cairo:region-xor-rectangle (region x y width height)

region -- a cairo:region-t instance
x -- an integer for the x coordinate
y -- an integer for the y coordinate
width -- an integer for the width of the rectangle
height -- an integer for the height of the rectangle

The passed in cairo:region-t instance with the result or nil if an error occured.

Computes the exclusive difference of region with rectangle and places the result in region. That is, region will be set to contain all areas that are either in region or in rectangle, but not in both.