tor-browser

rect.h (6217B)

---

// 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_BASE_RECT_H_
#define LIB_JXL_BASE_RECT_H_

#include <algorithm>
#include <cstddef>
#include <cstdint>
#include <cstring>
#include <sstream>
#include <string>
#include <utility>  // std::move

#include "lib/jxl/base/compiler_specific.h"
#include "lib/jxl/base/status.h"

namespace jxl {

// Rectangular region in image(s). Factoring this out of Image instead of
// shifting the pointer by x0/y0 allows this to apply to multiple images with
// different resolutions (e.g. color transform and quantization field).
// Can compare using SameSize(rect1, rect2).
template <typename T>
class RectT {
public:
 // Most windows are xsize_max * ysize_max, except those on the borders where
 // begin + size_max > end.
 constexpr RectT(T xbegin, T ybegin, size_t xsize_max, size_t ysize_max,
                 T xend, T yend)
     : x0_(xbegin),
       y0_(ybegin),
       xsize_(ClampedSize(xbegin, xsize_max, xend)),
       ysize_(ClampedSize(ybegin, ysize_max, yend)) {}

 // Construct with origin and known size (typically from another Rect).
 constexpr RectT(T xbegin, T ybegin, size_t xsize, size_t ysize)
     : x0_(xbegin), y0_(ybegin), xsize_(xsize), ysize_(ysize) {}

 // Construct a rect that covers a whole image/plane/ImageBundle etc.
 template <typename ImageT>
 explicit RectT(const ImageT& image)
     : RectT(0, 0, image.xsize(), image.ysize()) {}

 RectT() : RectT(0, 0, 0, 0) {}

 RectT(const RectT&) = default;
 RectT& operator=(const RectT&) = default;

 // Construct a subrect that resides in an image/plane/ImageBundle etc.
 template <typename ImageT>
 RectT Crop(const ImageT& image) const {
   return Intersection(RectT(image));
 }

 // Construct a subrect that resides in the [0, ysize) x [0, xsize) region of
 // the current rect.
 RectT Crop(size_t area_xsize, size_t area_ysize) const {
   return Intersection(RectT(0, 0, area_xsize, area_ysize));
 }

 JXL_MUST_USE_RESULT RectT Intersection(const RectT& other) const {
   return RectT(std::max(x0_, other.x0_), std::max(y0_, other.y0_), xsize_,
                ysize_, std::min(x1(), other.x1()),
                std::min(y1(), other.y1()));
 }

 JXL_MUST_USE_RESULT RectT Translate(int64_t x_offset,
                                     int64_t y_offset) const {
   return RectT(x0_ + x_offset, y0_ + y_offset, xsize_, ysize_);
 }

 template <template <class> class P, typename V>
 V* Row(P<V>* image, size_t y) const {
   JXL_DASSERT(y + y0_ >= 0);
   return image->Row(y + y0_) + x0_;
 }

 template <template <class> class P, typename V>
 const V* Row(const P<V>* image, size_t y) const {
   JXL_DASSERT(y + y0_ >= 0);
   return image->Row(y + y0_) + x0_;
 }

 template <template <class> class MP, typename V>
 V* PlaneRow(MP<V>* image, const size_t c, size_t y) const {
   JXL_DASSERT(y + y0_ >= 0);
   return image->PlaneRow(c, y + y0_) + x0_;
 }

 template <template <class> class P, typename V>
 const V* ConstRow(const P<V>& image, size_t y) const {
   JXL_DASSERT(y + y0_ >= 0);
   return image.ConstRow(y + y0_) + x0_;
 }

 template <template <class> class MP, typename V>
 const V* ConstPlaneRow(const MP<V>& image, size_t c, size_t y) const {
   JXL_DASSERT(y + y0_ >= 0);
   return image.ConstPlaneRow(c, y + y0_) + x0_;
 }

 bool IsInside(const RectT& other) const {
   return x0_ >= other.x0() && x1() <= other.x1() && y0_ >= other.y0() &&
          y1() <= other.y1();
 }

 bool IsSame(const RectT& other) const {
   return x0_ == other.x0_ && xsize_ == other.xsize_ && y0_ == other.y0_ &&
          ysize_ <= other.ysize_;
 }

 // Returns true if this Rect fully resides in the given image. ImageT could be
 // Plane<T> or Image3<T>; however if ImageT is Rect, results are nonsensical.
 template <class ImageT>
 bool IsInside(const ImageT& image) const {
   return IsInside(RectT(image));
 }

 T x0() const { return x0_; }
 T y0() const { return y0_; }
 size_t xsize() const { return xsize_; }
 size_t ysize() const { return ysize_; }
 T x1() const { return x0_ + xsize_; }
 T y1() const { return y0_ + ysize_; }

 RectT<T> ShiftLeft(size_t shiftx, size_t shifty) const {
   return RectT<T>(x0_ * (1 << shiftx), y0_ * (1 << shifty), xsize_ << shiftx,
                   ysize_ << shifty);
 }
 RectT<T> ShiftLeft(size_t shift) const { return ShiftLeft(shift, shift); }

 // Requires x0(), y0() to be multiples of 1<<shiftx, 1<<shifty.
 StatusOr<RectT<T>> CeilShiftRight(std::pair<size_t, size_t> shift) const {
   size_t shiftx = shift.first;
   size_t shifty = shift.second;
   JXL_ENSURE((x0_ % (1 << shiftx) == 0) && (y0_ % (1 << shifty) == 0));
   return RectT<T>(x0_ / (1 << shiftx), y0_ / (1 << shifty),
                   DivCeil(xsize_, T{1} << shiftx),
                   DivCeil(ysize_, T{1} << shifty));
 }

 RectT<T> Extend(T border, RectT<T> parent) const {
   T new_x0 = x0() > parent.x0() + border ? x0() - border : parent.x0();
   T new_y0 = y0() > parent.y0() + border ? y0() - border : parent.y0();
   T new_x1 = x1() + border > parent.x1() ? parent.x1() : x1() + border;
   T new_y1 = y1() + border > parent.y1() ? parent.y1() : y1() + border;
   return RectT<T>(new_x0, new_y0, new_x1 - new_x0, new_y1 - new_y0);
 }

 template <typename U>
 RectT<U> As() const {
   return RectT<U>(static_cast<U>(x0_), static_cast<U>(y0_),
                   static_cast<U>(xsize_), static_cast<U>(ysize_));
 }

private:
 // Returns size_max, or whatever is left in [begin, end).
 static constexpr size_t ClampedSize(T begin, size_t size_max, T end) {
   return (static_cast<T>(begin + size_max) <= end)
              ? size_max
              : (end > begin ? end - begin : 0);
 }

 T x0_;
 T y0_;

 size_t xsize_;
 size_t ysize_;
};

template <typename T>
std::string Description(RectT<T> r) {
 std::ostringstream os;
 os << "[" << r.x0() << ".." << r.x1() << ")x"
    << "[" << r.y0() << ".." << r.y1() << ")";
 return os.str();
}

using Rect = RectT<size_t>;

}  // namespace jxl

#endif  // LIB_JXL_BASE_RECT_H_