Class cv::Rect_#

Template class for 2D rectangles. View details

#include <opencv2/core/types.hpp>

Collaboration diagram for cv::Rect_:

cv::Rect_< _Tp > Node1 cv::Rect_< _Tp >   + Rect_() + Rect_() + Rect_() + Rect_() + Rect_() + Rect_() + area() + br() + contains() + empty() + operator Rect_< _Tp2 >() + operator=() + operator=() + size() + tl() Node2 _Tp     Node2->Node1 +height +width +x +y

cv::Rect_< _Tp > Node1 cv::Rect_< _Tp >   + Rect_() + Rect_() + Rect_() + Rect_() + Rect_() + Rect_() + area() + br() + contains() + empty() + operator Rect_< _Tp2 >() + operator=() + operator=() + size() + tl() Node2 _Tp     Node2->Node1 +height +width +x +y

Detailed Description#

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

Member Typedef Documentation#

value_type#

typedef Tp cv::Rect::value_type

Constructor & Destructor Documentation#

Rect_()#

cv::Rect_::Rect_()

default constructor

Rect_()#

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

Rect_()#

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

Rect_()#

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

Rect_()#

cv::Rect_::Rect_(const Rect_ & r)

Rect_()#

cv::Rect_::Rect_(Rect_ && r)

Member Function Documentation#

area()#

Tp cv::Rect::area()

area (width*height) of the rectangle

br()#

Point_< Tp > cv::Rect::br()

the bottom-right corner

contains()#

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

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)

empty()#

bool cv::Rect_::empty()

true if empty

operator Rect_< _Tp2 >()#

template<typename _Tp2>
cv::Rect_::operator Rect_< _Tp2 >()

conversion to another data type

operator=()#

Rect_ & cv::Rect_::operator=(const Rect_ & r)

operator=()#

Rect_ & cv::Rect_::operator=(Rect_ && r)

size()#

Size_< Tp > cv::Rect::size()

size (width, height) of the rectangle

tl()#

Point_< Tp > cv::Rect::tl()

the top-left corner

Member Data Documentation#

height#

Tp cv::Rect::height

height of the rectangle

width#

Tp cv::Rect::width

width of the rectangle

x#

Tp cv::Rect::x

x coordinate of the top-left corner

y#

Tp cv::Rect::y

y coordinate of the top-left corner

Source file#

The documentation for this class was generated from the following file: