fill-and-stroke-alpha.c [plain text]
#include "cairo-test.h"
#define PAD 2
#define SIZE 10
static cairo_test_draw_function_t draw;
static const cairo_test_t test = {
"fill-and-stroke-alpha",
"Use a group to fill/stroke a path then blend the result with alpha onto the destination",
2 * SIZE + 4 * PAD, SIZE + 2 * PAD,
draw
};
typedef void (*path_func_t) (cairo_t *cr);
static void
rectangle (cairo_t *cr)
{
cairo_rectangle (cr, PAD, PAD, SIZE, SIZE);
}
static void
circle (cairo_t *cr)
{
cairo_arc (cr,
PAD + SIZE / 2, PAD + SIZE / 2,
SIZE / 2,
0, 2 * M_PI);
}
static void
fill_and_stroke_alpha (cairo_t *cr,
path_func_t path_func,
cairo_pattern_t *fill_pattern,
cairo_pattern_t *stroke_pattern,
double alpha)
{
cairo_push_group (cr);
{
(path_func) (cr);
cairo_set_source (cr, fill_pattern);
cairo_fill_preserve (cr);
cairo_set_source (cr, stroke_pattern);
cairo_stroke (cr);
}
cairo_pop_group_to_source (cr);
cairo_paint_with_alpha (cr, alpha);
}
static cairo_test_status_t
draw (cairo_t *cr, int width, int height)
{
cairo_pattern_t *blue;
cairo_pattern_t *red;
blue = cairo_pattern_create_rgb (0.0, 0.0, 1.0);
red = cairo_pattern_create_rgb (1.0, 0.0, 0.0);
cairo_test_paint_checkered (cr);
fill_and_stroke_alpha (cr, rectangle, blue, red, 0.5);
cairo_translate (cr, SIZE + 2 * PAD, 0);
fill_and_stroke_alpha (cr, circle, red, blue, 0.5);
cairo_pattern_destroy (blue);
cairo_pattern_destroy (red);
return CAIRO_TEST_SUCCESS;
}
int
main (void)
{
return cairo_test (&test);
}