use strict;
use warnings;
use diagnostics;
use Tk;

my $mw= MainWindow->new;

my $canvas= $mw->Canvas( -background => 'black',
             -width      => '100',
             -height     => '200',
                       )->pack;

$canvas->CanvasBind('<Motion>', \&print_coords);
&MainLoop;

sub print_coords
{
  my ($evt) = @_;
  my $e= $evt->XEvent;
  print $e->X,',',$e->Y,'  ',$e->x,',',$e->y,"\n";
}