Learning OpenCV, 2nd Edition

Table 3-5. Overloaded operators that take objects of type cv::Rect

Operation

Example

Intersection of rectangles r1

and r2

cv::Rect r3 = r1 & r2;

r1 &= r2;

Minimum area rectangle

containing rectangles r1 and

r2

cv::Rect r3 = r1 | r2;

r1 |= r2;

Translate rectangle r by an

amount x

cv::Rect rx = r + v; // v is a cv::Point2i

r += v;

Enlarge a rectangle r by an

amount given by size s

cv::Rect rs = r + s; // s is a cv::Point2i

r += s;

Compare rectangles r1 and r2

for exact equality

bool eq = (r1 == r2);

Compare rectangles r1 and r2

for inequality

bool ne = (r1 != r2);

class cv::RotatedRect

The cv::RotatedRect class is one of the few classes in the C++ OpenCV interface that is not a

template underneath. It is a container, which holds a cv::Point2f called center, a cv::Size2f

called size, and one additional float called angle, with the latter representing the rotation of the

rectangle around center. One very important difference between cv::RotatedRect and cv::Rect

is the convention that a cv::RotatedRect is located in “space” relative to its center, while the

cv::Rect is located relative to its upper-left corner.

Table 3-6: Operations supported directly by class cv::RotatedRect

Operation

Example

Default constructors

cv::RotatedRect rr();

Copy constructor

cv::RotatedRect rr2( rr1 );

Construct from two corners

cv::RotatedRect( p1, p2 );

Value constructors; takes a

point, a size, and an angle

cv::RotatedRect rr( p, sz, theta ) ;

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