Motion events in a DrawingArea

[Daniel Kasak <d j kasak dk gmail com>]

Hi all.

I'm trying to capture mouse events in a DrawingArea ( in Gtk3 ). I'm
adapting code at http://www.perlmonks.org/?node_id=583578 ... but when
I go:

$self->{drawing_area}->set_events(
    [ qw/   exposure-mask
            leave-notify-mask
            button-press-mask
            pointer-motion-mask
            pointer-motion-hint-mask
        /
    ]
);

 ... I get a warning:

Gtk-CRITICAL **: gtk_widget_set_events: assertion
'!_gtk_widget_get_realized (widget)' failed

I've tried putting this later on in the code when I guess the widget
*should* be realized, eg at the end of the render_graph() method which
I hook up thus:

$self->{drawing_area}->signal_connect( draw => sub {
$self->render_graph( @_ ) } );

 ... but it still gives the same error.

Next I try to connect to a signal handler anyway:

$self->{drawing_area}->signal_connect(
    'motion_notify_event'
  , sub { $self->handle_graph_mouse_move( @_ ) }
);

 ... but this handler never gets called.

I guess things have changed in Gtk3? I haven't been able to find an
updated demo, even in C. Any hints as to what I'm missing?

Dan