public function ascii($background = 'white', $colored = false,
        $foreground='red', $reverse = false, $size = 100)
    {
        $options = [
            'b' => $background,
            'c' => $colored ? 'true' : 'false',
            'f' => $foreground,
            'r' => $reverse ? 'true' : 'false',
            's' => $size
        ];

        // call TransformationMixin function
        $this->setTransformUrl('ascii', $options);

        return $this;
    }