// 代表一个二维的矩形。
template<typename _Tp> class Rect_
{
public:
typedef _Tp value_type;
//! various constructors
Rect_();
Rect_(_Tp _x, _Tp _y, _Tp _width, _Tp _height);
Rect_(const Rect_& r);
Rect_(const CvRect& r);
Rect_(const Point_<_Tp>& org, const Size_<_Tp>& sz);
Rect_(const Point_<_Tp>& pt1, const Point_<_Tp>& pt2);
Rect_& operator = ( const Rect_& r );
//! the top-left corner
Point_<_Tp> tl() const;
//! the bottom-right corner
Point_<_Tp> br() const;
//! size (width, height) of the rectangle
Size_<_Tp> size() const;
//! area (width*height) of the rectangle
_Tp area() const;
//! conversion to another data type
template<typename _Tp2> operator Rect_<_Tp2>() const;
//! conversion to the old-style CvRect
operator CvRect() const;
//! checks whether the rectangle contains the point
bool contains(const Point_<_Tp>& pt) const;
_Tp x, y, width, height; //< the top-left corner, as well as width and height of the rectangle
};