Makes the dimensions of CRect equal to the union of the two source rectangles.
BOOL UnionRect( 
   LPCRECT lpRect1, 
   LPCRECT lpRect2  
) throw( );
Parameters
- lpRect1 
 Points to a RECT or CRect that contains a source rectangle.
- lpRect2 
 Points to a RECT or CRect that contains a source rectangle.
Return Value
Nonzero if the union is not empty; 0 if the union is empty.
Remarks
The union is the smallest rectangle that contains both source rectangles.
Windows ignores the dimensions of an empty rectangle; that is, a rectangle that has no height or has no width.
备注
Both of the rectangles must be normalized or this function may fail. You can call NormalizeRect to normalize the rectangles before calling this function.
Example
CRect   rect1(100,   0, 200, 300);
CRect   rect2(0, 100, 300, 200);
CRect   rect3;
rect3.UnionRect(&rect1, &rect2);
CRect   rectResult(0, 0, 300, 300);
ASSERT(rectResult == rect3);   
Requirements
Header: atltypes.h