Gtk.Widget::map-event

function callback(widget, event:Gdk.EventAny, ):Boolean;

The ::map-event signal will be emitted when the @widget's window is mapped. A window is mapped when it becomes visible on the screen.

To receive this signal, the Gdk.Window associated to the widget needs to enable the #GDK_STRUCTURE_MASK mask. GDK will enable this mask automatically for all new windows.

widget: instance of Gtk.Widget that is emitting the signal
event: the Gdk.EventAny which triggered this signal.
Returns: true to stop other handlers from being invoked for the event. false to propagate the event further.