Allow clients to specify an external SkImageFilter cache.

include/core/SkImageFilter.h

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkImageFilter_DEFINED
 #define SkImageFilter_DEFINED
 
@@ skipping 38 matching lines @@
     };
 
     class Cache : public SkRefCnt {
     public:
         // By default, we cache only image filters with 2 or more children.
         static Cache* Create(int minChildren = 2);
         virtual ~Cache() {}
         virtual bool get(const SkImageFilter* key, SkBitmap* result, SkIPoint* offset) = 0;
         virtual void set(const SkImageFilter* key,
                          const SkBitmap& result, const SkIPoint& offset) = 0;
+        virtual void remove(const SkImageFilter* key) = 0;
     };
 
     class Context {
     public:
         Context(const SkMatrix& ctm, const SkIRect& clipBounds, Cache* cache) :
             fCTM(ctm), fClipBounds(clipBounds), fCache(cache) {
         }
         const SkMatrix& ctm() const { return fCTM; }
         const SkIRect& clipBounds() const { return fClipBounds; }
         Cache* cache() const { return fCache; }
@@ skipping 107 matching lines @@
     static void WrapTexture(GrTexture* texture, int width, int height, SkBitmap* result);
 
     /**
      * Recursively evaluate this filter on the GPU. If the filter has no GPU
      * implementation, it will be processed in software and uploaded to the GPU.
      */
     bool getInputResultGPU(SkImageFilter::Proxy* proxy, const SkBitmap& src, const Context&,
                            SkBitmap* result, SkIPoint* offset) const;
 #endif
 
+    /**
+     *  Set an external cache to be used for all image filter processing. This
+     *  will replace the default intra-frame cache.
+     */
+    static void SetExternalCache(Cache* cache);
+
+    /**
+     *  Returns the currently-set external cache, or NULL if none is set.
+     */
+    static Cache* GetExternalCache();
+
     SK_DEFINE_FLATTENABLE_TYPE(SkImageFilter)
 
 protected:
     SkImageFilter(int inputCount, SkImageFilter** inputs, const CropRect* cropRect = NULL);
 
     // Convenience constructor for 1-input filters.
     explicit SkImageFilter(SkImageFilter* input, const CropRect* cropRect = NULL);
 
     // Convenience constructor for 2-input filters.
     SkImageFilter(SkImageFilter* input1, SkImageFilter* input2, const CropRect* cropRect = NULL);
@@ skipping 71 matching lines @@
      *  in the texture.  "matrix" is a transformation to apply to filter
      *  parameters before they are used in the effect. Note that this function
      *  will be called with (NULL, NULL, SkMatrix::I()) to query for support,
      *  so returning "true" indicates support for all possible matrices.
      */
     virtual bool asNewEffect(GrEffectRef** effect,
                              GrTexture*,
                              const SkMatrix& matrix,
                              const SkIRect& bounds) const;
 
-
 private:
     typedef SkFlattenable INHERITED;
     int fInputCount;
     SkImageFilter** fInputs;
     CropRect fCropRect;
 };
 
 #endif