public function addRectangle($x, $y, $width, $height, $invert = false)
    {
        $this->addPolygonCore(array(
            new Point($x, $y),
            new Point($x + $width, $y),
            new Point($x + $width, $y + $height),
            new Point($x, $y + $height),
        ), $invert);
    }