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
11static bool just_solid_color(const SkPaint& p) {
12    return SK_AlphaOPAQUE == p.getAlpha()
13        && !p.getColorFilter() && !p.getShader();
14}
15
16SkXfermodeInterpretation SkInterpretXfermode(const SkPaint& paint,
17                                             bool dstIsOpaque) {
18    const SkXfermode* xfer = paint.getXfermode();
19    SkXfermode::Mode mode;
20    if (!SkXfermode::AsMode(xfer, &mode)) {
21        return kNormal_SkXfermodeInterpretation;
22    }
23    switch (mode) {
24        case SkXfermode::kSrcOver_Mode:
25            return kSrcOver_SkXfermodeInterpretation;
26        case SkXfermode::kSrc_Mode:
27            if (just_solid_color(paint)) {
28                return kSrcOver_SkXfermodeInterpretation;
29            }
30            return kNormal_SkXfermodeInterpretation;
31        case SkXfermode::kDst_Mode:
32            return kSkipDrawing_SkXfermodeInterpretation;
33        case SkXfermode::kDstOver_Mode:
34            if (dstIsOpaque) {
35                return kSkipDrawing_SkXfermodeInterpretation;
36            }
37            return kNormal_SkXfermodeInterpretation;
38        case SkXfermode::kSrcIn_Mode:
39            if (dstIsOpaque && just_solid_color(paint)) {
40                return kSrcOver_SkXfermodeInterpretation;
41            }
42            return kNormal_SkXfermodeInterpretation;
43        case SkXfermode::kDstIn_Mode:
44            if (just_solid_color(paint)) {
45                return kSkipDrawing_SkXfermodeInterpretation;
46            }
47            return kNormal_SkXfermodeInterpretation;
48        default:
49            return kNormal_SkXfermodeInterpretation;
50    }
51}
52