image: replay the recording surface directly onto the target

백현기 reported a use-case where he was recording an entire web-page
onto the recording surface, in order to facilitate panning. In this
scenario, where there may be lots of similar surfaces within the
recording we generate thousands of unused snapshot-images bloating
memory usage and impairing performance.

Under the right conditions we can replay directly onto the destination
which not only bypasses the snapshots but also skips the following
resampling.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 15 insertions, 0 deletions

diff --git a/src/cairo-clip-private.h b/src/cairo-clip-private.h
index 2ad53efdc..7f44bdfc8 100644
--- a/src/cairo-clip-private.h
+++ b/src/cairo-clip-private.h
@@ -116,6 +116,18 @@ _cairo_clip_copy_intersect_rectangle (const cairo_clip_t       *clip,
 }
 
 cairo_private cairo_clip_t *
+_cairo_clip_intersect_clip (cairo_clip_t *clip,
+			    const cairo_clip_t *other);
+
+static inline cairo_clip_t *
+_cairo_clip_copy_intersect_clip (const cairo_clip_t *clip,
+				 const cairo_clip_t *other)
+{
+    return _cairo_clip_intersect_clip (_cairo_clip_copy (clip), other);
+}
+
+
+cairo_private cairo_clip_t *
 _cairo_clip_intersect_box (cairo_clip_t       *clip,
 			   const cairo_box_t *box);
 
@@ -151,6 +163,9 @@ cairo_private cairo_status_t
 _cairo_clip_to_boxes (cairo_clip_t *clip,
 		      cairo_boxes_t *boxes);
 
+cairo_private cairo_clip_t *
+_cairo_clip_from_boxes (const cairo_boxes_t *boxes);
+
 cairo_private cairo_region_t *
 _cairo_clip_get_region (const cairo_clip_t *clip);