Implement a computeFastBounds() traversal for SkImageFilter. This allows for correct culling of pri…

src/effects/SkMorphologyImageFilter.cpp

 /*
  * Copyright 2012 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 "SkMorphologyImageFilter.h"
 #include "SkBitmap.h"
 #include "SkColorPriv.h"
@@ skipping 221 matching lines @@
     if (!dilateXProc) {
         dilateXProc = dilate<kX>;
     }
     Proc dilateYProc = SkMorphologyGetPlatformProc(kDilateY_SkMorphologyProcType);
     if (!dilateYProc) {
         dilateYProc = dilate<kY>;
     }
     return this->filterImageGeneric(dilateXProc, dilateYProc, proxy, source, ctm, dst, offset);
 }
 
+void SkMorphologyImageFilter::computeFastBounds(const SkRect& src, SkRect* dst) const {
+    if (getInput(0)) {
+        getInput(0)->computeFastBounds(src, dst);
+    } else {
+        *dst = src;
+    }
+    dst->outset(SkIntToScalar(fRadius.width()), SkIntToScalar(fRadius.height()));
+}
+
 #if SK_SUPPORT_GPU
 
 ///////////////////////////////////////////////////////////////////////////////
 
 class GrGLMorphologyEffect;
 
 /**
  * Morphology effects. Depending upon the type of morphology, either the
  * component-wise min (Erode_Type) or max (Dilate_Type) of all pixels in the
  * kernel is selected as the new color. The new color is modulated by the input
@@ skipping 309 matching lines @@
                                          SkBitmap* result, SkIPoint* offset) {
     return this->filterImageGPUGeneric(true, proxy, src, ctm, result, offset);
 }
 
 bool SkErodeImageFilter::filterImageGPU(Proxy* proxy, const SkBitmap& src, const SkMatrix& ctm,
                                         SkBitmap* result, SkIPoint* offset) {
     return this->filterImageGPUGeneric(false, proxy, src, ctm, result, offset);
 }
 
 #endif