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image_ops.h (10162B)

---

// 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_IMAGE_OPS_H_
#define LIB_JXL_IMAGE_OPS_H_

// Operations on images.

#include <jxl/memory_manager.h>

#include <algorithm>
#include <cstddef>
#include <cstdint>
#include <limits>

#include "lib/jxl/base/compiler_specific.h"
#include "lib/jxl/base/rect.h"
#include "lib/jxl/base/status.h"
#include "lib/jxl/frame_dimensions.h"
#include "lib/jxl/image.h"

namespace jxl {

// Works for mixed image-like argument types.
template <class Image1, class Image2>
bool SameSize(const Image1& image1, const Image2& image2) {
 return image1.xsize() == image2.xsize() && image1.ysize() == image2.ysize();
}

template <typename T>
Status CopyImageTo(const Plane<T>& from, Plane<T>* JXL_RESTRICT to) {
 JXL_ENSURE(SameSize(from, *to));
 if (from.ysize() == 0 || from.xsize() == 0) return true;
 for (size_t y = 0; y < from.ysize(); ++y) {
   const T* JXL_RESTRICT row_from = from.ConstRow(y);
   T* JXL_RESTRICT row_to = to->Row(y);
   memcpy(row_to, row_from, from.xsize() * sizeof(T));
 }
 return true;
}

// Copies `from:rect_from` to `to:rect_to`.
template <typename T>
Status CopyImageTo(const Rect& rect_from, const Plane<T>& from,
                  const Rect& rect_to, Plane<T>* JXL_RESTRICT to) {
 JXL_ENSURE(SameSize(rect_from, rect_to));
 JXL_ENSURE(rect_from.IsInside(from));
 JXL_ENSURE(rect_to.IsInside(*to));
 if (rect_from.xsize() == 0) return true;
 for (size_t y = 0; y < rect_from.ysize(); ++y) {
   const T* JXL_RESTRICT row_from = rect_from.ConstRow(from, y);
   T* JXL_RESTRICT row_to = rect_to.Row(to, y);
   memcpy(row_to, row_from, rect_from.xsize() * sizeof(T));
 }
 return true;
}

// Copies `from:rect_from` to `to:rect_to`.
template <typename T>
Status CopyImageTo(const Rect& rect_from, const Image3<T>& from,
                  const Rect& rect_to, Image3<T>* JXL_RESTRICT to) {
 JXL_ENSURE(SameSize(rect_from, rect_to));
 for (size_t c = 0; c < 3; c++) {
   JXL_RETURN_IF_ERROR(
       CopyImageTo(rect_from, from.Plane(c), rect_to, &to->Plane(c)));
 }
 return true;
}

template <typename T, typename U>
Status ConvertPlaneAndClamp(const Rect& rect_from, const Plane<T>& from,
                           const Rect& rect_to, Plane<U>* JXL_RESTRICT to) {
 JXL_ENSURE(SameSize(rect_from, rect_to));
 using M = decltype(T() + U());
 for (size_t y = 0; y < rect_to.ysize(); ++y) {
   const T* JXL_RESTRICT row_from = rect_from.ConstRow(from, y);
   U* JXL_RESTRICT row_to = rect_to.Row(to, y);
   for (size_t x = 0; x < rect_to.xsize(); ++x) {
     row_to[x] =
         std::min<M>(std::max<M>(row_from[x], std::numeric_limits<U>::min()),
                     std::numeric_limits<U>::max());
   }
 }
 return true;
}

// Copies `from` to `to`.
template <typename T>
Status CopyImageTo(const T& from, T* JXL_RESTRICT to) {
 return CopyImageTo(Rect(from), from, Rect(*to), to);
}

