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

src/core/SkMaskFilter.cpp

 
 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "SkMaskFilter.h"
 #include "SkBlitter.h"
 #include "SkDraw.h"
+#include "SkMaskCache.h"
 #include "SkRasterClip.h"
 #include "SkRRect.h"
 #include "SkTypes.h"
 
 #if SK_SUPPORT_GPU
 #include "GrTexture.h"
 #include "SkGr.h"
 #include "SkGrPixelRef.h"
 #endif
 
@@ skipping 233 matching lines @@
 
     SkMask  srcM, dstM;
 
     if (!SkDraw::DrawToMask(devPath, &clip.getBounds(), this, &matrix, &srcM,
                             SkMask::kComputeBoundsAndRenderImage_CreateMode,
                             style)) {
         return false;
     }
     SkAutoMaskFreeImage autoSrc(srcM.fImage);
 
-    if (!this->filterMask(&dstM, srcM, matrix, NULL)) {
-        return false;
+    BlurRec rec;
+    if (!this->asABlur(&rec)
+        || !rectCount

[reed1, 2014/12/22 21:38:16]

This 4-part predicate may be correct, but it is pretty complex for me to read.
Can it be restructured to make it clearer?

[qiankun, 2014/12/23 10:54:32]

What about the latest implementation?

+        || (this->asABlur(&rec) && !SkMaskCache::FindCachedRects(&dstM, matrix.mapRadius(rec.fSigma), rec.fStyle,
+                                                                 rec.fQuality, rects, rectCount))) {
+        if (!this->filterMask(&dstM, srcM, matrix, NULL)) {
+            return false;
+        }
+        if (this->asABlur(&rec) && rectCount) {
+            SkMaskCache::AddCachedRects(dstM, matrix.mapRadius(rec.fSigma), rec.fStyle, rec.fQuality, rects, rectCount);
+        }
+    } 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 size of the cached mask.
+        if (dstM.fBounds.width() != tmpDst.fBounds.width() || dstM.fBounds.height() != tmpDst.fBounds.height()) {
+            this->filterMask(&dstM, srcM, matrix, NULL);
+        } else {
+            dstM.fBounds = tmpDst.fBounds;
+        }
     }
+
     SkAutoMaskFreeImage autoDst(dstM.fImage);
 
     // if we get here, we need to (possibly) resolve the clip and blitter
     SkAAClipBlitterWrapper wrapper(clip, blitter);
     blitter = wrapper.getBlitter();
 
     SkRegion::Cliperator clipper(wrapper.getRgn(), dstM.fBounds);
 
     if (!clipper.done()) {
         const SkIRect& cr = clipper.rect();
@@ skipping 62 matching lines @@
     srcM.fRowBytes = 0;
     srcM.fFormat = SkMask::kA8_Format;
 
     SkIPoint margin;    // ignored
     if (this->filterMask(&dstM, srcM, SkMatrix::I(), &margin)) {
         dst->set(dstM.fBounds);
     } else {
         dst->set(srcM.fBounds);
     }
 }