1 /*
2  * Copyright 2015 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 "SkXfermodeInterpretation.h"
9 #include "SkPaint.h"
10 
just_solid_color(const SkPaint & p)11 static bool just_solid_color(const SkPaint& p) {
12     return SK_AlphaOPAQUE == p.getAlpha() && !p.getColorFilter() && !p.getShader();
13 }
14 
SkInterpretXfermode(const SkPaint & paint,bool dstIsOpaque)15 SkXfermodeInterpretation SkInterpretXfermode(const SkPaint& paint, bool dstIsOpaque) {
16     switch (paint.getBlendMode()) {
17         case SkBlendMode::kSrcOver:
18             return kSrcOver_SkXfermodeInterpretation;
19         case SkBlendMode::kSrc:
20             if (just_solid_color(paint)) {
21                 return kSrcOver_SkXfermodeInterpretation;
22             }
23             return kNormal_SkXfermodeInterpretation;
24         case SkBlendMode::kDst:
25             return kSkipDrawing_SkXfermodeInterpretation;
26         case SkBlendMode::kDstOver:
27             if (dstIsOpaque) {
28                 return kSkipDrawing_SkXfermodeInterpretation;
29             }
30             return kNormal_SkXfermodeInterpretation;
31         case SkBlendMode::kSrcIn:
32             if (dstIsOpaque && just_solid_color(paint)) {
33                 return kSrcOver_SkXfermodeInterpretation;
34             }
35             return kNormal_SkXfermodeInterpretation;
36         case SkBlendMode::kDstIn:
37             if (just_solid_color(paint)) {
38                 return kSkipDrawing_SkXfermodeInterpretation;
39             }
40             return kNormal_SkXfermodeInterpretation;
41         default:
42             return kNormal_SkXfermodeInterpretation;
43     }
44 }
45