use Tk;

$mw = Tk::MainWindow->new;
$can = $mw->Canvas(-width => 320, -height => 240)->pack();
$img = $mw->Photo(-width => 320, -height => 240, -palette => '256/256/256');
$img->blank;
$can->createImage(0, 0, -image => $img, -anchor => 'nw');
$img->put(RED, -to => (160, 120));
printf "%6.6X", $img->get(160, 120);

MainLoop();