private static function hueToRgb($m1, $m2, $hue)
    {
        $hue = ($hue < 0) ? $hue + 1 : (($hue > 1) ? $hue - 1 : $hue);
        if ($hue * 6 < 1) {
            return $m1 + ($m2 - $m1) * $hue * 6;
        }
        if ($hue * 2 < 1) {
            return $m2;
        }
        if ($hue * 3 < 2) {
            return $m1 + ($m2 - $m1) * (2 / 3 - $hue) * 6;
        }

        return $m1;
    }