Support on-the-fly transparency changes in pixman renderer

When the alpha channel of a surface is changed and the surface
refreshed, pixman renderer will now apply a mask corresponding
to the alpha channel value.

This allows visual effects like shell fade in, shell fade out,
window switching, to work when using pixman renderer.

Signed-off-by: Manuel Bachmann <manuel.bachmann@open.eurogiciel.org>

diff --git a/src/pixman-renderer.c b/src/pixman-renderer.c
index b999343..eff7201 100644 (file)
--- a/src/pixman-renderer.c
+++ b/src/pixman-renderer.c
@@ -340,9 +340,16 @@ repaint_region(struct weston_view *ev, struct weston_output *output,
        if (ps->buffer_ref.buffer)
                wl_shm_buffer_begin_access(ps->buffer_ref.buffer->shm_buffer);
 
+       pixman_image_t *mask_image;
+       if (ev->alpha < 1.0) {
+               pixman_color_t mask = { 0x0000, 0x0000, 0x0000, 0xffff*ev->alpha };
+               mask_image = pixman_image_create_solid_fill(&mask);
+       } else
+               mask_image = NULL;
+
        pixman_image_composite32(pixman_op,
                                 ps->image, /* src */
-                                NULL /* mask */,
+                                mask_image, /* mask */
                                 po->shadow_image, /* dest */
                                 0, 0, /* src_x, src_y */
                                 0, 0, /* mask_x, mask_y */