/*
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* Copyright 2011 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 "SkFixed.h"
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#include "SkReadBuffer.h"
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#include "SkString.h"
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#include "SkTableMaskFilter.h"
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#include "SkWriteBuffer.h"
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class SkTableMaskFilterImpl : public SkMaskFilterBase {
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public:
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explicit SkTableMaskFilterImpl(const uint8_t table[256]);
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SkMask::Format getFormat() const override;
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bool filterMask(SkMask*, const SkMask&, const SkMatrix&, SkIPoint*) const override;
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protected:
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~SkTableMaskFilterImpl() override;
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void flatten(SkWriteBuffer&) const override;
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private:
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SK_FLATTENABLE_HOOKS(SkTableMaskFilterImpl)
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SkTableMaskFilterImpl();
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uint8_t fTable[256];
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typedef SkMaskFilter INHERITED;
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};
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SkTableMaskFilterImpl::SkTableMaskFilterImpl() {
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for (int i = 0; i < 256; i++) {
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fTable[i] = i;
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}
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}
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SkTableMaskFilterImpl::SkTableMaskFilterImpl(const uint8_t table[256]) {
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memcpy(fTable, table, sizeof(fTable));
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}
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SkTableMaskFilterImpl::~SkTableMaskFilterImpl() {}
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bool SkTableMaskFilterImpl::filterMask(SkMask* dst, const SkMask& src,
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const SkMatrix&, 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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dst->fBounds = src.fBounds;
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dst->fRowBytes = SkAlign4(dst->fBounds.width());
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dst->fFormat = SkMask::kA8_Format;
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dst->fImage = nullptr;
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if (src.fImage) {
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dst->fImage = SkMask::AllocImage(dst->computeImageSize());
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const uint8_t* srcP = src.fImage;
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uint8_t* dstP = dst->fImage;
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const uint8_t* table = fTable;
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int dstWidth = dst->fBounds.width();
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int extraZeros = dst->fRowBytes - dstWidth;
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for (int y = dst->fBounds.height() - 1; y >= 0; --y) {
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for (int x = dstWidth - 1; x >= 0; --x) {
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dstP[x] = table[srcP[x]];
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}
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srcP += src.fRowBytes;
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// we can't just inc dstP by rowbytes, because if it has any
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// padding between its width and its rowbytes, we need to zero those
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// so that the bitters can read those safely if that is faster for
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// them
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dstP += dstWidth;
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for (int i = extraZeros - 1; i >= 0; --i) {
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*dstP++ = 0;
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}
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}
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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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return true;
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}
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SkMask::Format SkTableMaskFilterImpl::getFormat() const {
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return SkMask::kA8_Format;
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}
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void SkTableMaskFilterImpl::flatten(SkWriteBuffer& wb) const {
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wb.writeByteArray(fTable, 256);
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}
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sk_sp<SkFlattenable> SkTableMaskFilterImpl::CreateProc(SkReadBuffer& buffer) {
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uint8_t table[256];
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if (!buffer.readByteArray(table, 256)) {
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return nullptr;
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}
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return sk_sp<SkFlattenable>(SkTableMaskFilter::Create(table));
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}
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///////////////////////////////////////////////////////////////////////////////
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SkMaskFilter* SkTableMaskFilter::Create(const uint8_t table[256]) {
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return new SkTableMaskFilterImpl(table);
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}
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SkMaskFilter* SkTableMaskFilter::CreateGamma(SkScalar gamma) {
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uint8_t table[256];
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MakeGammaTable(table, gamma);
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return new SkTableMaskFilterImpl(table);
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}
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SkMaskFilter* SkTableMaskFilter::CreateClip(uint8_t min, uint8_t max) {
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uint8_t table[256];
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MakeClipTable(table, min, max);
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return new SkTableMaskFilterImpl(table);
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}
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void SkTableMaskFilter::MakeGammaTable(uint8_t table[256], SkScalar gamma) {
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const float dx = 1 / 255.0f;
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const float g = SkScalarToFloat(gamma);
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float x = 0;
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for (int i = 0; i < 256; i++) {
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// float ee = powf(x, g) * 255;
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table[i] = SkTPin(sk_float_round2int(powf(x, g) * 255), 0, 255);
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x += dx;
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}
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}
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void SkTableMaskFilter::MakeClipTable(uint8_t table[256], uint8_t min,
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uint8_t max) {
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if (0 == max) {
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max = 1;
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}
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if (min >= max) {
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min = max - 1;
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}
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SkASSERT(min < max);
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SkFixed scale = (1 << 16) * 255 / (max - min);
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memset(table, 0, min + 1);
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for (int i = min + 1; i < max; i++) {
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int value = SkFixedRoundToInt(scale * (i - min));
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SkASSERT(value <= 255);
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table[i] = value;
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}
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memset(table + max, 255, 256 - max);
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#if 0
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int j;
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for (j = 0; j < 256; j++) {
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if (table[j]) {
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break;
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}
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}
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SkDebugf("%d %d start [%d]", min, max, j);
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for (; j < 256; j++) {
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SkDebugf(" %d", table[j]);
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}
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SkDebugf("\n\n");
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#endif
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}
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