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 "SkBitmap.h" 9 #include "SkColorFilter.h" 10 #include "SkPaintPriv.h" 11 #include "SkImage.h" 12 #include "SkPaint.h" 13 #include "SkShader.h" 14 15 static bool changes_alpha(const SkPaint& paint) { 16 SkColorFilter* cf = paint.getColorFilter(); 17 return cf && !(cf->getFlags() & SkColorFilter::kAlphaUnchanged_Flag); 18 } 19 20 bool SkPaintPriv::Overwrites(const SkPaint* paint, ShaderOverrideOpacity overrideOpacity) { 21 if (!paint) { 22 // No paint means we default to SRC_OVER, so we overwrite iff our shader-override 23 // is opaque, or we don't have one. 24 return overrideOpacity != kNotOpaque_ShaderOverrideOpacity; 25 } 26 27 SkXfermode::SrcColorOpacity opacityType = SkXfermode::kUnknown_SrcColorOpacity; 28 29 if (!changes_alpha(*paint)) { 30 const unsigned paintAlpha = paint->getAlpha(); 31 if (0xff == paintAlpha && overrideOpacity != kNotOpaque_ShaderOverrideOpacity && 32 (!paint->getShader() || paint->getShader()->isOpaque())) 33 { 34 opacityType = SkXfermode::kOpaque_SrcColorOpacity; 35 } else if (0 == paintAlpha) { 36 if (overrideOpacity == kNone_ShaderOverrideOpacity && !paint->getShader()) { 37 opacityType = SkXfermode::kTransparentBlack_SrcColorOpacity; 38 } else { 39 opacityType = SkXfermode::kTransparentAlpha_SrcColorOpacity; 40 } 41 } 42 } 43 44 return SkXfermode::IsOpaque(paint->getXfermode(), opacityType); 45 } 46 47 bool SkPaintPriv::Overwrites(const SkBitmap& bitmap, const SkPaint* paint) { 48 return Overwrites(paint, bitmap.isOpaque() ? kOpaque_ShaderOverrideOpacity 49 : kNotOpaque_ShaderOverrideOpacity); 50 } 51 52 bool SkPaintPriv::Overwrites(const SkImage* image, const SkPaint* paint) { 53 return Overwrites(paint, image->isOpaque() ? kOpaque_ShaderOverrideOpacity 54 : kNotOpaque_ShaderOverrideOpacity); 55 } 56
