PHP snippet to convert RGB hex to HSL array, and HSL array to RGB hex

rgbToHSL.php

<?
function rgb2hsl( $rgb ) {
    $rgb = trim($rgb, '#');
    if( strlen($rgb) == 6)
        $rgb = str_split($rgb, 2);
    elseif( strlen($rgb) == 3)
        $rgb = array($rgb[0] . $rgb[0], $rgb[1] . $rgb[1], $rgb[2] . $rgb[2]);
    foreach($rgb as &$value)
	    $value = hexdec($value) / 255;

    $max = max( $rgb );
	$min = min( $rgb );

	$h;
	$s;
	$l = ( $max + $min ) / 2;
	$d = $max - $min;

    	if( $d == 0 ){
        	$h = $s = 0; // achromatic
    	} else {
        	$s = $d / ( 1 - abs( 2 * $l - 1 ) );

		switch( $max ){
	            case $rgb[0]:
	            	$h = 60 * fmod( ( ( $rgb[1] - $rgb[2] ) / $d ), 6 );
                        if ($rgb[2] > $rgb[1]) {
	                    $h += 360;
	                }
	                break;

	            case $rgb[1]:
	            	$h = 60 * ( ( $rgb[2] - $rgb[0] ) / $d + 2 );
	            	break;

	            case $rgb[2]:
	            	$h = 60 * ( ( $rgb[0] - $rgb[1] ) / $d + 4 );
	            	break;
	        }
	}

	// return array( round( $h, 3 ), round( $s, 3 ), round( $l, 3 ) );
	return array( $h, $s, $l );
}

function hsl2rgb( $h, $s, $l ){
    $r;
    $g;
    $b;

	$c = ( 1 - abs( 2 * $l - 1 ) ) * $s;
	$x = $c * ( 1 - abs( fmod( ( $h / 60 ), 2 ) - 1 ) );
	$m = $l - ( $c / 2 );

	if ( $h < 60 ) {
		$r = $c;
		$g = $x;
		$b = 0;
	} else if ( $h < 120 ) {
		$r = $x;
		$g = $c;
		$b = 0;
	} else if ( $h < 180 ) {
		$r = 0;
		$g = $c;
		$b = $x;
	} else if ( $h < 240 ) {
		$r = 0;
		$g = $x;
		$b = $c;
	} else if ( $h < 300 ) {
		$r = $x;
		$g = 0;
		$b = $c;
	} else {
		$r = $c;
		$g = 0;
		$b = $x;
	}

	$r = str_pad(dechex(round(( $r + $m ) * 255)), 2, '0', STR_PAD_LEFT) ;
	$g = str_pad(dechex(round(( $g + $m ) * 255)), 2, '0', STR_PAD_LEFT) ;
	$b = str_pad(dechex(round(( $b + $m  ) * 255)), 2, '0', STR_PAD_LEFT) ;

    return $r . $g . $b;
}
?>