use Tk; my @TAGS; my $canvas_width = 600; my $canvas_height = 600; my $mw = new MainWindow; my $top = $mw->Frame()->pack(-side=>'top'); $canvas=$top->Canvas( -width=>$canvas_width, -height=>$canvas_height, )->pack(-side=>'left'); my $size = 410; my $entry = $top->Entry(-textvariable=>\$size)->pack(-side=>'top'); my $button = $top->Button(-text=>"go",-command=>\&go)->pack( -side=>'top'); $mw->Tk::bind('', [\&wheel,Ev('D')]); $canvas->Tk::bind( "