cairo_surface_t *
_cairo_image_surface_create_from_pixbuf (GdkPixbuf *pixbuf)
{
cairo_surface_t *surface;
cairo_surface_metadata_t *metadata;
int width;
int height;
int p_stride;
int p_n_channels;
guchar *p_pixels;
int s_stride;
unsigned char *s_pixels;
int h, w;
guint32 pixel;
guchar r, g, b, a;
if (pixbuf == NULL)
return NULL;
g_object_get (G_OBJECT (pixbuf),
"width", &width,
"height", &height,
"rowstride", &p_stride,
"n-channels", &p_n_channels,
"pixels", &p_pixels,
NULL );
surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, width, height);
s_stride = cairo_image_surface_get_stride (surface);
s_pixels = _cairo_image_surface_flush_and_get_data (surface);
metadata = _cairo_image_surface_get_metadata (surface);
metadata->has_alpha = (p_n_channels == 4);
if (p_n_channels == 4) {
guchar *s_iter;
guchar *p_iter;
for (h = 0; h < height; h++) {
s_iter = s_pixels;
p_iter = p_pixels;
for (w = 0; w < width; w++) {
a = p_iter[3];
if (a == 0xff) {
pixel = CAIRO_RGBA_TO_UINT32 (p_iter[0], p_iter[1], p_iter[2], 0xff);
}
else if (a == 0) {
pixel = 0;
}
else {
r = _cairo_multiply_alpha (p_iter[0], a);
g = _cairo_multiply_alpha (p_iter[1], a);
b = _cairo_multiply_alpha (p_iter[2], a);
pixel = CAIRO_RGBA_TO_UINT32 (r, g, b, a);
}
memcpy (s_iter, &pixel, sizeof (guint32));
s_iter += 4;
p_iter += p_n_channels;
}
s_pixels += s_stride;
p_pixels += p_stride;
}
}
else {
guchar *s_iter;
guchar *p_iter;
for (h = 0; h < height; h++) {
s_iter = s_pixels;
p_iter = p_pixels;
for (w = 0; w < width; w++) {
pixel = CAIRO_RGBA_TO_UINT32 (p_iter[0], p_iter[1], p_iter[2], 0xff);
memcpy (s_iter, &pixel, sizeof (guint32));
s_iter += 4;
p_iter += p_n_channels;
}
s_pixels += s_stride;
p_pixels += p_stride;
}
}
cairo_surface_mark_dirty (surface);
return surface;
}