Improved distance field sampling

src/gpu/effects/GrDistanceFieldTextureEffect.h

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrDistanceFieldTextureEffect_DEFINED
 #define GrDistanceFieldTextureEffect_DEFINED
 
 #include "GrEffect.h"
 #include "GrVertexEffect.h"
 
 class GrGLDistanceFieldTextureEffect;
 
 /**
  * The output color of this effect is a modulation of the input color and a sample from a
  * distance field texture (using a smoothed step function near 0.5).
  * It allows explicit specification of the filtering and wrap modes (GrTextureParams). The input
  * coords are a custom attribute.
  */
 class GrDistanceFieldTextureEffect : public GrVertexEffect {
 public:
-    static GrEffectRef* Create(GrTexture* tex, const GrTextureParams& p) {
-        AutoEffectUnref effect(SkNEW_ARGS(GrDistanceFieldTextureEffect, (tex, p)));
+    static GrEffectRef* Create(GrTexture* tex, const GrTextureParams& p, const SkISize& s) {
+        AutoEffectUnref effect(SkNEW_ARGS(GrDistanceFieldTextureEffect, (tex, p, s)));
         return CreateEffectRef(effect);
     }
 
     virtual ~GrDistanceFieldTextureEffect() {}
 
-    static const char* Name() { return "Texture"; }
+    static const char* Name() { return "DistanceFieldTexture"; }
 
     virtual void getConstantColorComponents(GrColor* color, uint32_t* validFlags) const SK_OVERRIDE;
+    const SkSize& getSize() const { return fSize; }
 
     typedef GrGLDistanceFieldTextureEffect GLEffect;
 
     virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE;
 
 private:
-    GrDistanceFieldTextureEffect(GrTexture* texture, const GrTextureParams& params);
+    GrDistanceFieldTextureEffect(GrTexture* texture, const GrTextureParams& params, 
+                                 const SkISize& textureSize);
 
     virtual bool onIsEqual(const GrEffect& other) const SK_OVERRIDE;
 
     GrTextureAccess fTextureAccess;
+    SkSize          fSize;
 
     GR_DECLARE_EFFECT_TEST;
 
     typedef GrVertexEffect INHERITED;
 };
 
 #endif