rect.h

// Aseprite Gfx Library
// Copyright (C) 2001-2016 David Capello
//
// This file is released under the terms of the MIT license.
// Read LICENSE.txt for more information.

#ifndef GFX_RECT_H_INCLUDED
#define GFX_RECT_H_INCLUDED
#pragma once

namespace gfx {

template<typename T> class PointT;
template<typename T> class SizeT;
template<typename T> class BorderT;

// A rectangle.
template<typename T>
class RectT
{
public:
  T x, y, w, h;

  T x2() const { return x+w; }
  T y2() const { return y+h; }

  // Creates a new empty rectangle with the origin in 0,0.
  RectT() : x(0), y(0), w(0), h(0) {
  }

  // Creates a new rectangle with the specified size with the origin in 0,0.
  RectT(const T& w, const T& h) :
    x(0), y(0),
    w(w), h(h) {
  }

  // Creates a new rectangle with the specified size with the origin in 0,0.
  explicit RectT(const SizeT<T>& size) :
    x(0), y(0),
    w(size.w), h(size.h) {
  }

  RectT(const RectT<T>& rect) :
    x(rect.x), y(rect.y),
    w(rect.w), h(rect.h) {
  }

  template<typename T2>
  RectT(const RectT<T2>& rect) :
    x(static_cast<T>(rect.x)), y(static_cast<T>(rect.y)),
    w(static_cast<T>(rect.w)), h(static_cast<T>(rect.h)) {
  }

  RectT(const PointT<T>& point, const SizeT<T>& size) :
    x(point.x), y(point.y),
    w(size.w), h(size.h) {
  }

  // Creates a new rectangle with the origin in point1 and size
  // equal to point2-point1.
  //
  // If a coordinate of point1 is greater than point2, the coordinates
  // are swapped. The resulting rectangle will be:
  //
  // x = min(point1.x, point2.x)
  // y = min(point1.y, point2.y)
  // w = max(point1.x, point2.x) - x
  // h = max(point1.x, point2.x) - y
  //
  // See that point2 isn't included in the rectangle, it's like the
  // point returned by point2() member function.
  RectT(const PointT<T>& point1, const PointT<T>& point2) {
    PointT<T> leftTop = point1;
    PointT<T> rightBottom = point2;
    T t;

    if (leftTop.x > rightBottom.x) {
      t = leftTop.x;
      leftTop.x = rightBottom.x;
      rightBottom.x = t;
    }

    if (leftTop.y > rightBottom.y) {
      t = leftTop.y;
      leftTop.y = rightBottom.y;
      rightBottom.y = t;
    }

    this->x = leftTop.x;
    this->y = leftTop.y;
    this->w = rightBottom.x - leftTop.x;
    this->h = rightBottom.y - leftTop.y;
  }

  RectT(const T& x, const T& y, const T& w, const T& h) : x(x), y(y), w(w), h(h) {
  }

  // Verifies if the width and/or height of the rectangle are less or
  // equal than zero.
  bool isEmpty() const {
    return (w <= 0 || h <= 0);
  }

  // Returns the middle point of the rectangle (x+w/2, y+h/2).
  PointT<T> center() const {
    return PointT<T>(x+w/2, y+h/2);
  }

  // Returns the point in the upper-left corner (that is inside the
  // rectangle).
  PointT<T> origin() const {
    return PointT<T>(x, y);
  }

  // Returns point in the lower-right corner that is outside the
  // rectangle (x+w, y+h).
  PointT<T> point2() const {
    return PointT<T>(x+w, y+h);
  }

  SizeT<T> size() const {
    return SizeT<T>(w, h);
  }

  RectT& setOrigin(const PointT<T>& pt) {
    x = pt.x;
    y = pt.y;
    return *this;
  }

  RectT& setSize(const SizeT<T>& sz) {
    w = sz.w;
    h = sz.h;
    return *this;
  }

  // Moves the rectangle origin in the specified delta.
  RectT& offset(const T& dx, const T& dy) {
    x += dx;
    y += dy;
    return *this;
  }

  RectT& offset(const PointT<T>& delta) {
    x += delta.x;
    y += delta.y;
    return *this;
  }

