#!/usr/bin/perl
use Gtk3 -init;
my $color = Gtk3::Gdk::Color::parse ($ARGV[0]);

my $complement = $color->copy;
$complement->red(255 - $complement->red);
$complement->green(255 - $complement->green);
$complement->blue(255 - $complement->blue);

printf "%s\n", $complement->to_string;