/*
* Copyright © 2022 Red Hat, Inc
*
* 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-cairo-utils.h"
#include <cairo.h>
#include <hb-ot.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include <assert.h>
#ifndef MIN
#define MIN(x,y) ((x) < (y) ? (x) : (y))
#endif
#ifndef MAX
#define MAX(x,y) ((x) > (y) ? (x) : (y))
#endif
typedef struct {
float r, g, b, a;
} color_t;
typedef struct {
cairo_t *cr;
hb_font_t *font;
hb_font_t *unscaled_font;
} paint_data_t;
static inline cairo_extend_t
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:;
}
return CAIRO_EXTEND_PAD;
}
void
hb_face_get_color (hb_face_t *face,
unsigned int palette_index,
unsigned int color_index,
float alpha,
float *r, float *g, float *b, float *a)
{
if (color_index == 0xffff)
{
/* foreground color */
*r = *g = *b = 0;
*a = alpha;
}
else
{
hb_color_t color;
unsigned int clen = 1;
if (hb_ot_color_palette_get_colors (face, palette_index, color_index, &clen, &color))
{
*r = hb_color_get_red (color) / 255.f;
*g = hb_color_get_green (color) / 255.f;
*b = hb_color_get_blue (color) / 255.f;
*a = (hb_color_get_alpha (color) / 255.f) * alpha;
}
else
{
*r = *g = *b = 0;
*a = alpha;
}
}
}
typedef struct
{
hb_blob_t *blob;
unsigned int offset;
} read_blob_data_t;
static cairo_status_t
read_blob (void *closure,
unsigned char *data,
unsigned int length)
{
read_blob_data_t *r = (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;
}
void
hb_cairo_paint_glyph_image (cairo_t *cr,
hb_font_t *font,
hb_blob_t *blob,
hb_tag_t format,
hb_glyph_extents_t *extents)
{
if (format != HB_PAINT_IMAGE_FORMAT_PNG || !extents)
return;
read_blob_data_t r;
r.blob = blob;
r.offset = 0;
cairo_surface_t *surface = cairo_image_surface_create_from_png_stream (read_blob, &r);
int width = cairo_image_surface_get_width (surface);
int height = cairo_image_surface_get_width (surface);
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);
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);
}
static void
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 = y1 - 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
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
normalize_color_line (hb_color_stop_t *stops,
unsigned int len,
float *omin,
float *omax)
{
float min, max;
qsort (stops, len, sizeof (hb_color_stop_t), cmp_color_stop);
min = max = stops[0].offset;
for (unsigned int i = 0; i < len; i++)
{
min = MIN (min, stops[i].offset);
max = 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;
}
void
hb_cairo_paint_linear_gradient (cairo_t *cr,
hb_font_t *font,
hb_color_line_t *color_line,
float x0, float y0,
float x1, float y1,
float x2, float y2)
{
hb_face_t *face = hb_font_get_face (font);
unsigned int len;
hb_color_stop_t *stops;
float xx0, yy0, xx1, yy1;
float xxx0, yyy0, xxx1, yyy1;
float min, max;
cairo_pattern_t *pattern;
len = hb_color_line_get_color_stops (color_line, 0, NULL, NULL);
stops = (hb_color_stop_t *) alloca (len * sizeof (hb_color_stop_t));
hb_color_line_get_color_stops (color_line, 0, &len, stops);
reduce_anchors (x0, y0, x1, y1, x2, y2, &xx0, &yy0, &xx1, &yy1);
normalize_color_line (stops, len, &min, &max);
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 (xxx0, yyy0, xxx1, yyy1);
cairo_pattern_set_extend (pattern, cairo_extend (hb_color_line_get_extend (color_line)));
for (unsigned int i = 0; i < len; i++)
{
float r, g, b, a;
hb_face_get_color (face, 0, stops[i].color_index, stops[i].alpha, &r, &g, &b, &a);
cairo_pattern_add_color_stop_rgba (pattern, stops[i].offset, r, g, b, a);
}
cairo_set_source (cr, pattern);
cairo_paint (cr);
cairo_pattern_destroy (pattern);
}
void
hb_cairo_paint_radial_gradient (cairo_t *cr,
hb_font_t *font,
hb_color_line_t *color_line,
float x0, float y0, float r0,
float x1, float y1, float r1)
{
hb_face_t *face = hb_font_get_face (font);
unsigned int len;
hb_color_stop_t *stops;
float min, max;
