inline bool IsEmpty() const;
IsEmpty determines whether a rectangle is empty. The following expression is used to determine this result:
(x1 >= x2) || (y1 >= y2)
Note
This empty state only applies to normal rectangles. Normal rectangles that are not empty can be represented by the following expression:
(x2 > x1) && (y2 > y1)
A Boolean value of 1 (true) if the rectangle is empty and 0 (false) if it is not.