Cache blur mask for rects which can not break into nine-patch

src/core/SkMaskFilter.cpp

Index: src/core/SkMaskFilter.cpp
diff --git a/src/core/SkMaskFilter.cpp b/src/core/SkMaskFilter.cpp
index c9783e76d6113e7bd9abb9a800341a1d83591c42..be4ec9e9e6f3d442231a18fb15075d3c537a5005 100644
--- a/src/core/SkMaskFilter.cpp
+++ b/src/core/SkMaskFilter.cpp
@@ -10,6 +10,7 @@
 #include "SkMaskFilter.h"
 #include "SkBlitter.h"
 #include "SkDraw.h"
+#include "SkMaskCache.h"
 #include "SkRasterClip.h"
 #include "SkRRect.h"
 #include "SkTypes.h"
@@ -263,9 +264,42 @@ bool SkMaskFilter::filterPath(const SkPath& devPath, const SkMatrix& matrix,
     }
     SkAutoMaskFreeImage autoSrc(srcM.fImage);
 
-    if (!this->filterMask(&dstM, srcM, matrix, NULL)) {
-        return false;
+    BlurRec rec;
+    if (this->asABlur(&rec) && rectCount) {
+        SkScalar scaledSigma = matrix.mapRadius(rec.fSigma);
+        if (!SkMaskCache::FindAndCopy(scaledSigma, rec.fStyle, rec.fQuality,

[reed1, 2015/01/08 15:51:21]

I think it will be easier to read if we change this from 

if (!...

to

if (...

so we can see the code that handles a cache-hit right below the FindAndCopy

[qiankun, 2015/01/12 04:36:26]

Done.

+                                      rects, rectCount, &dstM)) {
+            if (!this->filterMask(&dstM, srcM, matrix, NULL)) {
+                return false;
+            }
+            SkMaskCache::AddAndCopy(scaledSigma, rec.fStyle, rec.fQuality, rects, rectCount, dstM);
+        } else {
+            // Compute the correct bounds of dst mask if dst mask is got from cache.
+            SkMask tmpSrc, tmpDst;
+            tmpSrc = srcM;
+            tmpSrc.fImage = NULL;
+            if (!this->filterMask(&tmpDst, tmpSrc, matrix, NULL)) {
+                return false;
+            }
+
+            // Fallback to original calculation if size of bounds is different with

[reed1, 2015/01/08 15:51:21]

I'm afraid I still don't understand the scenario this is catching. We have a
cache "hit", but we can't use it, so we have to delete the copied answer?

[qiankun, 2015/01/12 04:36:26]

It was used to handle clipping bounds. Now, the new CL don't search the cache
for clipped dst bounds.

+            // size of the cached mask.
+            if (dstM.fBounds.width() != tmpDst.fBounds.width() ||
+                dstM.fBounds.height() != tmpDst.fBounds.height()) {
+                SkMask::FreeImage(dstM.fImage);
+                if (!this->filterMask(&dstM, srcM, matrix, NULL)) {
+                    return false;
+                }
+            } else {
+                dstM.fBounds = tmpDst.fBounds;
+            }
+        }
+    } else {
+        if (!this->filterMask(&dstM, srcM, matrix, NULL)) {
+            return false;
+        }
     }
+
     SkAutoMaskFreeImage autoDst(dstM.fImage);
 
     // if we get here, we need to (possibly) resolve the clip and blitter