Re: insert idle/timeout handler into gtk loop

[Havoc Pennington <hp redhat com>]

"Riswick, J.G.A. van" <J G A v Riswick tue nl> writes:
> In a gnome applet I'm writing, I'd like to monitor if
> the user changed workspaces. The function gnome_wmhints_
> get_current_workspace() returns the workspace number. So
> I figured I'd insert an idle handler into the gtk main
> loop, with low priority, that can monitor workspace 
> changes if gtk is not doing anything else. This works,
> but even when I use the lowest priority (G_PRIORITY_LOW)
> for inserting the handler, the app takes up so much cpu 
> time that my laptop fan has to blow all the time (50% 
> cpu time on a 800Mhz pIII). So for now I solved the 
> problem by using a 100ms timeout instead of an idle 
> handler. I was wondering if here is anothere way of 
> monitoring a quantity and it also seems strange to me that 
> an idle handler with the lowest priority takes up so
> much cpu time.

You need to monitor PropertyNotify for the X property that indicates
the current workspace. i.e. ask for PropertyNotify on the root
window with gdk_window_set_events(GDK_ROOT_PARENT()), then check 
for that hint in the PropertyNotify.

The GNOME hints are on the way out anyway though, module "libwnck" in
GNOME CVS has a library for using the new hints. It requires GTK 2
however.

Havoc