The Tk::Gauge module generates all manner of gee-whiz analog graphs. Sadly, as far as I can tell, this is all it's doing at the moment. Repeated attemps to have it draw a needle on said graphs have failed. Having run several of the example scripts to no avail, I asked monks on the CB and bart confirmed my results.

What I've found is that if I try to graph my own needle, using Tk::Canvas (of which Tk::Gauge is a MegaWidget) methods, the line is drawn "behind" the Gauge. I expect this is what's happening to the lines the module draws as well.

So the question is, how do I bring lines I draw to the foreground, and is the Tk::Gauge module really broken?

Example code can be found in the link above, and below I will include my code that draws a line "behind" the gauge (based on the thermometer example).

#!/usr/local/bin/perl -w
use Tk;
use Tk::Gauge;
use strict;
use warnings;

my $mw = MainWindow->new;

our($temperature);

my $thermo = $mw->Gauge(
    -from                 => -20,
    -to                   => 40,
    -huboutline           => 'red',
    -majorticklabelskip   => [-20,40],
    -minortickinterval    => 5,
    -finetickinterval     => 1,
    -style                 => 'pieslice',
    -margin            => 20,
    -bandwidth           => 5,
    -bands           => [
                {
                   -minimum  => -20,
                   -maximum  => -5,
                   -arccolor => '#aa00aa',
                },
                {
                   -minimum  => -5,
                   -maximum  =>  5,
                   -arccolor => '#0000ff',
                },
                {
                   -minimum  =>  5,
                   -maximum  => 15,
                   -arccolor => '#00ff00',
                },
                {
                   -minimum  => 15,
                   -maximum  => 25,
                   -arccolor => '#ffff00',
                },
                {
                   -minimum  => 25,
                   -maximum  => 35,
                   -arccolor => '#ff8800',
                },
                {
                   -minimum  => 35,
                   -maximum  => 40,
                   -arccolor => '#ff0000',
                },
                  ],
     -needles              =>[
                      {
                  -arrowshape => [0,0,0],
                          -radius     => 60,
                          -variable   => \$temperature,
                  -color      => 'black',
                  -width      => 2,
                  -showvalue  => 1,
                  -format     => '%.1f C',
                      },
                 ],
)->pack;

$mw->after( 1000, sub{ $temperature = 18.2 } );

$thermo->createLine(0,0,200,200, -width => 5); # Line should go right 
+across gauge!

MainLoop;
[download]

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