I have never used a Canvas (like most of the other Tk widgets, as a matter of fact) but from the few things I've read of it a doubt remains: how can I display a number in each single "little rectangle"? I'll have to dig...

The thing that is powerful, and a bit tricky to master, is the concept of tags. You can devise very intricate schemes with tags and hashes of objects. Here is the basic idea. The number is centered here, but I tagged it upper-left-corner, to show you that you can create multiple text objects in the rectangles and refer to them differently with tags, and raise. lower, configure to be hidden, etc.

Your problem will be to find a way to reference the text creation points with respect to the location of the various rectangles on the canvas. It can all be done, maybe using 'groups' or make them independent objects, and do something like "my $cell{1}{'obj} = new Cell(-x=>$x,-y=>$y) in some sort of double loop to make your grid. Then all your need to do is make text points in the object, (or even a plain hash will do), and you can get them with syntax like $cell{2}{upper_left}, etc. Or if OO, $cell{2}->upper_left

#!/usr/bin/perl
use Tk;
use strict;
my $w=20;
my $x=0;
my $y=0;

my %nums = (
   0 => ['black','yellow'],
   1 => ['yellow','black'],
   2 => ['white','green'],
   3 => ['green','white'],
   4 => ['grey','red'],
   5 => ['red','grey'],
   6 => ['blue','white'],
   7 => ['white','blue'],
   8 => ['orange','grey45'],
   9 => ['grey45','orange'],
);


my $mw=tkinit;
my $c = $mw->Canvas->pack;

for (0..9) {
 my $item=$c->createRectangle($x,$y,$x+20,$y+20,
             -fill=> ${$nums{$_}}[0],
             -tags => ['rect']
          );

my $text = $c->createText($x+10,$y+10,
           -anchor=>'center',
           -fill => ${$nums{$_}}[1],
           -text => $_,
           -tags => ['num','upper-left-corner']
          );

      $x+=20;
}

$mw->Button(
    -text    => "Hide Text",
    -command => sub {
            $c->lower('num','rect');
             })->pack;

$mw->Button(
    -text    => "Show Text",
    -command => sub {
            $c->raise('num','rect');
             })->pack;
MainLoop;
[download]

---

I'm not really a human, but I play one on earth. flash japh

zentara, thank you for your Tk pearls (or perls? :), I did hope you would give some advice and I was right - your technique seems really powerful!

As for the particular issue, my fear is that I'm going to create the same number of objects as before, if not more. In my original design, I create a Label for each of the tiny numbers, and defer the creation of the big number. In this case I still have to create a single Rectangle for each number (even if I can do some trick to defer the creation of the text). I fear that this will not improve my loading times much :/

Anyway, I'll give it a try and do some benchmarking - but probably this will be done in September ;)

Flavio
perl -ple'$_=reverse' <<<ti.xittelop@oivalf

Don't fool yourself.