float xx0, yy0, xx1, yy1;
float rr0, rr1;
cairo_pattern_t *pattern;
len = hb_color_line_get_color_stops (color_line, 0, NULL, NULL);
stops = (hb_color_stop_t *) alloca (len * sizeof (hb_color_stop_t));
hb_color_line_get_color_stops (color_line, 0, &len, stops);
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 (xx0, yy0, rr0, xx1, yy1, rr1);
cairo_pattern_set_extend (pattern, cairo_extend (hb_color_line_get_extend (color_line)));
for (unsigned int i = 0; i < len; i++)
{
float r, g, b, a;
hb_face_get_color (face, 0, stops[i].color_index, stops[i].alpha, &r, &g, &b, &a);
cairo_pattern_add_color_stop_rgba (pattern, stops[i].offset, r, g, b, a);
}
cairo_set_source (cr, pattern);
cairo_paint (cr);
cairo_pattern_destroy (pattern);
}
typedef struct {
float x, y;
} Point;
static inline float
interpolate (float f0, float f1, float f)
{
return f0 + f * (f1 - f0);
}
static void
interpolate_colors (color_t *c0, color_t *c1, float k, color_t *c)
{
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);
}
static inline float
dot (Point p, Point q)
{
return p.x * q.x + p.y * q.y;
}
static inline Point
normalize (Point p)
{
float len = sqrt (dot (p, p));
return (Point) { p.x / len, p.y / len };
}
static inline Point
sum (Point p, Point q)
{
return (Point) { p.x + q.x, p.y + q.y };
}
static inline Point
difference (Point p, Point q)
{
return (Point) { p.x - q.x, p.y - q.y };
}
static inline Point
scale (Point p, float f)
{
return (Point) { p.x * f, p.y * f };
}
typedef struct {
Point center, p0, c0, c1, p1;
color_t color0, color1;
} Patch;
static void
add_patch (cairo_pattern_t *pattern, Point *center, Patch *p)
{
cairo_mesh_pattern_begin_patch (pattern);
cairo_mesh_pattern_move_to (pattern, center->x, center->y);
cairo_mesh_pattern_line_to (pattern, p->p0.x, p->p0.y);
cairo_mesh_pattern_curve_to (pattern,
p->c0.x, p->c0.y,
p->c1.x, p->c1.y,
p->p1.x, p->p1.y);
cairo_mesh_pattern_line_to (pattern, center->x, center->y);
cairo_mesh_pattern_set_corner_color_rgba (pattern, 0,
p->color0.r,
p->color0.g,
p->color0.b,
p->color0.a);
cairo_mesh_pattern_set_corner_color_rgba (pattern, 1,
p->color0.r,
p->color0.g,
p->color0.b,
p->color0.a);
cairo_mesh_pattern_set_corner_color_rgba (pattern, 2,
p->color1.r,
p->color1.g,
p->color1.b,
p->color1.a);
cairo_mesh_pattern_set_corner_color_rgba (pattern, 3,
p->color1.r,
p->color1.g,
p->color1.b,
p->color1.a);
cairo_mesh_pattern_end_patch (pattern);
}
#define MAX_ANGLE (M_PI / 8.)
static void
add_sweep_gradient_patches1 (float cx, float cy, float radius,
float a0, color_t *c0,
float a1, color_t *c1,
cairo_pattern_t *pattern)
{
Point center = (Point) { cx, cy };
int num_splits;
Point p0;
color_t color0, color1;
num_splits = ceilf (fabs (a1 - a0) / MAX_ANGLE);
p0 = (Point) { cosf (a0), sinf (a0) };
color0 = *c0;
for (int a = 0; a < num_splits; a++)
{
float k = (a + 1.) / num_splits;
float angle1;
Point p1;
Point A, U;
Point C0, C1;
Patch patch;
angle1 = interpolate (a0, a1, k);
interpolate_colors (c0, c1, k, &color1);
patch.color0 = color0;
patch.color1 = color1;
p1 = (Point) { cosf (angle1), sinf (angle1) };
patch.p0 = sum (center, scale (p0, radius));
patch.p1 = sum (center, scale (p1, radius));
A = normalize (sum (p0, p1));
U = (Point) { -A.y, A.x };
C0 = sum (A, scale (U, dot (difference (p0, A), p0) / dot (U, p0)));
C1 = sum (A, scale (U, dot (difference (p1, A), p1) / dot (U, p1)));
patch.c0 = sum (center, scale (sum (C0, scale (difference (C0, p0), 0.33333)), radius));
patch.c1 = sum (center, scale (sum (C1, scale (difference (C1, p1), 0.33333)), radius));
add_patch (pattern, ¢er, &patch);
p0 = p1;
color0 = color1;
}
}
static void
add_sweep_gradient_patches (hb_font_t *font,
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)
{
hb_face_t *face = hb_font_get_face (font);
float *angles;
color_t *colors;
color_t color0, color1;
if (start_angle == end_angle)
{
