Revert of Change SkShader;asFragmentProcessor signature to no longer take skpaint\grcolor*

include/core/SkShader.h

 /*
  * 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.
  */
 
 #ifndef SkShader_DEFINED
 #define SkShader_DEFINED
 
@@ skipping 316 matching lines @@
     struct ComposeRec {
         const SkShader*     fShaderA;
         const SkShader*     fShaderB;
         const SkXfermode*   fMode;
     };
 
     virtual bool asACompose(ComposeRec*) const { return false; }
 
 
     /**
-     *  Returns a GrFragmentProcessor that implements the shader for the GPU backend. NULL is
-     *  returned if there is no GPU implementation.
+     *  Returns true if the shader subclass succeeds in creating an effect or if none is required.
+     *  False is returned if it fails or if there is not an implementation of this method in the
+     *  shader subclass.
      *
-     *  The GPU device does not call SkShader::createContext(), instead we pass the view matrix,
-     *  local matrix, and filter quality directly.
+     *  On success an implementation of this method must inspect the SkPaint and set paintColor to
+     *  the color the effect expects as its input color. If the SkShader wishes to emit a solid
+     *  color then it should set paintColor to that color and not create an effect. Note that
+     *  GrColor is always premul. The common patterns are to convert paint's SkColor to GrColor or
+     *  to extract paint's alpha and replicate it to all channels in paintColor. Upon failure
+     *  paintColor should not be modified. It is not recommended to specialize the effect to
+     *  the paint's color as then many GPU shaders may be generated.
      *
-     *  The GrContext may be used by the to create textures that are required by the returned
-     *  processor.
+     *  The GrContext may be used by the effect to create textures. The GPU device does not
+     *  call createContext. Instead we pass the SkPaint here in case the shader needs paint info.
+     *
+     *  A view matrix is always required to create the correct GrFragmentProcessor.  Some shaders
+     *  may also use the optional localMatrix to define a matrix relevant only for sampling.
      */
-    virtual const GrFragmentProcessor* asFragmentProcessor(GrContext*,
-                                                           const SkMatrix& viewMatric,
-                                                           const SkMatrix* localMatrix,
-                                                           SkFilterQuality,
-                                                           GrProcessorDataManager*) const;
+    virtual bool asFragmentProcessor(GrContext*, const SkPaint&, const SkMatrix& viewM,
+                                     const SkMatrix* localMatrix, GrColor*,
+                                     GrProcessorDataManager*, GrFragmentProcessor**) const;
 
     /**
      *  If the shader can represent its "average" luminance in a single color, return true and
      *  if color is not NULL, return that color. If it cannot, return false and ignore the color
      *  parameter.
      *
      *  Note: if this returns true, the returned color will always be opaque, as only the RGB
      *  components are used to compute luminance.
      */
     bool asLuminanceColor(SkColor*) const;
@@ skipping 96 matching lines @@
     // constructors.
     SkMatrix fLocalMatrix;
 
     // So the SkLocalMatrixShader can whack fLocalMatrix in its SkReadBuffer constructor.
     friend class SkLocalMatrixShader;
 
     typedef SkFlattenable INHERITED;
 };
 
 #endif