[surface] Early return for (region IN white)

Fill a region using IN and a white source is a frequent reduction of a
complex clip (viz a path that covers the whole operation extents will be
reduced to a single rectangle), and we can simply discard the fill (as it
always has bounded semantics).

1 files changed, 7 insertions, 0 deletions

diff --git a/src/cairo-surface.c b/src/cairo-surface.c
index 6dab8e22..25ce0b92 100644
--- a/src/cairo-surface.c
+++ b/src/cairo-surface.c
@@ -1846,6 +1846,13 @@ _cairo_surface_fill_region (cairo_surface_t	   *surface,
     if (num_rects == 0)
 	return CAIRO_STATUS_SUCCESS;
 
+    /* catch a common reduction of _cairo_clip_combine_with_surface() */
+    if (op == CAIRO_OPERATOR_IN &&
+	_cairo_color_equal (color, CAIRO_COLOR_WHITE))
+    {
+	return CAIRO_STATUS_SUCCESS;
+    }
+
     if (num_rects > ARRAY_LENGTH (stack_rects)) {
 	rects = _cairo_malloc_ab (num_rects,
 				  sizeof (cairo_rectangle_int_t));