    # File lib/rubygame/rect.rb, line 581
            def union!(rect)
                    self.normalize!
        rleft, rtop = self.topleft
        rright, rbottom = self.bottomright
                    r2 = Rect.new_from_object(rect).normalize!

                    rleft = [rleft, r2.left].min
                    rtop = [rtop, r2.top].min
                    rright = [rright, r2.right].max
                    rbottom = [rbottom, r2.bottom].max

                    self[0,4] = rleft, rtop, rright - rleft, rbottom - rtop
                    return self
            end