Re: GtkButton, enter-notify signal, and GdkWindow

[Mike Massonnet <mmassonnet gmail com>]

Hi,

2010/11/24 Brian Tietz <sdbtietz yahoo com>:
> I am creating two widget subclasses, one which is a subclass of GtkContainer and one which is a subclass of 
> GtkButton.  Both need to receive the enter-notify signal.  I can successfully obtain the enter-notify 
> signal fot GtkButton in my_button_subclass_init:
>
>     g_gtk_button_mouse_enter_notify_event = widget_class->enter_notify_event;
>     widget_class->enter_notify_event = my_button_subclass_enter_notify_event;
>
> That function does get called, I do my thing, and then call the GtkButton class version.  When I try to do 
> the same thing for my GtkContainer subclass though, it doesn't happen.  I more or less understand this: my 
> GtkContainer subclass is GTK_NO_WINDOW, and according to the Gtk docs I need to put it inside of a 
> GtkEventBox.  Fair enough.  But I am studying gtkbutton.c so see how to do this right and to copy its 
> methodology, and it isn't creating GtkEventBox.  I found a clue in gtk_button_realize: it's calling 
> gdk_window_new, so it seems that GtkButton has its own GdkWindow, which would explain why it received 
> enter-notify events.  Fair enough.  Here's the weird part though.  I found that GtkButton has the 
> GTK_NO_WINDOW flag set!  Any help in understanding these behaviors and observations would be appreciated.

You need to call gtk_widget_add_events() on your widget and add the
event GDK_ENTER_NOTIFY_MASK.

  http://library.gnome.org/devel/gtk/stable/GtkWidget.html#gtk-widget-add-events
  http://library.gnome.org/devel/gdk/2.22/gdk-Events.html#GdkEventMask


HTH
Kind Regards
-- 
Mike