252 lines
7.4 KiB
C++
252 lines
7.4 KiB
C++
/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "ImageScaling.h"
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#include "2D.h"
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#include "DataSurfaceHelpers.h"
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#include <math.h>
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#include <algorithm>
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using namespace std;
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namespace mozilla {
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namespace gfx {
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inline uint32_t Avg2x2(uint32_t a, uint32_t b, uint32_t c, uint32_t d)
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{
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// Prepare half-adder work
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uint32_t sum = a ^ b ^ c;
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uint32_t carry = (a & b) | (a & c) | (b & c);
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// Before shifting, mask lower order bits of each byte to avoid underflow.
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uint32_t mask = 0xfefefefe;
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// Add d to sum and divide by 2.
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sum = (((sum ^ d) & mask) >> 1) + (sum & d);
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// Sum is now shifted into place relative to carry, add them together.
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return (((sum ^ carry) & mask) >> 1) + (sum & carry);
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}
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inline uint32_t Avg2(uint32_t a, uint32_t b)
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{
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// Prepare half-adder work
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uint32_t sum = a ^ b;
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uint32_t carry = (a & b);
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// Before shifting, mask lower order bits of each byte to avoid underflow.
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uint32_t mask = 0xfefefefe;
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// Add d to sum and divide by 2.
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return ((sum & mask) >> 1) + carry;
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}
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void
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ImageHalfScaler::ScaleForSize(const IntSize &aSize)
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{
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uint32_t horizontalDownscales = 0;
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uint32_t verticalDownscales = 0;
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IntSize scaleSize = mOrigSize;
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while ((scaleSize.height / 2) > aSize.height) {
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verticalDownscales++;
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scaleSize.height /= 2;
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}
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while ((scaleSize.width / 2) > aSize.width) {
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horizontalDownscales++;
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scaleSize.width /= 2;
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}
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if (scaleSize == mOrigSize) {
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return;
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}
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delete [] mDataStorage;
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IntSize internalSurfSize;
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internalSurfSize.width = max(scaleSize.width, mOrigSize.width / 2);
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internalSurfSize.height = max(scaleSize.height, mOrigSize.height / 2);
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size_t bufLen = 0;
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mStride = GetAlignedStride<16>(internalSurfSize.width, 4);
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if (mStride > 0) {
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// Allocate 15 bytes extra to make sure we can get 16 byte alignment. We
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// should add tools for this, see bug 751696.
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bufLen = BufferSizeFromStrideAndHeight(mStride, internalSurfSize.height, 15);
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}
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if (bufLen == 0) {
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mSize.SizeTo(0, 0);
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mDataStorage = nullptr;
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return;
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}
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mDataStorage = new uint8_t[bufLen];
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if (uintptr_t(mDataStorage) % 16) {
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// Our storage does not start at a 16-byte boundary. Make sure mData does!
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mData = (uint8_t*)(uintptr_t(mDataStorage) +
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(16 - (uintptr_t(mDataStorage) % 16)));
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} else {
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mData = mDataStorage;
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}
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mSize = scaleSize;
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/* The surface we sample from might not be even sized, if it's not we will
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* ignore the last row/column. This means we lose some data but it keeps the
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* code very simple. There's also no perfect answer that provides a better
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* solution.
