Cleaning up my web space I found an old code to convert HSL triplets (Hue Saturation Lightness) to RGB (Red Blue Green). I think the code comes from the Gimp source code and was ported to Perl, but it’s so simple I think you can port easily everywhere.
So, why do you need to convert HSL to RGB? HSL values are more human understandable, so there a good choice for a color picket or something similar. But most graphic application require RGB values which are mostly used by computers.
And here is the code:
hsl_to_rgb($h, $s, $l); # Values in 0-255 range
sub hsl_to_rgb {
my $h = $_[0]/255;
my $s = $_[1]/255;
my $l = $_[2]/255;
my $r, $g, $b;
if ($h<1/6) {
$r = 1; $g = 6*$h; $b = 0;
$g = $g*$s + 1 - $s; $b = $b*$s + 1 - $s;
$r = $r*$l; $g = $g*$l; $b = $b*$l;
} elsif ($h<1/3) {
$r = 1-6*($h - 1/6); $g = 1; $b = 0;
$r = $r*$s + 1 - $s; $b = $b*$s + 1 - $s;
$r = $r*$l; $g = $g*$l; $b = $b*$l;
} elsif ($h<1/2) {
$r = 0; $g = 1; $b = 6*($h - 1/3);
$r = $r*$s + 1 - $s; $b = $b*$s + 1 - $s;
$r = $r*$l; $g = $g*$l; $b = $b*$l;
} elsif ($h<2/3) {
$r = 0; $g = 1-6*($h - 1/2); $b = 1;
$r = $r*$s + 1 - $s; $g = $g*$s + 1 - $s;
$r = $r*$l; $g = $g*$l; $b = $b*$l;
} elsif ($h<5/6) {
$r = 6*($h - 2/3); $g = 0; $b = 1;
$r = $r*$s + 1 - $s; $g = $g*$s + 1 - $s;
$r = $r*$l; $g = $g*$l; $b = $b*$l;
} else {
$r = 1; $g = 0; $b = 1-6*($h - 5/6);
$g = $g*$s + 1 - $s; $b = $b*$s + 1 - $s;
$r = $r*$l; $g = $g*$l; $b = $b*$l;
}
$r = int $r * 255;
$g = int $g * 255;
$b = int $b * 255;
return {r => $r, g => $g, b => $b);
}
Enjoy!