Using PHP to find a color's complement

November 22nd::2006 People know a color's complement as being the color opposite it on the color wheel. When you add these two colors together, you get a shade of gray (including white or black). I use this to find the color complement in a function. I'd like to break this out into color triads and such. Try it out! 


<?php

    function getComplement($baseColor)
    {
        #break out into RGB format
        $r = hexdec(substr($baseColor, 0, 2));
        $g = hexdec(substr($baseColor, 2, 2));
        $b = hexdec(substr($baseColor, 4, 2)); 


        # sprintf is used to keep leading zeros
        $complement  = sprintf("%02s", dechex(255- $r));
        $complement .= sprintf("%02s", dechex(255- $g));
        $complement .= sprintf("%02s", dechex(255- $b));


        return $complement;
    }

    $complement = getComplement($_GET['color']);

?>