On Sat, 2008-01-12 at 10:02 -0500, JLM wrote: > Some widget event handler functions return a boolean value. > on_expose_event is one. I think the return value is supposed to tell the > caller whether this widget handled the event or not.
Yes: http://www.gtkmm.org/docs/gtkmm-2.4/docs/tutorial/html/sec-xeventsignals.html > What exactly does it mean to handle the event? It means that no further signal handler will be asked to handle the event too. > For example, I have an on_expose_event function set up for my widget > that is subclassed from DrawingArea. When overeriding, remember also to call the base class's implementation. Sometimes it does something useful. > It only does something if the > widget is realized, so I put everything in an if(is_realized()) { ... } > block. So should I return false if the widget is not realized when this > function is called? Or is the widget considered to handle the event, but > it just happens to not do anything? > > Are there any rules of thumb for when to return true versus false in > these cases? I have often wondered the same thing in similar situations. I don't think I have a general answer, but maybe someone else does. I am generally not a fan of these signals or this technique because I think it requires you to have a knowledge of what the default implementation is. But that would be the same with the more-traditional C++ technique of override-and-sometimes-call-the-base-handler. -- [EMAIL PROTECTED] www.murrayc.com www.openismus.com _______________________________________________ gtkmm-list mailing list [email protected] http://mail.gnome.org/mailman/listinfo/gtkmm-list
