Re: "changed" signal

[muppet <scott asofyet org>]

On Mar 5, 2005, at 9:22 AM, Ari Jolma wrote:

> my $h = new_with_range Gtk2::HScale (0,10,1);
> $h->signal_connect("changed" => sub {print "changed\n" });
> $h->signal_connect("value-changed" => sub {print"value changed\n"} );
>
> this gives a warning: signal "changed" is invalid

Indeed, because "changed" is one of Gtk2::Adjustment's signals, not a  
Gtk2::Scale's.

Also, the "changed" signal means that the properties of the adjustment  
have changed -- e.g. the max value, the min value, the step increment.   
The *value-changed* signal of Gtk2::Adjustment is what gets fired with  
the actual current value changes.

http://developer.gnome.org/doc/API/2.0/gtk/ 
GtkAdjustment.html#GtkAdjustment-changed


> my $h = new_with_range Gtk2::HScale (0,10,1);
> $h->get_adjustment->signal_connect("changed" => sub {print "changed\n"  
> });
> $h->signal_connect("value-changed" => sub {print"value changed\n"} );
>
> this does not give a warning but the subroutine is never called, even  
> though I resize the scale (it is in a window)

I get "value-changed" called on every move of the slider.

  #!/usr/bin/perl -w
  use strict;
  use Glib ':constants';
  use Gtk2 -init;
  my $window = Gtk2::Window->new;
  $window->signal_connect (destroy => sub {Gtk2->main_quit});
  my $h = new_with_range Gtk2::HScale (0, 10, 1);
  $h->signal_connect (value_changed => sub {
           print "value-changed : now ".$h->get_value."\n"
  });
  $window->add ($h);
  $window->show_all;
  Gtk2->main;

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