1
2/*
3 * Copyright 2006 The Android Open Source Project
4 *
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
7 */
8
9
10#include "SkTransparentShader.h"
11#include "SkColorPriv.h"
12#include "SkString.h"
13
14SkShader::Context* SkTransparentShader::onCreateContext(const ContextRec& rec,
15                                                        void* storage) const {
16    return SkNEW_PLACEMENT_ARGS(storage, TransparentShaderContext, (*this, rec));
17}
18
19size_t SkTransparentShader::contextSize() const {
20    return sizeof(TransparentShaderContext);
21}
22
23SkTransparentShader::TransparentShaderContext::TransparentShaderContext(
24        const SkTransparentShader& shader, const ContextRec& rec)
25    : INHERITED(shader, rec)
26    , fDevice(rec.fDevice) {}
27
28SkTransparentShader::TransparentShaderContext::~TransparentShaderContext() {}
29
30uint32_t SkTransparentShader::TransparentShaderContext::getFlags() const {
31    uint32_t flags = this->INHERITED::getFlags();
32
33    switch (fDevice->colorType()) {
34        case kRGB_565_SkColorType:
35            flags |= kHasSpan16_Flag;
36            if (this->getPaintAlpha() == 255)
37                flags |= kOpaqueAlpha_Flag;
38            break;
39        case kN32_SkColorType:
40            if (this->getPaintAlpha() == 255 && fDevice->isOpaque())
41                flags |= kOpaqueAlpha_Flag;
42            break;
43        default:
44            break;
45    }
46    return flags;
47}
48
49void SkTransparentShader::TransparentShaderContext::shadeSpan(int x, int y, SkPMColor span[],
50                                                              int count) {
51    unsigned scale = SkAlpha255To256(this->getPaintAlpha());
52
53    switch (fDevice->colorType()) {
54        case kN32_SkColorType:
55            if (scale == 256) {
56                SkPMColor* src = fDevice->getAddr32(x, y);
57                if (src != span) {
58                    memcpy(span, src, count * sizeof(SkPMColor));
59                }
60            } else {
61                const SkPMColor* src = fDevice->getAddr32(x, y);
62                for (int i = count - 1; i >= 0; --i) {
63                    span[i] = SkAlphaMulQ(src[i], scale);
64                }
65            }
66            break;
67        case kRGB_565_SkColorType: {
68            const uint16_t* src = fDevice->getAddr16(x, y);
69            if (scale == 256) {
70                for (int i = count - 1; i >= 0; --i) {
71                    span[i] = SkPixel16ToPixel32(src[i]);
72                }
73            } else {
74                unsigned alpha = this->getPaintAlpha();
75                for (int i = count - 1; i >= 0; --i) {
76                    uint16_t c = src[i];
77                    unsigned r = SkPacked16ToR32(c);
78                    unsigned g = SkPacked16ToG32(c);
79                    unsigned b = SkPacked16ToB32(c);
80
81                    span[i] = SkPackARGB32( alpha,
82                                            SkAlphaMul(r, scale),
83                                            SkAlphaMul(g, scale),
84                                            SkAlphaMul(b, scale));
85                }
86            }
87            break;
88        }
89        case kAlpha_8_SkColorType: {
90            const uint8_t* src = fDevice->getAddr8(x, y);
91            if (scale == 256) {
92                for (int i = count - 1; i >= 0; --i) {
93                    span[i] = SkPackARGB32(src[i], 0, 0, 0);
94                }
95            } else {
96                for (int i = count - 1; i >= 0; --i) {
97                    span[i] = SkPackARGB32(SkAlphaMul(src[i], scale), 0, 0, 0);
98                }
99            }
100            break;
101        }
102        default:
103            SkDEBUGFAIL("colorType not supported as a destination device");
104            break;
105    }
106}
107
108void SkTransparentShader::TransparentShaderContext::shadeSpan16(int x, int y, uint16_t span[],
109                                                                int count) {
110    SkASSERT(fDevice->colorType() == kRGB_565_SkColorType);
111
112    uint16_t* src = fDevice->getAddr16(x, y);
113    if (src != span) {
114        memcpy(span, src, count << 1);
115    }
116}
117
118#ifndef SK_IGNORE_TO_STRING
119void SkTransparentShader::toString(SkString* str) const {
120    str->append("SkTransparentShader: (");
121
122    this->INHERITED::toString(str);
123
124    str->append(")");
125}
126#endif
127