U;
hb_cairo_point_t C0, C1;
hb_cairo_patch_t patch;
angle1 = _hb_cairo_interpolate (a0, a1, k);
_hb_cairo_interpolate_colors (c0, c1, k, &color1);
patch.color0 = color0;
patch.color1 = color1;
p1 = hb_cairo_point_t { cosf (angle1), sinf (angle1) };
patch.p0 = _hb_cairo_sum (center, _hb_cairo_scale (p0, radius));
patch.p1 = _hb_cairo_sum (center, _hb_cairo_scale (p1, radius));
A = _hb_cairo_normalize (_hb_cairo_sum (p0, p1));
U = hb_cairo_point_t { -A.y, A.x };
C0 = _hb_cairo_sum (A, _hb_cairo_scale (U, _hb_cairo_dot (_hb_cairo_difference (p0, A), p0) / _hb_cairo_dot (U, p0)));
C1 = _hb_cairo_sum (A, _hb_cairo_scale (U, _hb_cairo_dot (_hb_cairo_difference (p1, A), p1) / _hb_cairo_dot (U, p1)));
patch.c0 = _hb_cairo_sum (center, _hb_cairo_scale (_hb_cairo_sum (C0, _hb_cairo_scale (_hb_cairo_difference (C0, p0), 0.33333f)), radius));
patch.c1 = _hb_cairo_sum (center, _hb_cairo_scale (_hb_cairo_sum (C1, _hb_cairo_scale (_hb_cairo_difference (C1, p1), 0.33333f)), radius));
_hb_cairo_add_patch (pattern, &center, &patch);
p0 = p1;
color0 = color1;
}
}
static void
_hb_cairo_add_sweep_gradient_patches (hb_color_stop_t *stops,
unsigned int n_stops,
cairo_extend_t extend,
float cx, float cy,
float radius,
float start_angle,
float end_angle,
cairo_pattern_t *pattern)
{
float angles_[PREALLOCATED_COLOR_STOPS];
float *angles = angles_;
hb_cairo_color_t colors_[PREALLOCATED_COLOR_STOPS];
hb_cairo_color_t *colors = colors_;
hb_cairo_color_t color0, color1;
if (start_angle == end_angle)
{
if (extend == CAIRO_EXTEND_PAD)
{
hb_cairo_color_t c;
if (start_angle > 0)
{
c.r = hb_color_get_red (stops[0].color) / 255.;
c.g = hb_color_get_green (stops[0].color) / 255.;
c.b = hb_color_get_blue (stops[0].color) / 255.;
c.a = hb_color_get_alpha (stops[0].color) / 255.;
_hb_cairo_add_sweep_gradient_patches1 (cx, cy, radius,
0., &c,
start_angle, &c,
pattern);
}
if (end_angle < HB_2_PI)
{
c.r = hb_color_get_red (stops[n_stops - 1].color) / 255.;
c.g = hb_color_get_green (stops[n_stops - 1].color) / 255.;
c.b = hb_color_get_blue (stops[n_stops - 1].color) / 255.;
c.a = hb_color_get_alpha (stops[n_stops - 1].color) / 255.;
_hb_cairo_add_sweep_gradient_patches1 (cx, cy, radius,
end_angle, &c,
HB_2_PI, &c,
pattern);
}
}
return;
}
assert (start_angle != end_angle);
/* handle directions */
if (end_angle < start_angle)
{
hb_swap (start_angle, end_angle);
for (unsigned i = 0; i < n_stops - 1 - i; i++)
hb_swap (stops[i], stops[n_stops - 1 - i]);
for (unsigned i = 0; i < n_stops; i++)
stops[i].offset = 1 - stops[i].offset;
}
if (n_stops > PREALLOCATED_COLOR_STOPS)
{
angles = (float *) hb_malloc (sizeof (float) * n_stops);
colors = (hb_cairo_color_t *) hb_malloc (sizeof (hb_cairo_color_t) * n_stops);
if (unlikely (!angles || !colors))
{
hb_free (angles);
hb_free (colors);
return;
}
}
for (unsigned i = 0; i < n_stops; i++)
{
angles[i] = start_angle + stops[i].offset * (end_angle - start_angle);
colors[i].r = hb_color_get_red (stops[i].color) / 255.;
colors[i].g = hb_color_get_green (stops[i].color) / 255.;
colors[i].b = hb_color_get_blue (stops[i].color) / 255.;
colors[i].a = hb_color_get_alpha (stops[i].color) / 255.;
}
if (extend == CAIRO_EXTEND_PAD)
{
unsigned pos;
color0 = colors[0];
for (pos = 0; pos < n_stops; pos++)
{
if (angles[pos] >= 0)
{
if (pos > 0)
{
float k = (0 - angles[pos - 1]) / (angles[pos] - angles[pos - 1]);
_hb_cairo_interpolate_colors (&colors[pos-1], &colors[pos], k, &color0);
}
break;
}
}
if (pos == n_stops)
{
/* everything is below 0 */
color0 = colors[n_stops-1];
_hb_cairo_add_sweep_gradient_patches1 (cx, cy, radius,
0., &color0,
HB_2_PI, &color0,
pattern);
goto done;
}
