Determine the intersection area of ​​two rectangles

Question

I have two rectangles, each of which is defined by a set of four coordinates. I read how to see if they intersect, but how can I calculate the intersection area? Rectangles are not aligned along the axes.

Is there an OpenCV feature for this? I was told that there is, but I did not find it.

Answer 1

Treat your rectangles as common polygons and lay out the problem in two steps:

• calculate the intersection of two polygons, which itself is a polygon (or empty);
• calculate the area of ​​the resulting polygon.

Both issues have a lot of literature on the Internet.

I do not know anything about OpenCV, so I can not give any advice.

Answer 2

You can easily convert the Qt library code for this to use it with OpenCV.

Look for this feature:

QRect QRect::operator&(const QRect &r) const 

In qrect.cpp .