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 "src/effects/SkShaderMaskFilterImpl.h"
9
10 #include "include/core/SkBitmap.h"
11 #include "include/core/SkBlendMode.h"
12 #include "include/core/SkCanvas.h"
13 #include "include/core/SkFlattenable.h"
14 #include "include/core/SkMaskFilter.h"
15 #include "include/core/SkPaint.h"
16 #include "include/core/SkPoint.h"
17 #include "include/core/SkRect.h"
18 #include "include/core/SkRefCnt.h"
19 #include "include/core/SkScalar.h"
20 #include "include/core/SkShader.h"
21 #include "include/effects/SkShaderMaskFilter.h"
22 #include "src/core/SkMask.h"
23 #include "src/core/SkReadBuffer.h"
24 #include "src/core/SkWriteBuffer.h"
25
26 #include <cstdint>
27 #include <cstring>
28 #include <utility>
29
30 class SkMatrix;
31
CreateProc(SkReadBuffer & buffer)32 sk_sp<SkFlattenable> SkShaderMaskFilterImpl::CreateProc(SkReadBuffer& buffer) {
33 return SkShaderMaskFilter::Make(buffer.readShader());
34 }
35
flatten(SkWriteBuffer & buffer) const36 void SkShaderMaskFilterImpl::flatten(SkWriteBuffer& buffer) const {
37 buffer.writeFlattenable(fShader.get());
38 }
39
rect_memcpy(void * dst,size_t dstRB,const void * src,size_t srcRB,size_t copyBytes,int rows)40 static void rect_memcpy(void* dst, size_t dstRB, const void* src, size_t srcRB,
41 size_t copyBytes, int rows) {
42 for (int i = 0; i < rows; ++i) {
43 memcpy(dst, src, copyBytes);
44 dst = (char*)dst + dstRB;
45 src = (const char*)src + srcRB;
46 }
47 }
48
filterMask(SkMaskBuilder * dst,const SkMask & src,const SkMatrix & ctm,SkIPoint * margin) const49 bool SkShaderMaskFilterImpl::filterMask(SkMaskBuilder* dst, const SkMask& src, const SkMatrix& ctm,
50 SkIPoint* margin) const {
51 if (src.fFormat != SkMask::kA8_Format) {
52 return false;
53 }
54
55 if (margin) {
56 margin->set(0, 0);
57 }
58 dst->bounds() = src.fBounds;
59 dst->rowBytes() = src.fBounds.width(); // need alignment?
60 dst->format() = SkMask::kA8_Format;
61
62 if (src.fImage == nullptr) {
63 dst->image() = nullptr;
64 return true;
65 }
66 size_t size = dst->computeImageSize();
67 if (0 == size) {
68 return false; // too big to allocate, abort
69 }
70
71 // Allocate and initialize dst image with a copy of the src image
72 dst->image() = SkMaskBuilder::AllocImage(size);
73 rect_memcpy(dst->image(), dst->fRowBytes, src.fImage, src.fRowBytes,
74 src.fBounds.width() * sizeof(uint8_t), src.fBounds.height());
75
76 // Now we have a dst-mask, just need to setup a canvas and draw into it
77 SkBitmap bitmap;
78 if (!bitmap.installMaskPixels(*dst)) {
79 return false;
80 }
81
82 SkPaint paint;
83 paint.setShader(fShader);
84 // this blendmode is the trick: we only draw the shader where the mask is
85 paint.setBlendMode(SkBlendMode::kSrcIn);
86
87 SkCanvas canvas(bitmap);
88 canvas.translate(-SkIntToScalar(dst->fBounds.fLeft), -SkIntToScalar(dst->fBounds.fTop));
89 canvas.concat(ctm);
90 canvas.drawPaint(paint);
91 return true;
92 }
93
Make(sk_sp<SkShader> shader)94 sk_sp<SkMaskFilter> SkShaderMaskFilter::Make(sk_sp<SkShader> shader) {
95 return shader ? sk_sp<SkMaskFilter>(new SkShaderMaskFilterImpl(std::move(shader))) : nullptr;
96 }
97
RegisterFlattenables()98 void SkShaderMaskFilter::RegisterFlattenables() {
99 SK_REGISTER_FLATTENABLE(SkShaderMaskFilterImpl);
100 // Previous name
101 SkFlattenable::Register("SkShaderMF", SkShaderMaskFilterImpl::CreateProc);
102 }
103