_hb_cairo_add_sweep_gradient_patches1 (cx, cy, radius,
0., &color0,
angles[pos], &colors[pos],
pattern);
for (pos++; pos < n_stops; pos++)
{
if (angles[pos] <= HB_2_PI)
{
_hb_cairo_add_sweep_gradient_patches1 (cx, cy, radius,
angles[pos - 1], &colors[pos-1],
angles[pos], &colors[pos],
pattern);
}
else
{
float k = (HB_2_PI - angles[pos - 1]) / (angles[pos] - angles[pos - 1]);
_hb_cairo_interpolate_colors (&colors[pos - 1], &colors[pos], k, &color1);
_hb_cairo_add_sweep_gradient_patches1 (cx, cy, radius,
angles[pos - 1], &colors[pos - 1],
HB_2_PI, &color1,
pattern);
break;
}
}
if (pos == n_stops)
{
/* everything is below 2*M_PI */
color0 = colors[n_stops - 1];
_hb_cairo_add_sweep_gradient_patches1 (cx, cy, radius,
angles[n_stops - 1], &color0,
HB_2_PI, &color0,
pattern);
goto done;
}
}
else
{
int k;
float span;
span = angles[n_stops - 1] - angles[0];
k = 0;
if (angles[0] >= 0)
{
float ss = angles[0];
while (ss > 0)
{
if (span > 0)
{
ss -= span;
k--;
}
else
{
ss += span;
k++;
}
}
}
else if (angles[0] < 0)
{
float ee = angles[n_stops - 1];
while (ee < 0)
{
if (span > 0)
{
ee += span;
k++;
}
else
{
ee -= span;
k--;
}
}
}
//assert (angles[0] + k * span <= 0 && 0 < angles[n_stops - 1] + k * span);
span = fabs (span);
for (signed l = k; l < 1000; l++)
{
for (unsigned i = 1; i < n_stops; i++)
{
float a0, a1;
hb_cairo_color_t *c0, *c1;
if ((l % 2 != 0) && (extend == CAIRO_EXTEND_REFLECT))
{
a0 = angles[0] + angles[n_stops - 1] - angles[n_stops - 1 - (i-1)] + l * span;
a1 = angles[0] + angles[n_stops - 1] - angles[n_stops - 1 - i] + l * span;
c0 = &colors[n_stops - 1 - (i - 1)];
c1 = &colors[n_stops - 1 - i];
}
else
{
a0 = angles[i-1] + l * span;
a1 = angles[i] + l * span;
c0 = &colors[i-1];
c1 = &colors[i];
}
if (a1 < 0)
continue;
if (a0 < 0)
{
hb_cairo_color_t color;
float f = (0 - a0)/(a1 - a0);
_hb_cairo_interpolate_colors (c0, c1, f, &color);
_hb_cairo_add_sweep_gradient_patches1 (cx, cy, radius,
0, &color,
a1, c1,
pattern);
}
else if (a1 >= HB_2_PI)
{
hb_cairo_color_t color;
float f = (HB_2_PI - a0)/(a1 - a0);
_hb_cairo_interpolate_colors (c0, c1, f, &color);
_hb_cairo_add_sweep_gradient_patches1 (cx, cy, radius,
a0, c0,
HB_2_PI, &color,
pattern);
goto done;
}
else
{
_hb_cairo_add_sweep_gradient_patches1 (cx, cy, radius,
a0, c0,
a1, c1,
pattern);
}
}
}
}
done:
if (angles != angles_)
hb_free (angles);
if (colors != colors_)
hb_free (colors);
}
void
_hb_cairo_paint_sweep_gradient (hb_cairo_context_t *c,
hb_color_line_t *color_line,
float cx, float cy,
float start_angle,
float end_angle)
{
cairo_t *cr = c->cr;
unsigned int len = PREALLOCATED_COLOR_STOPS;
hb_color_stop_t stops_[PREALLOCATED_COLOR_STOPS];
hb_color_stop_t *stops = stops_;
cairo_extend_t extend;
double x1, y1, x2, y2;
float max_x, max_y, radius;
cairo_pattern_t *pattern;
if (unlikely (!_hb_cairo_get_color_stops (c, color_line, &len, &stops)))
return;
hb_qsort (stops, len, sizeof (hb_color_stop_t), _hb_cairo_cmp_color_stop);
cairo_clip_extents (cr, &x1, &y1, &x2, &y2);
max_x = (float) hb_max ((x1 - (double) cx) * (x1 - (double) cx), (x2 - (double) cx) * (x2 - (double) cx));
max_y = (float) hb_max ((y1 - (double) cy) * (y1 - (double) cy), (y2 - (double) cy) * (y2 - (double) cy));
radius = sqrtf (max_x + max_y);
extend = hb_cairo_extend (hb_color_line_get_extend (color_line));
pattern = cairo_pattern_create_mesh ();
_hb_cairo_add_sweep_gradient_patches (stops, len, extend, cx, cy,
radius, start_angle, end_angle, pattern);
cairo_set_source (cr, pattern);
cairo_paint (cr);
cairo_pattern_destroy (pattern);
if (stops != stops_)
hb_free (stops);
}
#endif
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