/*
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* Copyright 2018 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#include "SkCanvas.h"
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#include "SkMaskFilterBase.h"
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#include "SkReadBuffer.h"
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#include "SkShaderMaskFilter.h"
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#include "SkShaderBase.h"
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#include "SkString.h"
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class SkShaderMF : public SkMaskFilterBase {
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public:
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SkShaderMF(sk_sp<SkShader> shader) : fShader(std::move(shader)) {}
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SkMask::Format getFormat() const override { return SkMask::kA8_Format; }
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bool filterMask(SkMask* dst, const SkMask& src, const SkMatrix&,
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SkIPoint* margin) const override;
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void computeFastBounds(const SkRect& src, SkRect* dst) const override {
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*dst = src;
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}
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bool asABlur(BlurRec*) const override { return false; }
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protected:
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#if SK_SUPPORT_GPU
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std::unique_ptr<GrFragmentProcessor> onAsFragmentProcessor(const GrFPArgs&) const override;
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bool onHasFragmentProcessor() const override;
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#endif
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private:
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SK_FLATTENABLE_HOOKS(SkShaderMF)
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sk_sp<SkShader> fShader;
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SkShaderMF(SkReadBuffer&);
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void flatten(SkWriteBuffer&) const override;
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friend class SkShaderMaskFilter;
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typedef SkMaskFilter INHERITED;
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};
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sk_sp<SkFlattenable> SkShaderMF::CreateProc(SkReadBuffer& buffer) {
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return SkShaderMaskFilter::Make(buffer.readShader());
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}
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void SkShaderMF::flatten(SkWriteBuffer& buffer) const {
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buffer.writeFlattenable(fShader.get());
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}
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static void rect_memcpy(void* dst, size_t dstRB, const void* src, size_t srcRB,
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size_t copyBytes, int rows) {
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for (int i = 0; i < rows; ++i) {
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memcpy(dst, src, copyBytes);
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dst = (char*)dst + dstRB;
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src = (const char*)src + srcRB;
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}
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}
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bool SkShaderMF::filterMask(SkMask* dst, const SkMask& src, const SkMatrix& ctm,
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SkIPoint* margin) const {
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if (src.fFormat != SkMask::kA8_Format) {
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return false;
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}
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if (margin) {
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margin->set(0, 0);
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}
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dst->fBounds = src.fBounds;
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dst->fRowBytes = src.fBounds.width(); // need alignment?
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dst->fFormat = SkMask::kA8_Format;
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if (src.fImage == nullptr) {
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dst->fImage = nullptr;
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return true;
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}
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size_t size = dst->computeImageSize();
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if (0 == size) {
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return false; // too big to allocate, abort
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}
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// Allocate and initialize dst image with a copy of the src image
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dst->fImage = SkMask::AllocImage(size);
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rect_memcpy(dst->fImage, dst->fRowBytes, src.fImage, src.fRowBytes,
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src.fBounds.width() * sizeof(uint8_t), src.fBounds.height());
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// Now we have a dst-mask, just need to setup a canvas and draw into it
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SkBitmap bitmap;
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if (!bitmap.installMaskPixels(*dst)) {
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return false;
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}
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SkPaint paint;
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paint.setShader(fShader);
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paint.setFilterQuality(SkFilterQuality::kLow_SkFilterQuality);
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// this blendmode is the trick: we only draw the shader where the mask is
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paint.setBlendMode(SkBlendMode::kSrcIn);
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SkCanvas canvas(bitmap);
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canvas.translate(-SkIntToScalar(dst->fBounds.fLeft), -SkIntToScalar(dst->fBounds.fTop));
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canvas.concat(ctm);
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canvas.drawPaint(paint);
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return true;
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}
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///////////////////////////////////////////////////////////////////////////////////////////////////
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#if SK_SUPPORT_GPU
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#include "GrFragmentProcessor.h"
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std::unique_ptr<GrFragmentProcessor> SkShaderMF::onAsFragmentProcessor(const GrFPArgs& args) const {
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return GrFragmentProcessor::MulInputByChildAlpha(as_SB(fShader)->asFragmentProcessor(args));
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}
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bool SkShaderMF::onHasFragmentProcessor() const {
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return true;
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}
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#endif
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///////////////////////////////////////////////////////////////////////////////////////////////////
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sk_sp<SkMaskFilter> SkShaderMaskFilter::Make(sk_sp<SkShader> shader) {
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return shader ? sk_sp<SkMaskFilter>(new SkShaderMF(std::move(shader))) : nullptr;
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}
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void SkShaderMaskFilter::RegisterFlattenables() { SK_REGISTER_FLATTENABLE(SkShaderMF); }
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