###############
# Error print #
###############

prompt$ perl gaugetest2
XS_Tk__Callback_Call error:Can't use an undefined value as an ARRAY reference at /usr/local/share/perl/5.12.4/Tk/Gauge.pm line 408.

XS_Tk__Callback_Call error:Can't use an undefined value as an ARRAY reference at /usr/local/share/perl/5.12.4/Tk/Gauge.pm line 408.

Tk::Error: Can't use an undefined value as an ARRAY reference at /usr/local/share/perl/5.12.4/Tk/Gauge.pm line 408.
 Tk::Gauge::maxradius at /usr/local/share/perl/5.12.4/Tk/Gauge.pm line 408
 Tk::Gauge::centerpoint at /usr/local/share/perl/5.12.4/Tk/Gauge.pm line 398
 Tk::Gauge::setvalue at /usr/local/share/perl/5.12.4/Tk/Gauge.pm line 321
 Tk::Gauge::tracew at /usr/local/share/perl/5.12.4/Tk/Gauge.pm line 383
 Tk::Trace::store at /usr/lib/perl5/Tk/Trace.pm line 94
 Tie::Watch::callback at /usr/lib/perl5/Tie/Watch.pm line 399
 Tie::Watch::Scalar::STORE at /usr/lib/perl5/Tie/Watch.pm line 453
 Tk::Widget::traceVdelete at /usr/lib/perl5/Tk/Trace.pm line 182
 Tk::Gauge::delete_traces at /usr/local/share/perl/5.12.4/Tk/Gauge.pm line 299
 Tk::Gauge::ConfigChanged at /usr/local/share/perl/5.12.4/Tk/Gauge.pm line 279
 Tk::After::once at /usr/lib/perl5/Tk/After.pm line 90
 [once,[{},after#11,idle,once,[ConfigChanged,{},{}]]]
 ("after" script)
Tk::Error: Can't use an undefined value as an ARRAY reference at /usr/local/share/perl/5.12.4/Tk/Gauge.pm line 408.
 Tk::Gauge::maxradius at /usr/local/share/perl/5.12.4/Tk/Gauge.pm line 408
 Tk::Gauge::centerpoint at /usr/local/share/perl/5.12.4/Tk/Gauge.pm line 398
 Tk::Gauge::setvalue at /usr/local/share/perl/5.12.4/Tk/Gauge.pm line 321
 Tk::Gauge::tracew at /usr/local/share/perl/5.12.4/Tk/Gauge.pm line 383
 Tk::Trace::store at /usr/lib/perl5/Tk/Trace.pm line 94
 Tie::Watch::callback at /usr/lib/perl5/Tie/Watch.pm line 399
 Tie::Watch::Scalar::STORE at /usr/lib/perl5/Tie/Watch.pm line 453
 Tk::Widget::traceVdelete at /usr/lib/perl5/Tk/Trace.pm line 182
 Tk::Gauge::delete_traces at /usr/local/share/perl/5.12.4/Tk/Gauge.pm line 299
 Tk::Gauge::ConfigChanged at /usr/local/share/perl/5.12.4/Tk/Gauge.pm line 279
 Tk::After::once at /usr/lib/perl5/Tk/After.pm line 90
 [once,[{},after#12,idle,once,[ConfigChanged,{},{}]]]
 ("after" script)
#######
# end #
#######

Perl code
#########
#!/usr/bin/perl -w
      
use Tk;
use Tk::Table;
use Tk::Gauge;
use strict;
use diagnostics;
        
my $mw = MainWindow->new;
$mw->geometry("75x75");
$mw->title("Gauge testing");

 my $button = $mw->Button(-text => "Null", -command => \&button3_sub)->pack(-anchor=>'center');

our ($alpha,$alphaone,$beta,$betaone,$mh,$output_text,$gaugevar,$cur);

sub button3_sub {
$mh= (35+(29-1)*6);
$cur=$mh;
my $hw = $mw -> Toplevel;
$hw ->geometry("650x450");
$hw ->title('Health Track (!!!WARNING:DO NOT EXIT THIS WINDOW UNTIL DONE)');
my $hf = $hw -> Frame(-background => 'white')->pack(-ipadx => 250, -fill => 'both', -expand =>'yes');
my $left_frame = $hf -> Frame (-background=>'white')->pack(-side=>'left', -fill => 'y');
my $right_frame = $hf->Frame(-background=>'white')->pack(-ipadx=>150, -fill =>'y', -anchor=>'n',-expand=>1);
         $betaone = $left_frame->Entry(-background => "green",)->pack(-anchor=>'nw');
        my $beta_button = $left_frame->Button(-text => "Alpha Null", -command => \&update_output)->pack(-anchor=>'nw');
         $alphaone = $left_frame->Entry(-background => "red",)->pack(-anchor=>'nw');
        my $alpha_button = $left_frame->Button(-text => "Alpha Null", -command => \&update_output)->pack(-anchor=>'nw');
 $output_text = $left_frame->Text(-height=>5,-width=>15)->pack(-expand=>0,);


my $gauge= $right_frame->Gauge(
     -background	   => 'white',
     -bands		   =>[
				{
				-piecolor => 'green',
				-minimum=> 50,
				-maximum=> 100,
				-tag=> 'Healthy',
				},
				{
				-piecolor => 'yellow',
				-minimum=> 25,
				-maximum=> 50,
				-tag=> 'Bloodied',
				},
				{
				-piecolor => 'red',
				-minimum=> 0,
				-maximum=> 25,
				-tag=> 'Critical',
				}
			     ],
     -bandplace => 'underticks',
     -bandstyle=> 'pieslice',
     -bandwidth=> 0,
     -caption => 'Current Value',
     -captioncolor=> 'black',
     -extent               => -180, 
     -from                 => 0,
     -hubcolor             => 'black',
     -huboutline	   => 'blue',
     -hubradius		   => 15,
     -majortickinterval    => 10,
     -majorticklabelplace  =>'outside',
     -finetickinterval     => 1,
     -minortickinterval    => 5,
     -margin		   =>40,
     -needles              => [
{
     -arrowshape => [ 12, 23, 6 ],
     -color      =>       'black',
     -command    =>         undef,
     -format     =>          '%d',
     -radius     =>           196,
     -showvalue  =>             1,
     -tag        =>            'null',
     -title      =>            'null',
     -titlecolor =>       'white',
     -titlefont  =>'Helvetica-12',
     -titleplace =>       'south',
     -variable   =>      \$gaugevar,
     -width      =>             5,
}
                              ] ,
     -start                => 180,
     -to                   => 100,
 )->pack(-fill=>'both',-expand=>1);

##my $gaugebutton1 = $left_frame ->Button(-text => "Update", -command => \&gaugebutton1_sub)->pack(-side=>'bottom'); #currently pointless. will leave in for possible diagnostics.

}
sub gaugebutton1_sub {
$gaugevar=($cur/$mh)*100;
}#above sub redundant(?) due to &update_output#
sub update_output {
  my $beta = $betaone->get();
  my $alpja = $alphaone->get();
  if ($alpha eq "") { $alpha = 0; }
  if ($beta eq "") { $beta = 0; }
$cur=$cur+$beta-$alpha;
  if ($cur gt $mh){$cur=$mh;}
  if ($cur lt 0){$cur=0;}
  my $output = "Current value:\n$cur";
  $output_text->delete('0.0', 'end');
  $output_text->insert("end", $output);
  $betaone->delete('0.0', 'end');
  $alphaone->delete('0.0', 'end');
$gaugevar=($cur/$mh)*100;
}

MainLoop;
###end