react-native/ReactCommon/fabric/graphics/Geometry.h

// Copyright (c) Facebook, Inc. and its affiliates.

// This source code is licensed under the MIT license found in the
// LICENSE file in the root directory of this source tree.

#pragma once

#include <algorithm>
#include <functional>
#include <tuple>

#include <fabric/graphics/Float.h>

namespace facebook {
namespace react {

/*
 * Point
 */
struct Point {
  Float x {0};
  Float y {0};

  Point &operator+=(const Point &point) {
    x += point.x;
    y += point.y;
    return *this;
  }

  Point &operator*=(const Point &point) {
    x *= point.x;
    y *= point.y;
    return *this;
  }

  friend Point operator+(Point lhs, const Point &rhs) {
    return lhs += rhs;
  }

  bool operator==(const Point &rhs) const {
    return
      std::tie(this->x, this->y) ==
      std::tie(rhs.x, rhs.y);
  }

  bool operator!=(const Point &rhs) const {
    return !(*this == rhs);
  }
};

/*
 * Size
 */
struct Size {
  Float width {0};
  Float height {0};

  Size &operator+=(const Point &point) {
    width += point.x;
    height += point.y;
    return *this;
  }

  Size &operator*=(const Point &point) {
    width *= point.x;
    height *= point.y;
    return *this;
  }

  bool operator==(const Size &rhs) const {
    return
      std::tie(this->width, this->height) ==
      std::tie(rhs.width, rhs.height);
  }

  bool operator!=(const Size &rhs) const {
    return !(*this == rhs);
  }
};

/*
 * Rect: Point and Size
 */
struct Rect {
  Point origin {0, 0};
  Size size {0, 0};

  bool operator==(const Rect &rhs) const {
    return
      std::tie(this->origin, this->size) ==
      std::tie(rhs.origin, rhs.size);
  }

  bool operator!=(const Rect &rhs) const {
    return !(*this == rhs);
  }

  Float getMaxX() const { return size.width > 0 ? origin.x + size.width : origin.x; }
  Float getMaxY() const { return size.height > 0 ? origin.y + size.height : origin.y; }
  Float getMinX() const { return size.width >= 0 ? origin.x : origin.x + size.width; }
  Float getMinY() const { return size.height >= 0 ? origin.y : origin.y + size.height; }

  void unionInPlace(const Rect &rect) {
    auto x1 = std::min(getMinX(), rect.getMinX());
    auto y1 = std::min(getMinY(), rect.getMinY());
    auto x2 = std::max(getMaxX(), rect.getMaxX());
    auto y2 = std::max(getMaxY(), rect.getMaxY());
    origin = {x1, y1};
    size = {x2 - x1, y2 - y1};
  }
};

/*
 * Generic data structure describes some values associated with *edges*
 * of a rectangle.
 */
template <typename T>
struct RectangleEdges {
  T left {};
  T top {};
  T right {};
  T bottom {};

  bool operator==(const RectangleEdges<T> &rhs) const {
    return
      std::tie(this->left, this->top, this->right, this->bottom) ==
      std::tie(rhs.left, rhs.top, rhs.right, rhs.bottom);
  }

  bool operator!=(const RectangleEdges<T> &rhs) const {
    return !(*this == rhs);
  }

  bool isUniform() const {
    return left == top &&
      left == right &&
      left == bottom;
  }
};

/*
 * Generic data structure describes some values associated with *corners*
 * of a rectangle.
 */
template <typename T>
struct RectangleCorners {
  T topLeft {};
  T topRight {};
  T bottomLeft {};
  T bottomRight {};

  bool operator==(const RectangleCorners<T> &rhs) const {
    return
      std::tie(this->topLeft, this->topRight, this->bottomLeft, this->bottomRight) ==
      std::tie(rhs.topLeft, rhs.topRight, rhs.bottomLeft, rhs.bottomRight);
  }

  bool operator!=(const RectangleCorners<T> &rhs) const {
    return !(*this == rhs);
  }

  bool isUniform() const {
    return topLeft == topRight &&
      topLeft == bottomLeft &&
      topLeft == bottomRight;
  }
};

/*
 * EdgeInsets
 */
using EdgeInsets = RectangleEdges<Float>;

/*
 * CornerInsets
 */
using CornerInsets = RectangleCorners<Float>;

} // namespace react
} // namespace facebook

namespace std {
  template <>
  struct hash<facebook::react::Point> {
    size_t operator()(const facebook::react::Point &point) const {
      return
        hash<decltype(point.x)>{}(point.x) +
        hash<decltype(point.y)>{}(point.y);
    }
  };

  template <>
  struct hash<facebook::react::Size> {
    size_t operator()(const facebook::react::Size &size) const {
      return
        hash<decltype(size.width)>{}(size.width) +
        hash<decltype(size.height)>{}(size.height);
    }
  };

  template <>
  struct hash<facebook::react::Rect> {
    size_t operator()(const facebook::react::Rect &rect) const {
      return
        hash<decltype(rect.origin)>{}(rect.origin) +
        hash<decltype(rect.size)>{}(rect.size);
    }
  };

  template <typename T>
  struct hash<facebook::react::RectangleEdges<T>> {
    size_t operator()(const facebook::react::RectangleEdges<T> &edges) const {
      return
        hash<decltype(edges.left)>{}(edges.left) +
        hash<decltype(edges.right)>{}(edges.right) +
        hash<decltype(edges.top)>{}(edges.top) +
        hash<decltype(edges.bottom)>{}(edges.bottom);
    }
  };

  template <typename T>
  struct hash<facebook::react::RectangleCorners<T>> {
    size_t operator()(const facebook::react::RectangleCorners<T> &corners) const {
      return
        hash<decltype(corners.topLeft)>{}(corners.topLeft) +
        hash<decltype(corners.bottomLeft)>{}(corners.bottomLeft) +
        hash<decltype(corners.topRight)>{}(corners.topRight) +
        hash<decltype(corners.bottomRight)>{}(corners.bottomRight);
    }
  };

} // namespace std