Create fragment processor for performing input color blend with child processor

src/core/SkComposeShader.cpp

 
 /*
  * 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.
  */
 
 
 #include "SkComposeShader.h"
@@ skipping 189 matching lines @@
 #include "effects/GrXfermodeFragmentProcessor.h"
 
 /////////////////////////////////////////////////////////////////////
 
 const GrFragmentProcessor* SkComposeShader::asFragmentProcessor(GrContext* context,
                                                             const SkMatrix& viewM,
                                                             const SkMatrix* localMatrix,
                                                             SkFilterQuality fq,
                                                             GrProcessorDataManager* procDataManager
                                                             ) const {
-    // Fragment processor will only support coefficient modes. This is because
-    // GrGLBlend::AppendPorterDuffBlend(), which emits the blend code in the shader,
-    // only supports those modes.
+    // Fragment processor will only support SkXfermode::Mode modes currently.
     SkXfermode::Mode mode;
-    if (!(SkXfermode::AsMode(fMode, &mode) && SkXfermode::kLastCoeffMode >= mode)) {
+    if (!(SkXfermode::AsMode(fMode, &mode))) {
         return nullptr;
     }
 
     switch (mode) {
         case SkXfermode::kClear_Mode:
-            return GrConstColorProcessor::Create(GrColor_TRANS_BLACK,
+            return GrConstColorProcessor::Create(GrColor_TRANSPARENT_BLACK,
                                                  GrConstColorProcessor::kIgnore_InputMode);
             break;
         case SkXfermode::kSrc_Mode:
             return fShaderB->asFragmentProcessor(context, viewM, localMatrix, fq, procDataManager);
             break;
         case SkXfermode::kDst_Mode:
             return fShaderA->asFragmentProcessor(context, viewM, localMatrix, fq, procDataManager);
             break;
         default:
             SkAutoTUnref<const GrFragmentProcessor> fpA(fShaderA->asFragmentProcessor(context,
@@ skipping 22 matching lines @@
     if (fMode) {
         str->append(" Xfermode: ");
         fMode->toString(str);
     }
 
     this->INHERITED::toString(str);
 
     str->append(")");
 }
 #endif