convert_RGA_HSV

function convert_RGA_HSV ($colour) {
    $r = substr($colour,1,2);
    $g = substr($colour,3,2);
    $b = substr($colour,5,2);

    $r = $r/255;
    $g = $g/255;
    $b = $b/255;

    $h = 0;
    $s = 0;
    $v = 0;

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

    $r = $max-$min;
    $v = $max;

    if($r == 0){
        $h = 0;
        $s = 0;
    }
    else {
    $s = $r / $max;

    $hr = ((($max - $r) / 6) + ($r / 2)) / $r;
    $hg = ((($max - $g) / 6) + ($r / 2)) / $r;
    $hb = ((($max - $b) / 6) + ($r / 2)) / $r;

    if ($r == $max) $h = $hb - $hg;
    else if($g == $max) $h = (1/3) + $hr - $hb;
    else if ($b == $max) $h = (2/3) + $hg - $hr;

    if ($h < 0)$h += 1;
    if ($h > 1)$h -= 1;
    }
    return array($h, $s, $v);
}