// Copies `from:rect_from` to `to:rect_to`; also copies `padding` pixels of
// border around `from:rect_from`, in all directions, whenever they are inside
// the first image.
template <typename T>
Status CopyImageToWithPadding(const Rect& from_rect, const T& from,
                             size_t padding, const Rect& to_rect, T* to) {
 size_t xextra0 = std::min(padding, from_rect.x0());
 size_t xextra1 =
     std::min(padding, from.xsize() - from_rect.x0() - from_rect.xsize());
 size_t yextra0 = std::min(padding, from_rect.y0());
 size_t yextra1 =
     std::min(padding, from.ysize() - from_rect.y0() - from_rect.ysize());
 JXL_ENSURE(to_rect.x0() >= xextra0);
 JXL_ENSURE(to_rect.y0() >= yextra0);

 return CopyImageTo(Rect(from_rect.x0() - xextra0, from_rect.y0() - yextra0,
                         from_rect.xsize() + xextra0 + xextra1,
                         from_rect.ysize() + yextra0 + yextra1),
                    from,
                    Rect(to_rect.x0() - xextra0, to_rect.y0() - yextra0,
                         to_rect.xsize() + xextra0 + xextra1,
                         to_rect.ysize() + yextra0 + yextra1),
                    to);
}

// Returns linear combination of two grayscale images.
template <typename T>
StatusOr<Plane<T>> LinComb(const T lambda1, const Plane<T>& image1,
                          const T lambda2, const Plane<T>& image2) {
 const size_t xsize = image1.xsize();
 const size_t ysize = image1.ysize();
 JXL_ENSURE(xsize == image2.xsize());
 JXL_ENSURE(ysize == image2.ysize());
 JxlMemoryManager* memory_manager = image1.memory_manager();
 JXL_ASSIGN_OR_RETURN(Plane<T> out,
                      Plane<T>::Create(memory_manager, xsize, ysize));
 for (size_t y = 0; y < ysize; ++y) {
   const T* const JXL_RESTRICT row1 = image1.Row(y);
   const T* const JXL_RESTRICT row2 = image2.Row(y);
   T* const JXL_RESTRICT row_out = out.Row(y);
   for (size_t x = 0; x < xsize; ++x) {
     row_out[x] = lambda1 * row1[x] + lambda2 * row2[x];
   }
 }
 return out;
}

// Multiplies image by lambda in-place
template <typename T>
void ScaleImage(const T lambda, Plane<T>* image) {
 for (size_t y = 0; y < image->ysize(); ++y) {
   T* const JXL_RESTRICT row = image->Row(y);
   for (size_t x = 0; x < image->xsize(); ++x) {
     row[x] = lambda * row[x];
   }
 }
}

// Multiplies image by lambda in-place
template <typename T>
void ScaleImage(const T lambda, Image3<T>* image) {
 for (size_t c = 0; c < 3; ++c) {
   ScaleImage(lambda, &image->Plane(c));
 }
}

template <typename T>
void FillImage(const T value, Plane<T>* image) {
 for (size_t y = 0; y < image->ysize(); ++y) {
   T* const JXL_RESTRICT row = image->Row(y);
   for (size_t x = 0; x < image->xsize(); ++x) {
     row[x] = value;
   }
 }
}

template <typename T>
void ZeroFillImage(Plane<T>* image) {
 if (image->xsize() == 0) return;
 for (size_t y = 0; y < image->ysize(); ++y) {
   T* const JXL_RESTRICT row = image->Row(y);
   memset(row, 0, image->xsize() * sizeof(T));
 }
}

// Mirrors out of bounds coordinates and returns valid coordinates unchanged.
// We assume the radius (distance outside the image) is small compared to the
// image size, otherwise this might not terminate.
// The mirror is outside the last column (border pixel is also replicated).
static inline int64_t Mirror(int64_t x, const int64_t xsize) {
 JXL_DASSERT(xsize != 0);

 // TODO(janwas): replace with branchless version
 while (x < 0 || x >= xsize) {
   if (x < 0) {
     x = -x - 1;
   } else {
     x = 2 * xsize - 1 - x;
   }
 }
 return x;
}

