protected function is_point_in_bounding_box($pointxy, $xleftytop, $xrightybottom) {
        if ($pointxy[0] < $xleftytop[0]) {
            return false;
        } else if ($pointxy[0] > $xrightybottom[0]) {
            return false;
        } else if ($pointxy[1] < $xleftytop[1]) {
            return false;
        } else if ($pointxy[1] > $xrightybottom[1]) {
            return false;
        }
        return true;
    }