Thread: [Gtk2-perl-bugs] [Bug 567688] New: signal_chain_from_overridden in size_request class closure

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  gnome-perl | Gtk2 | Ver: unspecified
           Summary: signal_chain_from_overridden in size_request class
                    closure
           Product: gnome-perl
           Version: unspecified
          Platform: Other
        OS/Version: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: Normal
         Component: Gtk2
        AssignedTo: gtk...@li...
        ReportedBy: us...@zi...
         QAContact: gtk...@li...
     GNOME version: Unspecified
   GNOME milestone: Unspecified

As noted in the Gtk2::Widget signals pod, chaining up to a superclass
size_request doesn't fill in any data.

The program below prints (among other things)

    after chain: 0x0

where I hoped the signal_chain_from_overridden would go to the Gtk2::Label
size_request handler and get a desired size from it.  (You can see the desired
size by changing $foo to a plain Gtk2::Label per the commented out line in
main).

Chasing it down, I believe somewhere deep in signal_chain_from_overridden the
Gtk2::Requisition supplied in the perl call is copied, so the pointer going to
the g_signal_chain_from_overridden (in a GValue) is not the original and so the
width/height stored in it by GtkLabel are never seen.

It made me wonder if most of the time a boxed object should be copied or not
copied when passed to a C func.  But certainly in this case it shouldn't, since
it's a kind of output location.

package Foo;
use strict;
use warnings;

use Gtk2;
use Glib::Object::Subclass
  'Gtk2::Label',
  signals => { size_request => \&_do_size_request };

sub _do_size_request {
  my ($self, $req) = @_;
  print "this is Foo::_do_size_request\n";
  print "text is '",$self->get_text,"'\n";
  print "before chain: ",$req->width,"x",$req->height,"\n";
  Glib::Object::signal_chain_from_overridden ($self, $req);
  print "after chain: ",$req->width,"x",$req->height,"\n";
}

package main;
use strict;
use warnings;
use Gtk2 '-init';

my $window = Gtk2::Window->new('toplevel');
my $foo = Foo->new();
#
# my $foo = Gtk2::Label->new();
#
$foo->set_text ('hello world');
$window->add ($foo);
$window->show_all;

my $req = $foo->size_request();
print "main: foo size ",$req->width,"x",$req->height,"\n";

Gtk2->main();

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Thread: [Gtk2-perl-bugs] [Bug 567688] New: signal_chain_from_overridden in size_request class closure

gtk2-perl-bugs