Re: Multiple documents

["David M. Cook" <dave davidcook org>]

On Tue, Aug 26, 2003 at 03:15:20PM +0000, Chris Garrett wrote:

> That is pretty much the way I thought I would have to do it.  However, I am 
> experiencing some confusion about how to ensure that callbacks from the 
> canvas end up resulting in changes on the correct image.  

I use a bit of a hack for this (in Python, but think it should be fairly
clear how to translate to C.)

    def canHandleRequests(self):
        """Whether this controller can handle requests, i.e. its toplevel
        has been mapped and is not hidden, and its view has focus."""
        toplevel = self.view.get_toplevel()
        return (toplevel.window
                and not (toplevel.window.get_state() # WITHDRAWN=hidden
                         & gtk.gdk.WINDOW_STATE_WITHDRAWN) 
                and self.view.is_focus() )

toplevel.window is the gdk window for the toplevel.  Substitute whatever
widget you want to handle signals for "view".  In my callbacks I check this
before handling the signal.  I'm kind of hoping someone will tell me I'm
crazy and there's a more elegant way to do this ;}

Another way has already been described: keep track of what window should
currently handle the signal.  But then you still need a way to decide if a
window should handle a signal.  In a notebook this is easy; just get the
current page.

Dave Cook