Re: Updating GUI during long operation

[Chris Vine <chris cvine freeserve co uk>]

On Sun, 21 Apr 2013 11:33:45 +0100
Chris Vine <chris cvine freeserve co uk> wrote:
> On Sat, 20 Apr 2013 16:25:50 -0700
> Kip Warner <kip thevertigo com> wrote:
> > On Sat, 2013-04-20 at 23:35 +0100, Chris Vine wrote:
> > > If you have a main loop running, this is completely unnecessary,
> > > unless you are doing something to block the loop, which you
> > > shouldn't do.
> >
> > Hey Chris. Although your response was not particularly constructive,
> > I'll give you the benefit of the doubt. Perhaps I am doing something
> > unnecessary to block the loop which I should not do. Take a look at
> > the method defined at 287:
>
> Thank you for your condescension: an interesting way of asking for
> help.
>
> The code to which you refer does not block, so something else is
> blocking the loop. The point you need to understand is that in normal
> code there will very rarely be a reason to call "while
> Gtk.events_pending(): Gtk.main_iteration()" in a well behaved
> application (although that call does not appear in the file to which
> you refer), and it would need special justification and explanation.
> Furthermore your original posting appeared to indicate ("including the
> following within it...") that those iteration calls were made in some
> idle handler somewhere, which on the face of it is pointless.

By the way, rather than overt blocking it may just be that the program
is putting more graphical events through the main loop than it can
handle.  Since any one main loop is single threaded there is very
little you can do about that, except reduce the rate at which you pass
events to the main loop.  Since any thread can have its own main loop
you may be able to pass some event-driven work off to another loop,
but any graphical (GDK/GTK) events have to go to the main loop, and
there is no easy way out of that.

Chris