From: Olivier Andrieu <andrieu at ijm.jussieu.fr>
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Message-ID: <16331.8738.199661.466059 at akasha.ijm.jussieu.fr>
Date: Mon, 1 Dec 2003 12:12:34 +0100
To: Jacques Garrigue <garrigue at kurims.kyoto-u.ac.jp>,
        Claudio Sacerdoti Coen <sacerdot@cs.unibo.it>
Cc: lablgtk at kaba.or.jp
Subject: Re: GTree row selection event
In-Reply-To: <16306.4493.522709.269560 at akasha.ijm.jussieu.fr>
References: <20031107100532.GA17659 at cs.unibo.it>
	<20031110104118V.garrigue@kurims.kyoto-u.ac.jp>
	<20031110105058.GA19281@cs.unibo.it>
	<16306.4493.522709.269560@akasha.ijm.jussieu.fr>

 Olivier Andrieu [Wednesday 12 November 2003] :
 > It quite easy to construct an event_ops object even if the widget
 > class does not provide an #event method :
 > 
 > let make_event w =
 >  if w#misc#get_flag `NO_WINDOW
 >  then failwith "widget cannot receive events"
 >  else new GObj.event_ops w#as_widget
 > 
 > This function checks whether the widget has an associated GdkWindow
 > (IIRC it's a requirement for receiving X events and event signals) and
 > then builds an event_ops object.

Actually it is a bit more complicated than I thought and the
`NO_WINDOW check is not a very good idea because :
 - some widgets have the `NO_WINDOW flag but trigger these
   event-related signals (notably GtkButton)
 - all widgets can receive the expose event (it is "synthesized" by
   the parent container)

Jacques Garrigue [Thursday 13 November 2003] :
 > If a widget is able to handle events and has no #event method, this
 > is a bug of lablgtk and should be corrected.

I've grep'ed a bit the GTK+ source tree and I added an #event method
to the following widgets :
 - GtkTreeView (in GTree.view)
 - GtkScale (in GRange.range)
 - GtkRuler (in GRange.ruler)

-- 
   Olivier