CreateRectRgn info Overview Group

The CreateRectRgn function creates a rectangular region.

HRGN CreateRectRgn(

int nLeftRect,	// x-coordinate of region’s upper-left corner
int nTopRect,	// y-coordinate of region’s upper-left corner
int nRightRect,	// x-coordinate of region’s lower-right corner
int nBottomRect	// y-coordinate of region’s lower-right corner
);

Parameters

nLeftRect: Specifies the x-coordinate of the upper-left corner of the region.
nTopRect: Specifies the y-coordinate of the upper-left corner of the region.
nRightRect: Specifies the x-coordinate of the lower-right corner of the region.
nBottomRect: Specifies the y-coordinate of the lower-right corner of the region.

If the function succeeds, the return value is the handle to the region.

If the function fails, the return value is NULL. To get extended error information, call GetLastError.

The region will be exclusive of the bottom and right edges.