Template class for 2D rectangles. More...

#include <opencv2/core/types.hpp>

Collaboration diagram for cv::Rect_< _Tp >:

Public Types
typedef _Tp	value_type

Public Member Functions
	Rect_ ()
	default constructor

	Rect_ (_Tp _x, _Tp _y, _Tp _width, _Tp _height)

	Rect_ (const Point_< _Tp > &org, const Size_< _Tp > &sz)

	Rect_ (const Point_< _Tp > &pt1, const Point_< _Tp > &pt2)

	Rect_ (const Rect_ &r)=default

	Rect_ (Rect_ &&r) CV_NOEXCEPT=default

_Tp	area () const
	area (width*height) of the rectangle

Point_< _Tp >	br () const
	the bottom-right corner

template<typename _Tp2 >
bool	contains (const Point_< _Tp2 > &pt) const
	checks whether the rectangle contains the point

bool	empty () const
	true if empty

template<typename _Tp2 >
	operator Rect_< _Tp2 > () const
	conversion to another data type

Rect_ &	operator= (const Rect_ &r)=default

Rect_ &	operator= (Rect_ &&r) CV_NOEXCEPT=default

Size_< _Tp >	size () const
	size (width, height) of the rectangle

Point_< _Tp >	tl () const
	the top-left corner

Public Attributes
_Tp	height
	height of the rectangle

_Tp	width
	width of the rectangle

_Tp	x
	x coordinate of the top-left corner

_Tp	y
	y coordinate of the top-left corner

Detailed Description

template<typename _Tp>
class cv::Rect_< _Tp >

Template class for 2D rectangles.

described by the following parameters:

Coordinates of the top-left corner. This is a default interpretation of Rect_::x and Rect_::y in OpenCV. Though, in your algorithms you may count x and y from the bottom-left corner.
Rectangle width and height.

OpenCV typically assumes that the top and left boundary of the rectangle are inclusive, while the right and bottom boundaries are not. For example, the method Rect_::contains returns true if

\[x \leq pt.x < x+width, y \leq pt.y < y+height\]

Virtually every loop over an image ROI in OpenCV (where ROI is specified by Rect_<int> ) is implemented as:

for(int y = roi.y; y < roi.y + roi.height; y++)
    for(int x = roi.x; x < roi.x + roi.width; x++)
    {
        // ...
    }

In addition to the class members, the following operations on rectangles are implemented:

\(\texttt{rect} = \texttt{rect} \pm \texttt{point}\) (shifting a rectangle by a certain offset)
\(\texttt{rect} = \texttt{rect} \pm \texttt{size}\) (expanding or shrinking a rectangle by a certain amount)
rect += point, rect -= point, rect += size, rect -= size (augmenting operations)
rect = rect1 & rect2 (rectangle intersection)
rect = rect1 | rect2 (minimum area rectangle containing rect1 and rect2 )
rect &= rect1, rect |= rect1 (and the corresponding augmenting operations)
rect == rect1, rect != rect1 (rectangle comparison)

This is an example how the partial ordering on rectangles can be established (rect1 \(\subseteq\) rect2):

template<typename _Tp> inline bool
operator <= (const Rect_<_Tp>& r1, const Rect_<_Tp>& r2)
{
    return (r1 & r2) == r1;
}

For your convenience, the Rect_<> alias is available: cv::Rect

Examples: samples/cpp/camshiftdemo.cpp, samples/cpp/facedetect.cpp, samples/cpp/falsecolor.cpp, samples/cpp/ffilldemo.cpp, samples/cpp/grabcut.cpp, samples/cpp/peopledetect.cpp, samples/cpp/stitching.cpp, samples/cpp/stitching_detailed.cpp, samples/cpp/train_HOG.cpp, and samples/dnn/object_detection.cpp.

Member Typedef Documentation

◆ value_type

template<typename _Tp >

_Tp cv::Rect_< _Tp >::value_type

Constructor & Destructor Documentation

◆ Rect_() [1/6]

template<typename _Tp >

cv::Rect_< _Tp >::Rect_ ( )

default constructor

◆ Rect_() [2/6]

template<typename _Tp >

cv::Rect_< _Tp >::Rect_	(	_Tp	_x,
		_Tp	_y,
		_Tp	_width,
		_Tp	_height )

◆ Rect_() [3/6]

template<typename _Tp >

cv::Rect_< _Tp >::Rect_ ( const Rect_< _Tp > & r )

default

◆ Rect_() [4/6]

template<typename _Tp >

cv::Rect_< _Tp >::Rect_ ( Rect_< _Tp > && r )

default

◆ Rect_() [5/6]

template<typename _Tp >

cv::Rect_< _Tp >::Rect_	(	const Point_< _Tp > &	org,
		const Size_< _Tp > &	sz )

◆ Rect_() [6/6]

template<typename _Tp >

cv::Rect_< _Tp >::Rect_	(	const Point_< _Tp > &	pt1,
		const Point_< _Tp > &	pt2 )

Member Function Documentation

◆ area()

template<typename _Tp >

_Tp cv::Rect_< _Tp >::area ( ) const

area (width*height) of the rectangle

Examples: samples/cpp/camshiftdemo.cpp.

◆ br()

template<typename _Tp >

Point_< _Tp > cv::Rect_< _Tp >::br ( ) const

the bottom-right corner

Examples: samples/cpp/peopledetect.cpp.

◆ contains()

template<typename _Tp >

template<typename _Tp2 >

bool cv::Rect_< _Tp >::contains ( const Point_< _Tp2 > & pt ) const

inline

checks whether the rectangle contains the point

Warning: After OpenCV 4.11.0, when calling Rect.contains() with cv::Point2f / cv::Point2d point, point should not convert/round to int.
Rect_<int> r(0,0,500,500); Point_<float> pt(250.0f, 499.9f);

r.contains(pt) returns false.(OpenCV 4.10.0 or before)

r.contains(pt) returns true. (OpenCV 4.11.0 or later)

cv::Point_
Template class for 2D points specified by its coordinates x and y.
Definition types.hpp:163