Implement crop rect for SkImageFilter

src/gpu/effects/GrConvolutionEffect.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrConvolutionEffect_DEFINED
 #define GrConvolutionEffect_DEFINED
 
 #include "Gr1DKernelEffect.h"
 
 class GrGLConvolutionEffect;
 
 /**
  * A convolution effect. The kernel is specified as an array of 2 * half-width
  * + 1 weights. Each texel is multiplied by it's weight and summed to determine
  * the output color. The output color is modulated by the input color.
  */
 class GrConvolutionEffect : public Gr1DKernelEffect {
 
 public:
 
     /// Convolve with an arbitrary user-specified kernel
-    static GrEffectRef* Create(GrTexture* tex, Direction dir, int halfWidth, const float* kernel) {
+    static GrEffectRef* Create(GrTexture* tex, Direction dir, int halfWidth, const float* kernel, float cropRect[4]) {
         AutoEffectUnref effect(SkNEW_ARGS(GrConvolutionEffect, (tex,
                                                                 dir,
                                                                 halfWidth,
-                                                                kernel)));
+                                                                kernel,
+                                                                cropRect)));
         return CreateEffectRef(effect);
     }
 
     /// Convolve with a Gaussian kernel
     static GrEffectRef* CreateGaussian(GrTexture* tex,
                                        Direction dir,
                                        int halfWidth,
-                                       float gaussianSigma) {
+                                       float gaussianSigma,
+                                       float cropRect[4]) {
         AutoEffectUnref effect(SkNEW_ARGS(GrConvolutionEffect, (tex,
                                                                 dir,
                                                                 halfWidth,
-                                                                gaussianSigma)));
+                                                                gaussianSigma,
+                                                                cropRect)));
         return CreateEffectRef(effect);
     }
 
     virtual ~GrConvolutionEffect();
 
     const float* kernel() const { return fKernel; }
 
+    const float* cropRect() const { return fCropRect; }
+
     static const char* Name() { return "Convolution"; }
 
     typedef GrGLConvolutionEffect GLEffect;
 
     virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE;
 
     virtual void getConstantColorComponents(GrColor*, uint32_t* validFlags) const {
         // If the texture was opaque we could know that the output color if we knew the sum of the
         // kernel values.
         *validFlags = 0;
     }
 
     enum {
         // This was decided based on the min allowed value for the max texture
         // samples per fragment program run in DX9SM2 (32). A sigma param of 4.0
         // on a blur filter gives a kernel width of 25 while a sigma of 5.0
         // would exceed a 32 wide kernel.
         kMaxKernelRadius = 12,
         // With a C++11 we could have a constexpr version of WidthFromRadius()
         // and not have to duplicate this calculation.
         kMaxKernelWidth = 2 * kMaxKernelRadius + 1,
     };
 
 protected:
 
     float fKernel[kMaxKernelWidth];
+    float fCropRect[4];
 
 private:
     GrConvolutionEffect(GrTexture*, Direction,
-                        int halfWidth, const float* kernel);
+                        int halfWidth, const float* kernel, float cropRect[4]);
 
     /// Convolve with a Gaussian kernel
     GrConvolutionEffect(GrTexture*, Direction,
                         int halfWidth,
-                        float gaussianSigma);
+                        float gaussianSigma,
+                        float cropRect[4]);
 
     virtual bool onIsEqual(const GrEffect&) const SK_OVERRIDE;
 
     GR_DECLARE_EFFECT_TEST;
 
     typedef Gr1DKernelEffect INHERITED;
 };
 
 #endif