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*/
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IntSize currentSampledSize = mOrigSize;
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uint32_t currentSampledStride = mOrigStride;
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uint8_t *currentSampledData = mOrigData;
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while (verticalDownscales && horizontalDownscales) {
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if (currentSampledSize.width % 2) {
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currentSampledSize.width -= 1;
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}
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if (currentSampledSize.height % 2) {
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currentSampledSize.height -= 1;
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}
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HalfImage2D(currentSampledData, currentSampledStride, currentSampledSize,
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mData, mStride);
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verticalDownscales--;
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horizontalDownscales--;
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currentSampledSize.width /= 2;
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currentSampledSize.height /= 2;
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currentSampledData = mData;
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currentSampledStride = mStride;
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}
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while (verticalDownscales) {
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if (currentSampledSize.height % 2) {
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currentSampledSize.height -= 1;
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}
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HalfImageVertical(currentSampledData, currentSampledStride, currentSampledSize,
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mData, mStride);
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verticalDownscales--;
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currentSampledSize.height /= 2;
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currentSampledData = mData;
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currentSampledStride = mStride;
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}
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while (horizontalDownscales) {
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if (currentSampledSize.width % 2) {
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currentSampledSize.width -= 1;
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}
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HalfImageHorizontal(currentSampledData, currentSampledStride, currentSampledSize,
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mData, mStride);
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horizontalDownscales--;
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currentSampledSize.width /= 2;
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currentSampledData = mData;
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currentSampledStride = mStride;
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}
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}
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void
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ImageHalfScaler::HalfImage2D(uint8_t *aSource, int32_t aSourceStride,
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const IntSize &aSourceSize, uint8_t *aDest,
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uint32_t aDestStride)
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{
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#ifdef USE_SSE2
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if (Factory::HasSSE2()) {
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HalfImage2D_SSE2(aSource, aSourceStride, aSourceSize, aDest, aDestStride);
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} else
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#endif
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{
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HalfImage2D_C(aSource, aSourceStride, aSourceSize, aDest, aDestStride);
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}
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}
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void
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ImageHalfScaler::HalfImageVertical(uint8_t *aSource, int32_t aSourceStride,
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const IntSize &aSourceSize, uint8_t *aDest,
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uint32_t aDestStride)
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{
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#ifdef USE_SSE2
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if (Factory::HasSSE2()) {
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HalfImageVertical_SSE2(aSource, aSourceStride, aSourceSize, aDest, aDestStride);
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} else
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#endif
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{
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HalfImageVertical_C(aSource, aSourceStride, aSourceSize, aDest, aDestStride);
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}
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}
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void
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ImageHalfScaler::HalfImageHorizontal(uint8_t *aSource, int32_t aSourceStride,
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const IntSize &aSourceSize, uint8_t *aDest,
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uint32_t aDestStride)
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{
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#ifdef USE_SSE2
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if (Factory::HasSSE2()) {
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HalfImageHorizontal_SSE2(aSource, aSourceStride, aSourceSize, aDest, aDestStride);
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} else
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#endif
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{
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HalfImageHorizontal_C(aSource, aSourceStride, aSourceSize, aDest, aDestStride);
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}
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}
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void
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ImageHalfScaler::HalfImage2D_C(uint8_t *aSource, int32_t aSourceStride,
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const IntSize &aSourceSize, uint8_t *aDest,
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uint32_t aDestStride)
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{
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for (int y = 0; y < aSourceSize.height; y += 2) {
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uint32_t *storage = (uint32_t*)(aDest + (y / 2) * aDestStride);
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for (int x = 0; x < aSourceSize.width; x += 2) {
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uint8_t *upperRow = aSource + (y * aSourceStride + x * 4);
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uint8_t *lowerRow = aSource + ((y + 1) * aSourceStride + x * 4);
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*storage++ = Avg2x2(*(uint32_t*)upperRow, *((uint32_t*)upperRow + 1),
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*(uint32_t*)lowerRow, *((uint32_t*)lowerRow + 1));
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}
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}
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}
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void
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ImageHalfScaler::HalfImageVertical_C(uint8_t *aSource, int32_t aSourceStride,
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const IntSize &aSourceSize, uint8_t *aDest,
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uint32_t aDestStride)
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{
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for (int y = 0; y < aSourceSize.height; y += 2) {
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uint32_t *storage = (uint32_t*)(aDest + (y / 2) * aDestStride);
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for (int x = 0; x < aSourceSize.width; x++) {
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uint32_t *upperRow = (uint32_t*)(aSource + (y * aSourceStride + x * 4));
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uint32_t *lowerRow = (uint32_t*)(aSource + ((y + 1) * aSourceStride + x * 4));
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*storage++ = Avg2(*upperRow, *lowerRow);
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}
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}
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}
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void
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ImageHalfScaler::HalfImageHorizontal_C(uint8_t *aSource, int32_t aSourceStride,
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const IntSize &aSourceSize, uint8_t *aDest,
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uint32_t aDestStride)
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{
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for (int y = 0; y < aSourceSize.height; y++) {
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uint32_t *storage = (uint32_t*)(aDest + y * aDestStride);
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for (int x = 0; x < aSourceSize.width; x+= 2) {
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uint32_t *pixels = (uint32_t*)(aSource + (y * aSourceStride + x * 4));
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*storage++ = Avg2(*pixels, *(pixels + 1));
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}
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}
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}
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} // namespace gfx
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} // namespace mozilla
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