The UnionRect function creates the union of two rectangles. The union is the smallest rectangle that contains both source rectangles.
BOOL UnionRect(
LPRECT lprcDst, |
// address of structure for union |
CONST RECT *lprcSrc1, |
// address of structure with first rectangle |
CONST RECT *lprcSrc2 |
// address of structure with second rectangle |
); |
If the specified structure contains a nonempty rectangle, the return value is nonzero.
If the specified structure does not contain a nonempty rectangle, the return value is zero. To get extended error information, call GetLastError.
Windows ignores the dimensions of an empty rectangle ¾ that is, a rectangle in which all coordinates are set to zero, so that it has no height or no width.