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 "SkCanvas.h"
9 #include "SkMaskFilterBase.h"
10 #include "SkReadBuffer.h"
11 #include "SkShaderMaskFilter.h"
12 #include "SkShaderBase.h"
13 #include "SkString.h"
14
15 class SkShaderMF : public SkMaskFilterBase {
16 public:
SkShaderMF(sk_sp<SkShader> shader)17 SkShaderMF(sk_sp<SkShader> shader) : fShader(std::move(shader)) {}
18
getFormat() const19 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
computeFastBounds(const SkRect & src,SkRect * dst) const24 void computeFastBounds(const SkRect& src, SkRect* dst) const override {
25 *dst = src;
26 }
27
asABlur(BlurRec *) const28 bool asABlur(BlurRec*) const override { return false; }
29
30 protected:
31 #if SK_SUPPORT_GPU
32 std::unique_ptr<GrFragmentProcessor> onAsFragmentProcessor(const GrFPArgs&) const override;
33 bool onHasFragmentProcessor() const override;
34 #endif
35
36 private:
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
CreateProc(SkReadBuffer & buffer)49 sk_sp<SkFlattenable> SkShaderMF::CreateProc(SkReadBuffer& buffer) {
50 return SkShaderMaskFilter::Make(buffer.readShader());
51 }
52
flatten(SkWriteBuffer & buffer) const53 void SkShaderMF::flatten(SkWriteBuffer& buffer) const {
54 buffer.writeFlattenable(fShader.get());
55 }
56
rect_memcpy(void * dst,size_t dstRB,const void * src,size_t srcRB,size_t copyBytes,int rows)57 static 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
filterMask(SkMask * dst,const SkMask & src,const SkMatrix & ctm,SkIPoint * margin) const66 bool 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 "GrFragmentProcessor.h"
115
onAsFragmentProcessor(const GrFPArgs & args) const116 std::unique_ptr<GrFragmentProcessor> SkShaderMF::onAsFragmentProcessor(const GrFPArgs& args) const {
117 return GrFragmentProcessor::MulInputByChildAlpha(as_SB(fShader)->asFragmentProcessor(args));
118 }
119
onHasFragmentProcessor() const120 bool SkShaderMF::onHasFragmentProcessor() const {
121 return true;
122 }
123
124 #endif
125 ///////////////////////////////////////////////////////////////////////////////////////////////////
126
Make(sk_sp<SkShader> shader)127 sk_sp<SkMaskFilter> SkShaderMaskFilter::Make(sk_sp<SkShader> shader) {
128 return shader ? sk_sp<SkMaskFilter>(new SkShaderMF(std::move(shader))) : nullptr;
129 }
130
RegisterFlattenables()131 void SkShaderMaskFilter::RegisterFlattenables() { SK_REGISTER_FLATTENABLE(SkShaderMF); }
132