Adding optimization to avoid image copy in SkSurface copy on write when content is discardable
This patch also adds code to SkDeferredCanvas to trigger the optimization.
TEST=DeferredSurfaceCopy bench, Surface unit test
R=reed@google.com
Author: junov@chromium.org
Review URL: https://chromiumcodereview.appspot.com/14063015
git-svn-id: http://skia.googlecode.com/svn/trunk@8797 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/include/core/SkSurface.h b/include/core/SkSurface.h
index d4d5c52..cf139b1 100644
--- a/include/core/SkSurface.h
+++ b/include/core/SkSurface.h
@@ -79,10 +79,26 @@
uint32_t generationID();
/**
- * Call this if the contents have changed. This will (lazily) force a new
+ * Modes that can be passed to notifyContentWillChange
+ */
+ enum ContentChangeMode {
+ /**
+ * Use this mode if it is known that the upcoming content changes will
+ * clear or overwrite prior contents, thus making them discardable.
+ */
+ kDiscard_ContentChangeMode,
+ /**
+ * Use this mode if prior surface contents need to be preserved or
+ * if in doubt.
+ */
+ kRetain_ContentChangeMode,
+ };
+
+ /**
+ * Call this if the contents are about to change. This will (lazily) force a new
* value to be returned from generationID() when it is called next.
*/
- void notifyContentChanged();
+ void notifyContentWillChange(ContentChangeMode mode);
/**
* Return a canvas that will draw into this surface. This will always