RedeyeVentures\GeoPattern\GeoPattern::rgbToHSL PHP Метод

    protected function rgbToHSL($r, $g, $b)
    {
        $r /= 255;
        $g /= 255;
        $b /= 255;
        $max = max($r, $g, $b);
        $min = min($r, $g, $b);
        $l = ($max + $min) / 2;
        if ($max == $min) {
            $h = $s = 0;
        } else {
            $d = $max - $min;
            $s = $l > 0.5 ? $d / (2 - $max - $min) : $d / ($max + $min);
            switch ($max) {
                case $r:
                    $h = ($g - $b) / $d + ($g < $b ? 6 : 0);
                    break;
                case $g:
                    $h = ($b - $r) / $d + 2;
                    break;
                case $b:
                    $h = ($r - $g) / $d + 4;
                    break;
            }
            $h /= 6;
        }
        $h = floor($h * 360);
        $s = floor($s * 100);
        $l = floor($l * 100);
        return ['h' => $h, 's' => $s, 'l' => $l];
    }