More genericity: overload isPaintOpaque(SkPaint, SkBitmap)

src/core/SkPaintPriv.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkPaintPriv.h"
 
 #include "SkBitmap.h"
 #include "SkColorFilter.h"
 #include "SkPaint.h"
 #include "SkShader.h"
 
-bool isPaintOpaque(const SkPaint* paint,
-                   const SkBitmap* bmpReplacesShader) {
+bool isPaintOpaque(const SkPaint* paint, SkPaintBitmapOpacity contentType) {
     // TODO: SkXfermode should have a virtual isOpaque method, which would
     // make it possible to test modes that do not have a Coeff representation.
 
     if (!paint) {
-        return bmpReplacesShader ? bmpReplacesShader->isOpaque() : true;
+        return contentType != kUnknown_SkPaintBitmapOpacity;
     }
 
     SkXfermode::Coeff srcCoeff, dstCoeff;
     if (SkXfermode::AsCoeff(paint->getXfermode(), &srcCoeff, &dstCoeff)){
         if (SkXfermode::kDA_Coeff == srcCoeff || SkXfermode::kDC_Coeff == srcCoeff ||
             SkXfermode::kIDA_Coeff == srcCoeff || SkXfermode::kIDC_Coeff == srcCoeff) {
             return false;
         }
         switch (dstCoeff) {
         case SkXfermode::kZero_Coeff:
             return true;
         case SkXfermode::kISA_Coeff:
             if (paint->getAlpha() != 255) {
                 break;
             }
-            if (bmpReplacesShader) {
-                if (!bmpReplacesShader->isOpaque()) {
-                    break;
-                }
+            if (contentType == kUnknown_SkPaintBitmapOpacity) {
+                break;
             } else if (paint->getShader() && !paint->getShader()->isOpaque()) {
                 break;
             }
             if (paint->getColorFilter() &&
                 ((paint->getColorFilter()->getFlags() &
                 SkColorFilter::kAlphaUnchanged_Flag) == 0)) {
                 break;
             }
             return true;
         case SkXfermode::kSA_Coeff:
             if (paint->getAlpha() != 0) {
                 break;
             }
             if (paint->getColorFilter() &&
                 ((paint->getColorFilter()->getFlags() &
                 SkColorFilter::kAlphaUnchanged_Flag) == 0)) {
                 break;
             }
             return true;
         case SkXfermode::kSC_Coeff:
             if (paint->getColor() != 0) { // all components must be 0
                 break;
             }
-            if (bmpReplacesShader || paint->getShader()) {
+            if (contentType != kNoBitmap_SkPaintBitmapOpacity || paint->getShader()) {
                 break;
             }
             if (paint->getColorFilter() && (
                 (paint->getColorFilter()->getFlags() &
                 SkColorFilter::kAlphaUnchanged_Flag) == 0)) {
                 break;
             }
             return true;
         default:
             break;
         }
     }
     return false;
 }
+
+bool isPaintOpaque(const SkPaint* paint, const SkBitmap* bmpReplacesShader) {
+    SkPaintBitmapOpacity contentType;
+
+    if(!bmpReplacesShader)
+        contentType = kNoBitmap_SkPaintBitmapOpacity;
+    else if(bmpReplacesShader->isOpaque())
+        contentType = kOpaque_SkPaintBitmapOpacity;
+    else
+        contentType = kUnknown_SkPaintBitmapOpacity;
+
+    return isPaintOpaque(paint, contentType);
+}