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/*
* Copyright 2016 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkRGBAToYUV.h"
#include "SkCanvas.h"
#include "SkColorMatrixFilterRowMajor255.h"
#include "SkImage.h"
#include "SkPaint.h"
#include "SkSurface.h"
bool SkRGBAToYUV(const SkImage* image, const SkISize sizes[3], void* const planes[3],
const size_t rowBytes[3], SkYUVColorSpace colorSpace) {
// Matrices that go from RGBA to YUV.
static const SkScalar kYUVColorSpaceInvMatrices[][15] = {
// kJPEG_SkYUVColorSpace
{ 0.299001f, 0.586998f, 0.114001f, 0.f, 0.0000821798f * 255.f,
-0.168736f, -0.331263f, 0.499999f, 0.f, 0.499954f * 255.f,
0.499999f, -0.418686f, -0.0813131f, 0.f, 0.499941f * 255.f},
// kRec601_SkYUVColorSpace
{ 0.256951f, 0.504421f, 0.0977346f, 0.f, 0.0625f * 255.f,
-0.148212f, -0.290954f, 0.439166f, 0.f, 0.5f * 255.f,
0.439166f, -0.367886f, -0.0712802f, 0.f, 0.5f * 255.f},
// kRec709_SkYUVColorSpace
{ 0.182663f, 0.614473f, 0.061971f, 0.f, 0.0625f * 255.f,
-0.100672f, -0.338658f, 0.43933f, 0.f, 0.5f * 255.f,
0.439142f, -0.39891f, -0.040231f, 0.f, 0.5f * 255.f},
};
static_assert(kLastEnum_SkYUVColorSpace == 2, "yuv color matrix array problem");
static_assert(kJPEG_SkYUVColorSpace == 0, "yuv color matrix array problem");
static_assert(kRec601_SkYUVColorSpace == 1, "yuv color matrix array problem");
static_assert(kRec709_SkYUVColorSpace == 2, "yuv color matrix array problem");
for (int i = 0; i < 3; ++i) {
size_t rb = rowBytes[i] ? rowBytes[i] : sizes[i].fWidth;
auto surface(SkSurface::MakeRasterDirect(
SkImageInfo::MakeA8(sizes[i].fWidth, sizes[i].fHeight), planes[i], rb));
if (!surface) {
return false;
}
SkPaint paint;
paint.setFilterQuality(kLow_SkFilterQuality);
paint.setXfermodeMode(SkXfermode::kSrc_Mode);
int rowStartIdx = 5 * i;
const SkScalar* row = kYUVColorSpaceInvMatrices[colorSpace] + rowStartIdx;
paint.setColorFilter(
SkColorMatrixFilterRowMajor255::MakeSingleChannelOutput(row));
surface->getCanvas()->drawImageRect(image, SkIRect::MakeWH(image->width(), image->height()),
SkRect::MakeIWH(surface->width(), surface->height()),
&paint);
}
return true;
}
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