CRect::SubtractRect
Makes the dimensions of the CRect equal to the subtraction of lpRectSrc2 from lpRectSrc1.
BOOL SubtractRect(
LPCRECT lpRectSrc1,
LPCRECT lpRectSrc2
) throw( );
Parameters
lpRectSrc1
Points to the RECT structure or CRect object from which a rectangle is to be subtracted.lpRectSrc2
Points to the RECT structure or CRect object that is to be subtracted from the rectangle pointed to by the lpRectSrc1 parameter.
Return Value
Nonzero if the function is successful; otherwise 0.
Remarks
The subtraction is the smallest rectangle that contains all of the points in lpRectScr1 that are not in the intersection of lpRectScr1 and lpRectScr2.
The rectangle specified by lpRectSrc1 will be unchanged if the rectangle specified by lpRectSrc2 doesn't completely overlap the rectangle specified by lpRectSrc1 in at least one of the x- or y-directions.
For example, if lpRectSrc1 were (10,10, 100,100) and lpRectSrc2 were (50,50, 150,150), the rectangle pointed to by lpRectSrc1 would be unchanged when the function returned. If lpRectSrc1 were (10,10, 100,100) and lpRectSrc2 were (50,10, 150,150), however, the rectangle pointed to by lpRectSrc1 would contain the coordinates (10,10, 50,100) when the function returned.
SubtractRect is not the same as operator - nor operator -=. Neither of these operators ever calls SubtractRect.
Nota
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
RECT rectOne;
RECT rectTwo;
rectOne.left = 10;
rectOne.top = 10;
rectOne.bottom = 100;
rectOne.right = 100;
rectTwo.left = 50;
rectTwo.top = 10;
rectTwo.bottom = 150;
rectTwo.right = 150;
CRect rectDiff;
rectDiff.SubtractRect(&rectOne, &rectTwo);
CRect rectResult(10, 10, 50, 100);
ASSERT(rectDiff == rectResult);
// works for CRect, too, since there is
// implicit CRect -> LPCRECT conversion
CRect rect1(10, 10, 100, 100);
CRect rect2(50, 10, 150, 150);
CRect rectOut;
rectOut.SubtractRect(rect1, rect2);
ASSERT(rectResult == rectOut);
Requirements
Header: atltypes.h