// Wrap modes for ensuring X/Y coordinates are in the valid range [0, size):

// Mirrors (repeating the edge pixel once). Useful for convolutions.
struct WrapMirror {
 JXL_INLINE int64_t operator()(const int64_t coord, const int64_t size) const {
   return Mirror(coord, size);
 }
};

// Returns the same coordinate: required for TFNode with Border(), or useful
// when we know "coord" is already valid (e.g. interior of an image).
struct WrapUnchanged {
 JXL_INLINE int64_t operator()(const int64_t coord, int64_t /*size*/) const {
   return coord;
 }
};

// Similar to Wrap* but for row pointers (reduces Row() multiplications).

class WrapRowMirror {
public:
 template <class ImageOrView>
 WrapRowMirror(const ImageOrView& image, size_t ysize)
     : first_row_(image.ConstRow(0)), last_row_(image.ConstRow(ysize - 1)) {}

 const float* operator()(const float* const JXL_RESTRICT row,
                         const int64_t stride) const {
   if (row < first_row_) {
     const int64_t num_before = first_row_ - row;
     // Mirrored; one row before => row 0, two before = row 1, ...
     return first_row_ + num_before - stride;
   }
   if (row > last_row_) {
     const int64_t num_after = row - last_row_;
     // Mirrored; one row after => last row, two after = last - 1, ...
     return last_row_ - num_after + stride;
   }
   return row;
 }

private:
 const float* const JXL_RESTRICT first_row_;
 const float* const JXL_RESTRICT last_row_;
};

struct WrapRowUnchanged {
 JXL_INLINE const float* operator()(const float* const JXL_RESTRICT row,
                                    int64_t /*stride*/) const {
   return row;
 }
};

// Computes the minimum and maximum pixel value.
template <typename T>
void ImageMinMax(const Plane<T>& image, T* const JXL_RESTRICT min,
                T* const JXL_RESTRICT max) {
 *min = std::numeric_limits<T>::max();
 *max = std::numeric_limits<T>::lowest();
 for (size_t y = 0; y < image.ysize(); ++y) {
   const T* const JXL_RESTRICT row = image.Row(y);
   for (size_t x = 0; x < image.xsize(); ++x) {
     *min = std::min(*min, row[x]);
     *max = std::max(*max, row[x]);
   }
 }
}

// Initializes all planes to the same "value".
template <typename T>
void FillImage(const T value, Image3<T>* image) {
 for (size_t c = 0; c < 3; ++c) {
   for (size_t y = 0; y < image->ysize(); ++y) {
     T* JXL_RESTRICT row = image->PlaneRow(c, y);
     for (size_t x = 0; x < image->xsize(); ++x) {
       row[x] = value;
     }
   }
 }
}

template <typename T>
void FillPlane(const T value, Plane<T>* image, Rect rect) {
 for (size_t y = 0; y < rect.ysize(); ++y) {
   T* JXL_RESTRICT row = rect.Row(image, y);
   for (size_t x = 0; x < rect.xsize(); ++x) {
     row[x] = value;
   }
 }
}

template <typename T>
void ZeroFillImage(Image3<T>* image) {
 for (size_t c = 0; c < 3; ++c) {
   for (size_t y = 0; y < image->ysize(); ++y) {
     T* JXL_RESTRICT row = image->PlaneRow(c, y);
     if (image->xsize() != 0) memset(row, 0, image->xsize() * sizeof(T));
   }
 }
}

// Same as above, but operates in-place. Assumes that the `in` image was
// allocated large enough.
Status PadImageToBlockMultipleInPlace(Image3F* JXL_RESTRICT in,
                                     size_t block_dim = kBlockDim);

// Downsamples an image by a given factor.
StatusOr<Image3F> DownsampleImage(const Image3F& opsin, size_t factor);
StatusOr<ImageF> DownsampleImage(const ImageF& image, size_t factor);

}  // namespace jxl

#endif  // LIB_JXL_IMAGE_OPS_H_