Re: signals for canvas items

[Daniel Carrera <dcarrera math toronto edu>]

Thank you, that solved my problem.


For some reason the following doesn't work:

$rectangle = $Group->new($Group,"Gnome::CanvasRect",...);
$rectangle->signal_connect(...);


The signal_connect() produces the error:

Gtk-WARNING **: gtk_signal_connect(): could not find signal
"button_press" in the `GnomeCanvasEllipse' class ancestry


On the other hand, this works:
$rectangle = $Group->new($Group,"Gnome::CanvasRect",...,
                "signal::event" => [\&callback]
        );



Thanks again,
Daniel.


On Sun, 28 Apr 2002, Dov Grobgeld wrote:

> Hi Daniel,
>
> It should work. You can also do something like:
>
>     my $card_group =
>         Gnome::CanvasItem->new($W{root},
>                                "Gnome::CanvasGroup",
>                                "x", $cx-50,
>                                "y", $cy-50,
>                                "signal::event" => [\&move_card_cb]
>                               );
>
> (Taken from my abc-blocks program. See:
>
>     http://imagic.weizmann.ac.il/~dov/freesw/gtk/abc-blocks/abc-blocks.html
> ).
>
> In the callback you then have to test the type of the event and act
> according to it. The following is also from abc-blocks:
>
>     sub move_card_cb {
>         my($item, $event) = @_;
>
>         if ($event->{type} eq "button_press") {
>             if ($event->{button} eq '1') {
>                 $item->raise_to_top();
>                 $last_cx = $event->{x};
>                 $last_cy = $event->{y};
>
>                 $dragging++;
>             } elsif ($event->{button} eq '3') {
>                 $item->destroy();
>             }
>         }
>         elsif ($event->{type} eq "motion_notify") {
>             if ($dragging) {
>                 my $new_x = $event->{x};
>                 my $new_y = $event->{y};
>
>                 $item->move($new_x-$last_cx,$new_y-$last_cy);
>
>                 $last_cx = $new_x;
>                 $last_cy = $new_y;
>             }
>         }
>         elsif ($event->{type} eq "button_release") {
>             if ($event->{button} eq '1') {
>                 $dragging=0;
>             }
>         }
>     }
>
> I hope this helps.
>
> Regards,
> Dov
>
>
> On Sat, Apr 27, 2002 at 11:11:31PM -0400, Daniel Carrera wrote:
> > Hello,
> >
> > I wish to signal_connect() events for canvas items.  However that doesn't
> > work.  I have looked all over the documentation for something like this
> > but without success.
> >
> > What I would like to do is essentially:
> >
> > $rectangle = $group->new($Group,"Gnome::CanvasRect",...);
> >
> > $rectangle->signal_connect(...);
> >
> >
> > But this doesn't work.
> >
> >
> > Does anyone know how you would achieve this effect?
> >
> > Thanks a lot,
> > Daniel.
> >
> > _______________________________________________
> > gtk-perl-list mailing list
> > gtk-perl-list gnome org
> > http://mail.gnome.org/mailman/listinfo/gtk-perl-list
>
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