src/third_party/skia/src/core/SkPaintPriv.cpp

   1 /*
   2  * Copyright 2013 Google Inc.
   3  *
   4  * Use of this source code is governed by a BSD-style license that can be
   5  * found in the LICENSE file.
   6  */
   7
   8 #include "SkPaintPriv.h"
   9
  10 #include "SkBitmap.h"
  11 #include "SkColorFilter.h"
  12 #include "SkPaint.h"
  13 #include "SkShader.h"
  14
  15 bool isPaintOpaque(const SkPaint* paint, SkPaintBitmapOpacity contentType) {
  16     // TODO: SkXfermode should have a virtual isOpaque method, which would
  17     // make it possible to test modes that do not have a Coeff representation.
  18
  19     if (!paint) {
  20         return contentType != kUnknown_SkPaintBitmapOpacity;
  21     }
  22
  23     SkXfermode::Coeff srcCoeff, dstCoeff;
  24     if (SkXfermode::AsCoeff(paint->getXfermode(), &srcCoeff, &dstCoeff)){
  25         if (SkXfermode::kDA_Coeff == srcCoeff || SkXfermode::kDC_Coeff == srcCoeff ||
  26             SkXfermode::kIDA_Coeff == srcCoeff || SkXfermode::kIDC_Coeff == srcCoeff) {
  27             return false;
  28         }
  29         switch (dstCoeff) {
  30         case SkXfermode::kZero_Coeff:
  31             return true;
  32         case SkXfermode::kISA_Coeff:
  33             if (paint->getAlpha() != 255) {
  34                 break;
  35             }
  36             if (contentType == kUnknown_SkPaintBitmapOpacity) {
  37                 break;
  38             } else if (paint->getShader() && !paint->getShader()->isOpaque()) {
  39                 break;
  40             }
  41             if (paint->getColorFilter() &&
  42                 ((paint->getColorFilter()->getFlags() &
  43                 SkColorFilter::kAlphaUnchanged_Flag) == 0)) {
  44                 break;
  45             }
  46             return true;
  47         case SkXfermode::kSA_Coeff:
  48             if (paint->getAlpha() != 0) {
  49                 break;
  50             }
  51             if (paint->getColorFilter() &&
  52                 ((paint->getColorFilter()->getFlags() &
  53                 SkColorFilter::kAlphaUnchanged_Flag) == 0)) {
  54                 break;
  55             }
  56             return true;
  57         case SkXfermode::kSC_Coeff:
  58             if (paint->getColor() != 0) { // all components must be 0
  59                 break;
  60             }
  61             if (contentType != kNoBitmap_SkPaintBitmapOpacity || paint->getShader()) {
  62                 break;
  63             }
  64             if (paint->getColorFilter() && (
  65                 (paint->getColorFilter()->getFlags() &
  66                 SkColorFilter::kAlphaUnchanged_Flag) == 0)) {
  67                 break;
  68             }
  69             return true;
  70         default:
  71             break;
  72         }
  73     }
  74     return false;
  75 }
  76
  77 bool isPaintOpaque(const SkPaint* paint, const SkBitmap* bmpReplacesShader) {
  78     SkPaintBitmapOpacity contentType;
  79
  80     if(!bmpReplacesShader)
  81         contentType = kNoBitmap_SkPaintBitmapOpacity;
  82     else if(bmpReplacesShader->isOpaque())
  83         contentType = kOpaque_SkPaintBitmapOpacity;
  84     else
  85         contentType = kUnknown_SkPaintBitmapOpacity;
  86
  87     return isPaintOpaque(paint, contentType);
  88 }