Re: Odd Linux behavior

[Lindley M French <lfrench1 gmu edu>]

It seems to me that I'm not going to be able to get an expose event to propagate down to the window which is scrolled off the edge of my GtkScrolledWindow. Nothing I've tried has worked.

So the question becomes----can I simply call my expose handler directly and expect to access (at least) the back buffer without trouble? I don't know what sort of tricks the expose event causes which are necessary to set up drawing.

----- Original Message -----
From: Lindley M French <lfrench1 gmu edu>
Date: Thursday, August 20, 2009 3:21 pm
Subject: Re: Odd Linux behavior

> I'll try to throw something basic together. Until I have time for 
> that, however, a few more details have emerged.
> 
> I have code which requests that my GUI take a screenshot of one of 
> its windows. So it needs to generate an expose event for that 
> window whether it's visible or not. To this end, I use 
> gdk_window_process_updates() to force an expose event.
> 
> The problem is that I have several windows arranged in an hbox, 
> and they aren't all visible 100% of the time. There's a scroll 
> bar, and you can scroll to the various windows.
> 
> When a window is scrolled into view as far as the hbox is 
> concerned, gdk_window_process_events() works as expected even if 
> the entire GUI is minimized. But when a window is *not* scrolled 
> into view, it doesn't----the expose handler is never called.
> 
> I wondered if maybe this was a result of the window being unmapped 
> when it's scrolled out of view, but this doesn't seem to be the 
> case as far as I can tell.
> 
> ----- Original Message -----
> From: richard boaz <ivor boaz gmail com>
> Date: Thursday, August 20, 2009 1:31 pm
> Subject: Re: Odd Linux behavior
> 
> > hi,
> > 
> > when you first reported this, i tried re-creating with my own 
> > program, but
> > couldn't.
> > 
> > the lack of response you've received is only most likely due to 
> no 
> > one else
> > having experienced this.
> > 
> > which suspiciously points to the code.
> > 
> > i think you might make progress on this if you:
> > 
> >   1. reduce your problem to a simple "hollow world" example
> >   2. that continues to demonstrate the problem
> >   3. if possible, test as well on a different platforms (not 
> sure 
> > if you've
> >   demonstrated this on more than one already)
> >   4. re-submit the worldly code to the list
> > 
> > having actual code is sometimes critical, especially when the 
> > behavior is
> > unfamiliar.
> > 
> > cheers,
> > 
> > richard
> > 
> > On Thu, Aug 20, 2009 at 6:55 PM, Lindley M French 
> > <lfrench1 gmu edu> wrote:
> > 
> > > Okay, I've determined that this new behavior is still just a 
> > symptom of
> > > expose events not occurring.
> > >
> > > Still curious why expose events don't happen when the program 
> is 
> > bg'd but
> > > on-screen, though.
> > >
> > > ----- Original Message -----
> > > From: Lindley M French <lfrench1 gmu edu>
> > > Date: Thursday, August 20, 2009 12:07 pm
> > > Subject: Odd Linux behavior
> > >
> > > > About a month ago I posted that my GTK+ app stopped getting 
> expose> > > events when I bg'd the app in Linux. Got no response, 
> though.> > >
> > > > Well, it seems to be worse than that.
> > > >
> > > > I'm running the program through Putty from a Windows 
> machine. 
> > If I
> > > > minimize the main window, or even just lock the screen,
> > > > *something* stops working. Can't say for sure what it is, 
> but I've
> > > > got a console program which periodically sends the GUI 
> updates via
> > > > pipes, and I left the combo running last night with the screen
> > > > locked.....and zero progress was made. I get in this morning,
> > > > unlock the screen, and it starts going again.
> > > >
> > > > This can only mean that the pipes are filling up and not being
> > > > emptied, which means that *something* is blocking 
> unexpectedly in
> > > > the GUI.
> > > >
> > > > Does anyone have the first clue what I should be looking for to
> > > > fix this? I'm using GTK+ 2.12.
> > > >
> > > _______________________________________________
> > > gtk-list mailing list
> > > gtk-list gnome org
> > > http://mail.gnome.org/mailman/listinfo/gtk-list
> > >
> > 
>