Frandajo has asked for the wisdom of the Perl Monks concerning the following question:

Dear Learned Ones,

I have a Tk application for an on-line, 3D, RP game that monitors the users avatar. One of the features is to set body scale. I would like a range from 0.01 to 9.99 but with 1.00 in the center...not crowded to the left 10%, where it would not make sense.

A logarithmic sort of Tk::Scale widget is needed. Surely I am not the first to desire such. I cannot imagine it does not exist. Yet I cannot find it.

I am currently making do with radiobuttons in discrete intervals. But this is really kind of clunky. Any directions toward where in Perl/Tk such a widget is to be found would be most appreciated.

Thanks bunches,

Fran

Replies are listed 'Best First'.
Re: A logarithmic Tk:Scale widget?
by graff (Chancellor) on Dec 09, 2007 at 20:21 UTC
    While you're waiting for the LogScale widget to show up on CPAN, you could experiment with offering the user a simple linear scale that controls the exponent to be applied to your avatar's body scale. Here's a stripped-down example of what the might look like: 
    #!/usr/bin/perl

use Tk;

$m=MainWindow->new(-title => "test");
$m->Button(-command => sub{exit(0)}, -text => "Bye")->pack;
my $scale_value_str = " current scale value =          ";
$m->Label(-textvariable => \$scale_value_str)->pack;
$m->Scale(-from => -2,
          -to => 2,
          -digits => 0,
          -resolution => -1,
          -command=>sub{$scale_value_str=sprintf " current scale = %8.
+3f ",10**$_[0]}
         )->pack;
MainLoop;

    [download]
    (updated to show the resulting scale value in the Tk window, rather than on stdout)
[reply]
[d/l]
Re: A logarithmic Tk:Scale widget?
by eserte (Deacon) on Dec 09, 2007 at 19:15 UTC
    I have a Tk::LogScale widget available. Shall I release it to CPAN?
[reply]
      Yes, please.
[reply]
        It's on the way... 
        The uploaded file

    Tk-LogScale-0.08.tar.gz

has entered CPAN as

  file: $CPAN/authors/id/S/SR/SREZIC/Tk-LogScale-0.08.tar.gz
  size: 4706 bytes
   md5: d779f93b739583495c4c784d0e6a209d

No action is required on your part
Request entered by: SREZIC (Slaven ReziÄ<87>)
Request entered on: Sun, 09 Dec 2007 20:31:58 GMT
Request completed:  Sun, 09 Dec 2007 20:32:33 GMT
[reply]
[reply]
Re: A logarithmic Tk:Scale widget?
by johngg (Canon) on Dec 09, 2007 at 18:16 UTC
    If I remember my schoolboy maths correctly, using a logarithmic scale with the range you give will result in the 1 being a little way towards the right, not in the centre. If you could modify your range to have a minimum of 0.1 rather than 0.05 you would be allright. I'm afraid I can't point you to a suitable widget, my Tk experience is not much beyond baby steps.

    Cheers,

    JohnGG

[reply]

      Yes, of course. Thank you so much for that, entirely correct observation. It remains wholly unhelpful, though, as you yourself did observe.

[reply]

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