1/*
2 * Copyright 2018 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 "include/core/SkCanvas.h"
9#include "include/core/SkString.h"
10#include "include/effects/SkShaderMaskFilter.h"
11#include "src/core/SkMaskFilterBase.h"
12#include "src/core/SkReadBuffer.h"
13#include "src/shaders/SkShaderBase.h"
14
15class SkShaderMF : public SkMaskFilterBase {
16public:
17 SkShaderMF(sk_sp<SkShader> shader) : fShader(std::move(shader)) {}
18
19 SkMask::Format getFormat() const override { return SkMask::kA8_Format; }
20
21 bool filterMask(SkMask* dst, const SkMask& src, const SkMatrix&,
22 SkIPoint* margin) const override;
23
24 void computeFastBounds(const SkRect& src, SkRect* dst) const override {
25 *dst = src;
26 }
27
28 bool asABlur(BlurRec*) const override { return false; }
29
30protected:
31#if SK_SUPPORT_GPU
32 std::unique_ptr<GrFragmentProcessor> onAsFragmentProcessor(const GrFPArgs&) const override;
33 bool onHasFragmentProcessor() const override;
34#endif
35
36private:
37 SK_FLATTENABLE_HOOKS(SkShaderMF)
38
39 sk_sp<SkShader> fShader;
40
41 SkShaderMF(SkReadBuffer&);
42 void flatten(SkWriteBuffer&) const override;
43
44 friend class SkShaderMaskFilter;
45
46 typedef SkMaskFilter INHERITED;
47};
48
49sk_sp<SkFlattenable> SkShaderMF::CreateProc(SkReadBuffer& buffer) {
50 return SkShaderMaskFilter::Make(buffer.readShader());
51}
52
53void SkShaderMF::flatten(SkWriteBuffer& buffer) const {
54 buffer.writeFlattenable(fShader.get());
55}
56
57static void rect_memcpy(void* dst, size_t dstRB, const void* src, size_t srcRB,
58 size_t copyBytes, int rows) {
59 for (int i = 0; i < rows; ++i) {
60 memcpy(dst, src, copyBytes);
61 dst = (char*)dst + dstRB;
62 src = (const char*)src + srcRB;
63 }
64}
65
66bool SkShaderMF::filterMask(SkMask* dst, const SkMask& src, const SkMatrix& ctm,
67 SkIPoint* margin) const {
68 if (src.fFormat != SkMask::kA8_Format) {
69 return false;
70 }
71
72 if (margin) {
73 margin->set(0, 0);
74 }
75 dst->fBounds = src.fBounds;
76 dst->fRowBytes = src.fBounds.width(); // need alignment?
77 dst->fFormat = SkMask::kA8_Format;
78
79 if (src.fImage == nullptr) {
80 dst->fImage = nullptr;
81 return true;
82 }
83 size_t size = dst->computeImageSize();
84 if (0 == size) {
85 return false; // too big to allocate, abort
86 }
87
88 // Allocate and initialize dst image with a copy of the src image
89 dst->fImage = SkMask::AllocImage(size);
90 rect_memcpy(dst->fImage, dst->fRowBytes, src.fImage, src.fRowBytes,
91 src.fBounds.width() * sizeof(uint8_t), src.fBounds.height());
92
93 // Now we have a dst-mask, just need to setup a canvas and draw into it
94 SkBitmap bitmap;
95 if (!bitmap.installMaskPixels(*dst)) {
96 return false;
97 }
98
99 SkPaint paint;
100 paint.setShader(fShader);
101 paint.setFilterQuality(SkFilterQuality::kLow_SkFilterQuality);
102 // this blendmode is the trick: we only draw the shader where the mask is
103 paint.setBlendMode(SkBlendMode::kSrcIn);
104
105 SkCanvas canvas(bitmap);
106 canvas.translate(-SkIntToScalar(dst->fBounds.fLeft), -SkIntToScalar(dst->fBounds.fTop));
107 canvas.concat(ctm);
108 canvas.drawPaint(paint);
109 return true;
110}
111
112///////////////////////////////////////////////////////////////////////////////////////////////////
113#if SK_SUPPORT_GPU
114#include "src/gpu/GrFragmentProcessor.h"
115
116std::unique_ptr<GrFragmentProcessor> SkShaderMF::onAsFragmentProcessor(const GrFPArgs& args) const {
117 return GrFragmentProcessor::MulInputByChildAlpha(as_SB(fShader)->asFragmentProcessor(args));
118}
119
120bool SkShaderMF::onHasFragmentProcessor() const {
121 return true;
122}
123
124#endif
125///////////////////////////////////////////////////////////////////////////////////////////////////
126
127sk_sp<SkMaskFilter> SkShaderMaskFilter::Make(sk_sp<SkShader> shader) {
128 return shader ? sk_sp<SkMaskFilter>(new SkShaderMF(std::move(shader))) : nullptr;
129}
130
131void SkShaderMaskFilter::RegisterFlattenables() { SK_REGISTER_FLATTENABLE(SkShaderMF); }
132