Convert Hex to HSL in PHP

hex_to_hsl.php

<?php
// To avoid the complexity, I use two separate functions.

function hexToHsl($hex) 
{
	// Convert hex to RGB
	if (strlen($hex) == 7) {
		$rgb = array_map('hexdec', str_split(ltrim($hex, '#'), 2));
	} else {
		$hex = '#' . implode( "", array_map( function($digit) {
			return str_repeat($digit, 2);   
		}, str_split(ltrim($hex, '#'), 1)) );
			$rgb = array_map('hexdec', str_split(ltrim($hex, '#'), 2));
	}

	// Convert RGB to HSL
	$hsl = rgbToHsl($rgb[0], $rgb[1], $rgb[2]);

	$hsl[0] = round($hsl[0], 1);
	$hsl[1] = round($hsl[1]) * 100 . "%";
	$hsl[2] = round($hsl[2] * 100) . "%";

	$output = 'hsl(' . implode( ", ", $hsl ) . ')';

		return $output;
       
}

function rgbToHsl($r, $g, $b) 
{
    // Normalize the RGB values
	$r /= 255;
	$g /= 255;
	$b /= 255;

	// Find the minimum and maximum RGB values
	$min = min($r, $g, $b);
	$max = max($r, $g, $b);

	// Calculate the hue
	if ($max == $min) {
		$h = 0;
	} else if ($max == $r) {
		$h = 60 * ($g - $b) / ($max - $min);
	} else if ($max == $g) {
		$h = 60 * ($b - $r) / ($max - $min) + 120;
	} else {
		$h = 60 * ($r - $g) / ($max - $min) + 240;
	}

	// Normalize the hue to be between 0 and 360
	if ($h < 0) {
		$h += 360;
	} else if ($h > 360) {
		$h -= 360;
	}

	// Calculate the saturation
	if ($max == 0) {
		$s = 0;
	} else {
		$s = ($max - $min) / $max;
	}

	// Calculate the lightness
	$l = ($max + $min) / 2;

	// Return the HSL values as an array
	return array($h, $s, $l);
    
}

echo hexToHsl( "#fff" ); // hsl(0, 0%, 100%)
echo hexToHsl( "#ffffff" ); // hsl(0, 0%, 100%)
echo hexToHsl( "#999" ); // hsl(0, 0%, 60%)