Allow clients to specify an external SkImageFilter cache.

This change allows external callers to substitute their own
SkImageFilter cache for the default intra-frame cache in Skia. This
allows the caller to perform inter-frame caching for example, by the
maintaining a persistent cache between frames and doing custom
invalidation.

R=reed@google.com

Review URL: https://codereview.chromium.org/225903010

git-svn-id: http://skia.googlecode.com/svn/trunk@14181 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 12 insertions, 4 deletions

diff --git a/src/core/SkCanvas.cpp b/src/core/SkCanvas.cpp
index a3e2969514..569e9e59ba 100644
--- a/src/core/SkCanvas.cpp
+++ b/src/core/SkCanvas.cpp
@@ -1258,8 +1258,12 @@ void SkCanvas::internalDrawDevice(SkBaseDevice* srcDev, int x, int y,
             SkMatrix matrix = *iter.fMatrix;
             matrix.postTranslate(SkIntToScalar(-pos.x()), SkIntToScalar(-pos.y()));
             SkIRect clipBounds = SkIRect::MakeWH(srcDev->width(), srcDev->height());
-            SkImageFilter::Cache* cache = SkImageFilter::Cache::Create();
-            SkAutoUnref aur(cache);
+            SkImageFilter::Cache* cache = SkImageFilter::GetExternalCache();
+            SkAutoUnref aur(NULL);
+            if (!cache) {
+                cache = SkImageFilter::Cache::Create();
+                aur.reset(cache);
+            }
             SkImageFilter::Context ctx(matrix, clipBounds, cache);
             if (filter->filterImage(&proxy, src, ctx, &dst, &offset)) {
                 SkPaint tmpUnfiltered(*paint);
@@ -1300,8 +1304,12 @@ void SkCanvas::drawSprite(const SkBitmap& bitmap, int x, int y,
             SkMatrix matrix = *iter.fMatrix;
             matrix.postTranslate(SkIntToScalar(-pos.x()), SkIntToScalar(-pos.y()));
             SkIRect clipBounds = SkIRect::MakeWH(bitmap.width(), bitmap.height());
-            SkImageFilter::Cache* cache = SkImageFilter::Cache::Create();
-            SkAutoUnref aur(cache);
+            SkImageFilter::Cache* cache = SkImageFilter::GetExternalCache();
+            SkAutoUnref aur(NULL);
+            if (!cache) {
+                cache = SkImageFilter::Cache::Create();
+                aur.reset(cache);
+            }
             SkImageFilter::Context ctx(matrix, clipBounds, cache);
             if (filter->filterImage(&proxy, bitmap, ctx, &dst, &offset)) {
                 SkPaint tmpUnfiltered(*paint);