public static RECT Intersection(this RECT r1, RECT r2)
{
if (
// r2 has no points inside r1
(r1.InsideRect(r2.Left, r2.Top) == false &&
r1.InsideRect(r2.Left, r2.Bottom) == false &&
r1.InsideRect(r2.Right, r2.Top) == false &&
r1.InsideRect(r2.Right, r2.Bottom) == false) &&
// r1 has no points inside r2
(r2.InsideRect(r1.Left, r1.Top) == false &&
r2.InsideRect(r1.Left, r1.Bottom) == false &&
r2.InsideRect(r1.Right, r1.Top) == false &&
r2.InsideRect(r1.Right, r1.Bottom) == false)
)
{
return(new RECT(0, 0, 0, 0));
}
int left = Math.Max(r1.Left, r2.Left);
int top = Math.Max(r1.Top, r2.Top);
int right = Math.Min(r1.Right, r2.Right);
int bottom = Math.Min(r1.Bottom, r2.Bottom);
return(new RECT(left, top, right, bottom));
}