fill-alpha-pattern.c [plain text]
#include "cairo-test.h"
#define SIZE 60
#define PAD 2
static cairo_test_status_t
draw (cairo_t *cr, int width, int height)
{
const double alpha = 1./3;
cairo_pattern_t *pattern;
int n;
pattern = cairo_pattern_create_linear (0, 0, width, height);
cairo_pattern_add_color_stop_rgb (pattern, 0, 1, 1, 0);
cairo_pattern_add_color_stop_rgb (pattern, 1, 1, 1, 1);
cairo_set_source (cr, pattern);
cairo_pattern_destroy (pattern);
cairo_paint (cr);
cairo_rectangle (cr, PAD, PAD, SIZE, SIZE);
cairo_set_source_rgba (cr, 1, 0, 0, alpha);
cairo_fill (cr);
cairo_translate (cr, SIZE + 2 * PAD, 0);
cairo_arc (cr, PAD + SIZE / 2., PAD + SIZE / 2., SIZE / 2., 0, 2 * M_PI);
cairo_set_source_rgba (cr, 0, 1, 0, alpha);
cairo_fill (cr);
cairo_translate (cr, 0, SIZE + 2 * PAD);
cairo_move_to (cr, PAD + SIZE / 2, PAD);
cairo_line_to (cr, PAD + SIZE, PAD + SIZE);
cairo_line_to (cr, PAD, PAD + SIZE);
cairo_set_source_rgba (cr, 0, 0, 1, alpha);
cairo_fill (cr);
cairo_translate (cr, -(SIZE + 2 * PAD) + SIZE/2., SIZE/2.);
for (n = 0; n < 5; n++) {
cairo_line_to (cr,
SIZE/2 * cos (2*n * 2*M_PI / 10),
SIZE/2 * sin (2*n * 2*M_PI / 10));
cairo_line_to (cr,
SIZE/4 * cos ((2*n+1)*2*M_PI / 10),
SIZE/4 * sin ((2*n+1)*2*M_PI / 10));
}
cairo_set_source_rgba (cr, 0, 0, 0, alpha);
cairo_fill (cr);
return CAIRO_TEST_SUCCESS;
}
CAIRO_TEST (fill_alpha_pattern,
"Tests using set_rgba();fill() over a linear gradient",
"fill, alpha",
NULL,
2*SIZE + 4*PAD, 2*SIZE + 4*PAD,
NULL, draw)