if (extend == CAIRO_EXTEND_PAD)
{
color_t c;
if (start_angle > 0)
{
hb_face_get_color (face, 0, stops[0].color_index, stops[0].alpha, &c.r, &c.g, &c.b, &c.a);
add_sweep_gradient_patches1 (cx, cy, radius,
0., &c,
start_angle, &c,
pattern);
}
if (end_angle < 2 * M_PI)
{
hb_face_get_color (face, 0, stops[n_stops-1].color_index, stops[n_stops-1].alpha, &c.r, &c.g, &c.b, &c.a);
add_sweep_gradient_patches1 (cx, cy, radius,
end_angle, &c,
2 * M_PI, &c,
pattern);
}
}
return;
}
assert (start_angle != end_angle);
/* handle directions */
if (end_angle < start_angle)
{
float angle = end_angle;
end_angle = start_angle;
start_angle = angle;
for (unsigned i = 0; i < n_stops - 1 - i; i++)
{
hb_color_stop_t stop = stops[i];
stops[i] = stops[n_stops - 1 - i];
stops[n_stops - 1 - i] = stop;
}
}
angles = alloca (sizeof (float) * n_stops);
colors = alloca (sizeof (color_t) * n_stops);
for (unsigned i = 0; i < n_stops; i++)
{
angles[i] = start_angle + stops[i].offset * (end_angle - start_angle);
hb_face_get_color (face, 0, stops[i].color_index, stops[i].alpha, &colors[i].r, &colors[i].g, &colors[i].b, &colors[i].a);
}
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]);
interpolate_colors (&colors[pos-1], &colors[pos], k, &color0);
}
break;
}
}
if (pos == n_stops)
{
/* everything is below 0 */
color0 = colors[n_stops-1];
add_sweep_gradient_patches1 (cx, cy, radius,
0., &color0,
2 * M_PI, &color0,
pattern);
return;
}
add_sweep_gradient_patches1 (cx, cy, radius,
0., &color0,
angles[pos], &colors[pos],
pattern);
for (pos++; pos < n_stops; pos++)
{
if (angles[pos] <= 2 * M_PI)
{
add_sweep_gradient_patches1 (cx, cy, radius,
angles[pos - 1], &colors[pos-1],
angles[pos], &colors[pos],
pattern);
}
else
{
float k = (2 * M_PI - angles[pos - 1]) / (angles[pos] - angles[pos - 1]);
interpolate_colors (&colors[pos - 1], &colors[pos], k, &color1);
add_sweep_gradient_patches1 (cx, cy, radius,
angles[pos - 1], &colors[pos - 1],
2 * M_PI, &color1,
pattern);
break;
}
}
if (pos == n_stops)
{
/* everything is below 2*M_PI */
color0 = colors[n_stops - 1];
add_sweep_gradient_patches1 (cx, cy, radius,
angles[n_stops - 1], &color0,
2 * M_PI, &color0,
pattern);
return;
}
}
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);
for (unsigned l = k; 1; l++)
{
for (unsigned i = 1; i < n_stops; i++)
{
float a0, a1;
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)
{
color_t color;
float f = (0 - a0)/(a1 - a0);
interpolate_colors (c0, c1, f, &color);
add_sweep_gradient_patches1 (cx, cy, radius,
0, &color,
a1, c1,
pattern);
}
else if (a1 >= 2 * M_PI)
{
color_t color;
float f = (2 * M_PI - a0)/(a1 - a0);
interpolate_colors (c0, c1, f, &color);
add_sweep_gradient_patches1 (cx, cy, radius,
a0, c0,
2 * M_PI, &color,
pattern);
goto done;
}
else
{
add_sweep_gradient_patches1 (cx, cy, radius,
a0, c0,
a1, c1,
pattern);
}
}
}
done: ;
}
}
void
hb_cairo_paint_sweep_gradient (cairo_t *cr,
hb_font_t *font,
hb_color_line_t *color_line,
float cx, float cy,
float start_angle,
float end_angle)
{
unsigned int len;
hb_color_stop_t *stops;
cairo_extend_t extend;
double x1, y1, x2, y2;
float max_x, max_y, radius;
cairo_pattern_t *pattern;
len = hb_color_line_get_color_stops (color_line, 0, NULL, NULL);
stops = alloca (len * sizeof (hb_color_stop_t));
hb_color_line_get_color_stops (color_line, 0, &len, stops);
qsort (stops, len, sizeof (hb_color_stop_t), cmp_color_stop);
cairo_clip_extents (cr, &x1, &y1, &x2, &y2);
max_x = MAX ((x1 - cx) * (x1 - cx), (x2 - cx) * (x2 - cx));
max_y = MAX ((y1 - cy) * (y1 - cy), (y2 - cy) * (y2 - cy));
radius = sqrt (max_x + max_y);
extend = cairo_extend (hb_color_line_get_extend (color_line));
pattern = cairo_pattern_create_mesh ();
add_sweep_gradient_patches (font, stops, len, extend, cx, cy,
radius, start_angle, end_angle, pattern);
cairo_set_source (cr, pattern);
cairo_paint (cr);
cairo_pattern_destroy (pattern);
}
