R devel - Apr 2005 - Embedded R and x11

Hi,

I'm working on a frontend for R. I have R running in a separate thread in my
application using Rf_initEmbeddedR, and I'm using R_tryEval to run commands 
in R (i.e. I don't run the mainloop).
Everything works fine, except the x11-device: I can open x11-windows and paint 
to them alright from R. However, the x11-window does not respond to any 
events. E.g. clicking the close-button simply does not close the window and 
the contents in the window do not get refreshed when it was hidden by other 
windows.
I figured that the reason for this might be, that R_ProcessEvents () and 
handleEvent () in devX11.c do not get called (of course I might be completely 
wrong?). So I tried calling R_ProcessEvents () manually, but I can't get
that
to link (unresolved symbol R_ProcessEvents).
Any hints on how I can get this to work?

Thanks
Thomas

Hi again,
> I figured that the reason for this might be, that R_ProcessEvents () and
> handleEvent () in devX11.c do not get called (of course I might be
> completely wrong?). So I tried calling R_ProcessEvents () manually, but I
> can't get that to link (unresolved symbol R_ProcessEvents).
> Any hints on how I can get this to work?
ok, I figured it out. For the record, the following code (called periodically 
when there is nothing else to do) does the trick:

#include "R_ext/eventloop.h"

void processX11 () {
	extern InputHandler *R_InputHandlers;
	InputHandler *handler = R_InputHandlers;
	while (handler) {
		if (handler->activity == XActivity) {
			handler->handler ((void*) 0);
		}
		handler = handler->next;
	}
}

Thomas

I think you are barking up the wrong tree.  If you want to use an 
event-driven sub-system you need to run an event loop.

There is a lot of new information in 2.1.0 on building a front-end.
Please read it.

On Wed, 20 Apr 2005, Thomas Friedrichsmeier wrote:
> I'm working on a frontend for R. I have R running in a separate thread
in my
> application using Rf_initEmbeddedR, and I'm using R_tryEval to run
commands
> in R (i.e. I don't run the mainloop).
> Everything works fine, except the x11-device: I can open x11-windows and
paint
> to them alright from R. However, the x11-window does not respond to any
> events. E.g. clicking the close-button simply does not close the window and
> the contents in the window do not get refreshed when it was hidden by other
> windows.
> I figured that the reason for this might be, that R_ProcessEvents () and
> handleEvent () in devX11.c do not get called (of course I might be
completely
> wrong?). So I tried calling R_ProcessEvents () manually, but I can't
get that
> to link (unresolved symbol R_ProcessEvents).
> Any hints on how I can get this to work?
-- 
Brian D. Ripley,                  ripley@stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

> I think you are barking up the wrong tree.  If you want to use an
> event-driven sub-system you need to run an event loop.
Well, but I only want part of R's event loop, namely handling of some
specific
X11-events. Of course, I do have a sort of event-loop, except that the main
category of "events" is requests coming from the main
application/thread. For
this it's simply more practical to run my "own" event loop. The
only problem
was how to trigger processing of X11-events from there.

Anyway, you will see in my follow-up, that I found a solution that does just
what I want.
> There is a lot of new information in 2.1.0 on building a front-end.
> Please read it.
Yes, I've seen that, and it's very helpful compared to the documentation
available when I had last checked (pre 2.0.0).

Regards
Thomas Friedrichsmeier

P.S.: In case you're interested, the project I'm working on is this:
http://rkward.sourceforge.net