perldoc Gnome2::Canvas::index

The Gnome2::Canvas is pretty basic. There are no such thing as tags( like in Tk). In Tk you can say something like "find all items with tag equal to whatever". In Gnome2::Canvas, you can make your own like

my @lines;
my $line2= Gnome2::Canvas::Item->new ($root,
                'Gnome2::Canvas::Line',  
                points => $points,                      
                fill_color => "red",
                width_units => 8.0,
                join_style => 'miter',
                );
$line2->{'tag'} = 'red', # maybe an array_ref for multiple tags?
push @lines, $line2; 

foreach my $line (@lines){ 
    if( $line->{'tag'} eq 'red' ){print "$line is red\n"} 
  }
[download]

Also see Gtk2 linked scrolled Canvases in table , saving a Gtk2 canvas which is bigger than the window, Gnome2::Canvas Scribble with Image, and Gtk2 Scrolling Text for some previous examples I've posted.