Indicates either pointer movement or a pointer button press or
           release. The pointer is now at (x-position, y-position),
           and the current state of buttons 1 to 8 are represented by
           bits 0 to 7 of button-mask respectively, 0 meaning up, 1
           meaning down (pressed).

def send_PointerEvent(self, x, y, buttonmask=0):
        """Indicates either pointer movement or a pointer button press or
           release. The pointer is now at (x-position, y-position),
           and the current state of buttons 1 to 8 are represented by
           bits 0 to 7 of button-mask respectively, 0 meaning up, 1
           meaning down (pressed).
        """
        self.sendMessage(struct.pack('!BBHH', 5, buttonmask, x, y))