Function To Darken A Colour With PHP

Function To Darken A Colour With PHP

18th May 2008 - 2 minutes read time

The following function will reduce a hexadecimal colour string by a set value. It can take three and six digit colour values.

function ColourDarken($colour, $dif=20)
{
 $colour = str_replace('#','', $colour);
 $rgb = '';
 if (strlen($colour) != 6) {
  // reduce the default amount a little
  $dif = ($dif==20)?$dif/10:$dif;
  for ($x = 0; $x < 3; $x++) {
   $c = hexdec(substr($colour,(1*$x),1)) - $dif;
   $c = ($c < 0) ? 0 : dechex($c);
   $rgb .= $c;
  }
 } else {
  for ($x = 0; $x < 3; $x++) {
   $c = hexdec(substr($colour, (2*$x),2)) - $dif;
   $c = ($c < 0) ? 0 : dechex($c);
   $rgb .= (strlen($c) < 2) ? '0'.$c : $c;
  }
 }
 return '#'.$rgb;
}

Here are some examples of use.

echo ColourDarken('#123456'); // #002042
echo ColourDarken('#666'); // #444
echo ColourDarken('#ffffff'); // #ebebeb
echo ColourDarken('#ffffff',1); // #eeeeee
PHP

Comments

Good ;)

I used thank you ;)

Submitted by Anon on Fri, 01/06/2012 - 19:24

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