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// Copyright (c) the JPEG XL Project Authors. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
#include "lib/jxl/image_ops.h"
#include <cstddef>
#include <cstring>
#include "lib/jxl/base/common.h"
#include "lib/jxl/base/compiler_specific.h"
#include "lib/jxl/base/status.h"
#include "lib/jxl/frame_dimensions.h"
#include "lib/jxl/image.h"
namespace jxl {
Status PadImageToBlockMultipleInPlace(Image3F* JXL_RESTRICT in,
size_t block_dim) {
const size_t xsize_orig = in->xsize();
const size_t ysize_orig = in->ysize();
const size_t xsize = RoundUpTo(xsize_orig, block_dim);
const size_t ysize = RoundUpTo(ysize_orig, block_dim);
// Expands image size to the originally-allocated size.
JXL_RETURN_IF_ERROR(in->ShrinkTo(xsize, ysize));
for (size_t c = 0; c < 3; c++) {
for (size_t y = 0; y < ysize_orig; y++) {
float* JXL_RESTRICT row = in->PlaneRow(c, y);
for (size_t x = xsize_orig; x < xsize; x++) {
row[x] = row[xsize_orig - 1];
}
}
const float* JXL_RESTRICT row_src = in->ConstPlaneRow(c, ysize_orig - 1);
for (size_t y = ysize_orig; y < ysize; y++) {
memcpy(in->PlaneRow(c, y), row_src, xsize * sizeof(float));
}
}
return true;
}
static Status DoDownsampleImage(const ImageF& input, size_t factor,
ImageF* output) {
JXL_ENSURE(factor != 1);
JXL_RETURN_IF_ERROR(output->ShrinkTo(DivCeil(input.xsize(), factor),
DivCeil(input.ysize(), factor)));
size_t in_stride = input.PixelsPerRow();
for (size_t y = 0; y < output->ysize(); y++) {
float* row_out = output->Row(y);
const float* row_in = input.Row(factor * y);
for (size_t x = 0; x < output->xsize(); x++) {
size_t cnt = 0;
float sum = 0;
for (size_t iy = 0; iy < factor && iy + factor * y < input.ysize();
iy++) {
for (size_t ix = 0; ix < factor && ix + factor * x < input.xsize();
ix++) {
sum += row_in[iy * in_stride + x * factor + ix];
cnt++;
}
}
row_out[x] = sum / cnt;
}
}
return true;
}
StatusOr<ImageF> DownsampleImage(const ImageF& image, size_t factor) {
ImageF downsampled;
// Allocate extra space to avoid a reallocation when padding.
JxlMemoryManager* memory_manager = image.memory_manager();
JXL_ASSIGN_OR_RETURN(
downsampled,
ImageF::Create(memory_manager, DivCeil(image.xsize(), factor) + kBlockDim,
DivCeil(image.ysize(), factor) + kBlockDim));
JXL_RETURN_IF_ERROR(DoDownsampleImage(image, factor, &downsampled));
return downsampled;
}
StatusOr<Image3F> DownsampleImage(const Image3F& opsin, size_t factor) {
JXL_ENSURE(factor != 1);
// Allocate extra space to avoid a reallocation when padding.
Image3F downsampled;
JxlMemoryManager* memory_manager = opsin.memory_manager();
JXL_ASSIGN_OR_RETURN(
downsampled, Image3F::Create(memory_manager,
DivCeil(opsin.xsize(), factor) + kBlockDim,
DivCeil(opsin.ysize(), factor) + kBlockDim));
JXL_RETURN_IF_ERROR(downsampled.ShrinkTo(downsampled.xsize() - kBlockDim,
downsampled.ysize() - kBlockDim));
for (size_t c = 0; c < 3; c++) {
JXL_RETURN_IF_ERROR(
DoDownsampleImage(opsin.Plane(c), factor, &downsampled.Plane(c)));
}
return downsampled;
}
} // namespace jxl