[image] Discard redundant clears

On slow machines the call to pixman_fill_sse2() on similar surfaces that
we know are already zeroed takes a significant amount of time [12.77% of
the profile for a firefox trace, cf to just 3% of the profile is spent
inside memset].

Rather than solve why the pixman_fill_sse2() is so slow, simply skip the
redundant clears.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/cairoint.h b/src/cairoint.h
index 3cd0cb37..6010e20f 100644
--- a/src/cairoint.h
+++ b/src/cairoint.h
@@ -857,6 +857,7 @@ struct _cairo_image_surface {
     pixman_image_t *pixman_image;
     cairo_region_t *clip_region;
 
+    unsigned is_clear : 1;
     unsigned owns_data : 1;
     unsigned transparency : 2;
 };