  RectT& inflate(const T& delta) {
    w += delta;
    h += delta;
    return *this;
  }

  RectT& inflate(const T& dw, const T& dh) {
    w += dw;
    h += dh;
    return *this;
  }

  RectT& inflate(const SizeT<T>& delta) {
    w += delta.w;
    h += delta.h;
    return *this;
  }

  RectT& enlarge(const T& unit) {
    x -= unit;
    y -= unit;
    w += unit<<1;
    h += unit<<1;
    return *this;
  }

  RectT& enlarge(const BorderT<T>& br) {
    x -= br.left();
    y -= br.top();
    w += br.left() + br.right();
    h += br.top() + br.bottom();
    return *this;
  }

  RectT& shrink(const T& unit) {
    x += unit;
    y += unit;
    w -= unit<<1;
    h -= unit<<1;
    return *this;
  }

  RectT& shrink(const BorderT<T>& br) {
    x += br.left();
    y += br.top();
    w -= br.left() + br.right();
    h -= br.top() + br.bottom();
    return *this;
  }

  // Returns true if this rectangle encloses the pt point.
  bool contains(const PointT<T>& pt) const {
    return
      pt.x >= x && pt.x < x+w &&
      pt.y >= y && pt.y < y+h;
  }

  bool contains(const T& u, const T& v) const {
    return
      u >= x && u < x+w &&
      v >= y && v < y+h;
  }

  // Returns true if this rectangle entirely contains the rc rectangle.
  bool contains(const RectT& rc) const {
    if (isEmpty() || rc.isEmpty())
      return false;

    return
      rc.x >= x && rc.x+rc.w <= x+w &&
      rc.y >= y && rc.y+rc.h <= y+h;
  }

  // Returns true if the intersection between this rectangle with rc
  // rectangle is not empty.
  bool intersects(const RectT& rc) const {
    if (isEmpty() || rc.isEmpty())
      return false;

    return
      rc.x < x+w && rc.x+rc.w > x &&
      rc.y < y+h && rc.y+rc.h > y;
  }

  // Returns the union rectangle between this and rc rectangle.
  RectT createUnion(const RectT& rc) const {
    if (isEmpty())
      return rc;
    else if (rc.isEmpty())
      return *this;
    else
      return RectT(PointT<T>(x < rc.x ? x: rc.x,
                             y < rc.y ? y: rc.y),
                   PointT<T>(x+w > rc.x+rc.w ? x+w: rc.x+rc.w,
                             y+h > rc.y+rc.h ? y+h: rc.y+rc.h));
  }

  // Returns the intersection rectangle between this and rc rectangles.
  RectT createIntersection(const RectT& rc) const {
    if (intersects(rc))
      return RectT(PointT<T>(x > rc.x ? x: rc.x,
                             y > rc.y ? y: rc.y),
                   PointT<T>(x+w < rc.x+rc.w ? x+w: rc.x+rc.w,
                             y+h < rc.y+rc.h ? y+h: rc.y+rc.h));
    else
      return RectT();
  }

  const RectT& operator+=(const BorderT<T>& br) {
    enlarge(br);
    return *this;
  }

  const RectT& operator-=(const BorderT<T>& br) {
    shrink(br);
    return *this;
  }

  const RectT& operator|=(const RectT& rc) {
    return *this = createUnion(rc);
  }

  const RectT& operator&=(const RectT& rc) {
    return *this = createIntersection(rc);
  }

  RectT operator+(const BorderT<T>& br) const {
    return RectT(*this).enlarge(br);
  }

  RectT operator-(const BorderT<T>& br) const {
    return RectT(*this).shrink(br);
  }

  RectT operator|(const RectT& other) const {
    return createUnion(other);
  }

  RectT operator&(const RectT& other) const {
    return createIntersection(other);
  }

  bool operator==(const RectT& rc) const {
    return
      x == rc.x && w == rc.w &&
      y == rc.y && h == rc.h;
  }

  bool operator!=(const RectT& rc) const {
    return
      x != rc.x || w != rc.w ||
      y != rc.y || h != rc.h;
  }

};

typedef RectT<int> Rect;
typedef RectT<double> RectF;

} // namespace gfx

#endif