Rich Jenks Rich Jenks - 27 days ago 14
CSS Question

PHP function to convert HSL to RGB or Hex

Does anyone know a PHP function (for >5.3) which can convert an HSL color to either RGB or Hex? I've tried a dozen Google searches and none of the functions I have found work as expected.

It doesn't matter whether the function converts to RGB or hex because converting between those two is trivial. The inputs are HSL values for CSS (Hue: 0–360, Saturation: 0–100, Lightness: 0–100).

Edit: Specifying the input and output format would be a bonus :)

Answer

Taking the code from one of the answers in the link of Jim's comment (PHP HSV to RGB formula comprehension), we can compute it as follows:

<?php    
    $hue = 209;
    $sat = 75;
    $lum = 60;

    $hue /= 360;
    $sat /= 100;
    $lum /= 100;

    $result = ColorHSLToRGB($hue, $sat, $lum);
    var_dump($result); echo '<br>';
    printf("rgb = %d,%d,%d<br>", $result['r'], $result['g'], $result['b']);




function ColorHSLToRGB($h, $s, $l){

        $r = $l;
        $g = $l;
        $b = $l;
        $v = ($l <= 0.5) ? ($l * (1.0 + $s)) : ($l + $s - $l * $s);
        if ($v > 0){
              $m;
              $sv;
              $sextant;
              $fract;
              $vsf;
              $mid1;
              $mid2;

              $m = $l + $l - $v;
              $sv = ($v - $m ) / $v;
              $h *= 6.0;
              $sextant = floor($h);
              $fract = $h - $sextant;
              $vsf = $v * $sv * $fract;
              $mid1 = $m + $vsf;
              $mid2 = $v - $vsf;

              switch ($sextant)
              {
                    case 0:
                          $r = $v;
                          $g = $mid1;
                          $b = $m;
                          break;
                    case 1:
                          $r = $mid2;
                          $g = $v;
                          $b = $m;
                          break;
                    case 2:
                          $r = $m;
                          $g = $v;
                          $b = $mid1;
                          break;
                    case 3:
                          $r = $m;
                          $g = $mid2;
                          $b = $v;
                          break;
                    case 4:
                          $r = $mid1;
                          $g = $m;
                          $b = $v;
                          break;
                    case 5:
                          $r = $v;
                          $g = $m;
                          $b = $mid2;
                          break;
              }
        }
        return array('r' => $r * 255.0, 'g' => $g * 255.0, 'b' => $b * 255.0);
}
?>

Output:

array(3) { ["r"]=> float(76.5) ["g"]=> float(155.55) ["b"]=> float(229.5) } 
rgb = 76,155,229
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