RGB To HSL

This algorithm converts RGB color model to HSL color model.

• C#
• VB.Net
• C
• C++
• PHP

									class HSL
{
	public $H;
	public $S;
	public $L;
}

class RGB
{
	public $R;
	public $G;
	public $B;
}

function RGBToHSL($rgb) {
	$hsl = new HSL();

	$r = ($rgb->R / 255.0);
	$g = ($rgb->G / 255.0);
	$b = ($rgb->B / 255.0);

	$min = min(min($r, $g), $b);
	$max = max(max($r, $g), $b);
	$delta = $max - $min;

	$hsl->L = ($max + $min) / 2;

	if ($delta == 0)
	{
		$hsl->H = 0;
		$hsl->S = 0.0;
	}
	else
	{
		$hsl->S = ($hsl->L <= 0.5) ? ($delta / ($max + $min)) : ($delta / (2 - $max - $min));

		if ($r == $max)
		{
			$hue = (($g - $b) / 6) / $delta;
		}
		else if ($g == $max)
		{
			$hue = (1.0 / 3) + (($b - $r) / 6) / $delta;
		}
		else
		{
			$hue = (2.0 / 3) + (($r - $g) / 6) / $delta;
		}

		if ($hue < 0)
			$hue += 1;
		if ($hue > 1)
			$hue -= 1;

		$hsl->H = (int)($hue * 360);
	}

	return $hsl;
}
								

Example

									$data = new RGB();
$data->R = 82;
$data->G = 0;
$data->B = 87;

$value = RGBToHSL($data);
								

Output

									H: 296
S: 1
L: 0.17058823529412