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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.
#ifndef LIB_JXL_FRAME_DIMENSIONS_H_
#define LIB_JXL_FRAME_DIMENSIONS_H_
// FrameDimensions struct, block and group dimensions constants.
#include <cstddef>
#include "lib/jxl/base/common.h"
#include "lib/jxl/base/rect.h"
namespace jxl {
// Some enums and typedefs used by more than one header file.
// Block is the square grid of pixels to which an "energy compaction"
// transformation (e.g. DCT) is applied. Each block has its own AC quantizer.
constexpr size_t kBlockDim = 8;
constexpr size_t kDCTBlockSize = kBlockDim * kBlockDim;
constexpr size_t kGroupDim = 256;
static_assert(kGroupDim % kBlockDim == 0,
"Group dim should be divisible by block dim");
constexpr size_t kGroupDimInBlocks = kGroupDim / kBlockDim;
// Dimensions of a frame, in pixels, and other derived dimensions.
// Computed from FrameHeader.
// TODO(veluca): add extra channels.
struct FrameDimensions {
void Set(size_t xsize, size_t ysize, size_t group_size_shift,
size_t max_hshift, size_t max_vshift, bool modular_mode,
size_t upsampling) {
group_dim = (kGroupDim >> 1) << group_size_shift;
dc_group_dim = group_dim * kBlockDim;
xsize_upsampled = xsize;
ysize_upsampled = ysize;
this->xsize = DivCeil(xsize, upsampling);
this->ysize = DivCeil(ysize, upsampling);
xsize_blocks = DivCeil(this->xsize, kBlockDim << max_hshift) << max_hshift;
ysize_blocks = DivCeil(this->ysize, kBlockDim << max_vshift) << max_vshift;
xsize_padded = xsize_blocks * kBlockDim;
ysize_padded = ysize_blocks * kBlockDim;
if (modular_mode) {
// Modular mode doesn't have any padding.
xsize_padded = this->xsize;
ysize_padded = this->ysize;
}
xsize_upsampled_padded = xsize_padded * upsampling;
ysize_upsampled_padded = ysize_padded * upsampling;
xsize_groups = DivCeil(this->xsize, group_dim);
ysize_groups = DivCeil(this->ysize, group_dim);
xsize_dc_groups = DivCeil(xsize_blocks, group_dim);
ysize_dc_groups = DivCeil(ysize_blocks, group_dim);
num_groups = xsize_groups * ysize_groups;
num_dc_groups = xsize_dc_groups * ysize_dc_groups;
}
Rect GroupRect(size_t group_index) const {
const size_t gx = group_index % xsize_groups;
const size_t gy = group_index / xsize_groups;
const Rect rect(gx * group_dim, gy * group_dim, group_dim, group_dim, xsize,
ysize);
return rect;
}
Rect BlockGroupRect(size_t group_index) const {
const size_t gx = group_index % xsize_groups;
const size_t gy = group_index / xsize_groups;
const Rect rect(gx * (group_dim >> 3), gy * (group_dim >> 3),
group_dim >> 3, group_dim >> 3, xsize_blocks, ysize_blocks);
return rect;
}
Rect DCGroupRect(size_t group_index) const {
const size_t gx = group_index % xsize_dc_groups;
const size_t gy = group_index / xsize_dc_groups;
const Rect rect(gx * group_dim, gy * group_dim, group_dim, group_dim,
xsize_blocks, ysize_blocks);
return rect;
}
// Image size without any upsampling, i.e. original_size / upsampling.
size_t xsize;
size_t ysize;
// Original image size.
size_t xsize_upsampled;
size_t ysize_upsampled;
// Image size after upsampling the padded image.
size_t xsize_upsampled_padded;
size_t ysize_upsampled_padded;
// Image size after padding to a multiple of kBlockDim (if VarDCT mode).
size_t xsize_padded;
size_t ysize_padded;
// Image size in kBlockDim blocks.
size_t xsize_blocks;
size_t ysize_blocks;
// Image size in number of groups.
size_t xsize_groups;
size_t ysize_groups;
// Image size in number of DC groups.
size_t xsize_dc_groups;
size_t ysize_dc_groups;
// Number of AC or DC groups.
size_t num_groups;
size_t num_dc_groups;
// Size of a group.
size_t group_dim;
size_t dc_group_dim;
};
} // namespace jxl
#endif // LIB_JXL_FRAME_DIMENSIONS_H_