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,
  16                    const SkBitmap* bmpReplacesShader) {
  17     // TODO: SkXfermode should have a virtual isOpaque method, which would
  18     // make it possible to test modes that do not have a Coeff representation.
  19
  20     if (!paint) {
  21         return bmpReplacesShader ? bmpReplacesShader->isOpaque() : true;
  22     }
  23
  24     SkXfermode::Coeff srcCoeff, dstCoeff;
  25     if (SkXfermode::AsCoeff(paint->getXfermode(), &srcCoeff, &dstCoeff)){
  26         if (SkXfermode::kDA_Coeff == srcCoeff || SkXfermode::kDC_Coeff == srcCoeff ||
  27             SkXfermode::kIDA_Coeff == srcCoeff || SkXfermode::kIDC_Coeff == srcCoeff) {
  28             return false;
  29         }
  30         switch (dstCoeff) {
  31         case SkXfermode::kZero_Coeff:
  32             return true;
  33         case SkXfermode::kISA_Coeff:
  34             if (paint->getAlpha() != 255) {
  35                 break;
  36             }
  37             if (bmpReplacesShader) {
  38                 if (!bmpReplacesShader->isOpaque()) {
  39                     break;
  40                 }
  41             } else if (paint->getShader() && !paint->getShader()->isOpaque()) {
  42                 break;
  43             }
  44             if (paint->getColorFilter() &&
  45                 ((paint->getColorFilter()->getFlags() &
  46                 SkColorFilter::kAlphaUnchanged_Flag) == 0)) {
  47                 break;
  48             }
  49             return true;
  50         case SkXfermode::kSA_Coeff:
  51             if (paint->getAlpha() != 0) {
  52                 break;
  53             }
  54             if (paint->getColorFilter() &&
  55                 ((paint->getColorFilter()->getFlags() &
  56                 SkColorFilter::kAlphaUnchanged_Flag) == 0)) {
  57                 break;
  58             }
  59             return true;
  60         case SkXfermode::kSC_Coeff:
  61             if (paint->getColor() != 0) { // all components must be 0
  62                 break;
  63             }
  64             if (bmpReplacesShader || paint->getShader()) {
  65                 break;
  66             }
  67             if (paint->getColorFilter() && (
  68                 (paint->getColorFilter()->getFlags() &
  69                 SkColorFilter::kAlphaUnchanged_Flag) == 0)) {
  70                 break;
  71             }
  72             return true;
  73         default:
  74             break;
  75         }
  76     }
  77     return false;
  78 }
  79
  80 bool NeedsDeepCopy(const SkPaint& paint) {
  81     /*
  82      *  The types below are not yet immutable/reentrant-safe, and so we return
  83      *  true if instances of them are present in the paint.
  84      *
  85      *  Eventually we hope this list will be empty, and we can always return
  86      *  false.
  87      */
  88     return paint.getImageFilter();
  89 }