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From: frivold@san18.erg.sri.com (Thane J. Frivold)
Newsgroups: comp.windows.x
Subject: XSendEvent question
Message-ID: <32797@sparkyfs.istc.sri.com>
Date: 6 Nov 90 07:02:27 GMT
Sender: news@sparkyfs.istc.sri.com
Reply-To: frivold@erg.sri.com.UUCP (Thane J. Frivold)
Organization: SRI International, Menlo Park CA
Lines: 129


	I am currently working on an application (a modified `twm' to
be exact) that allows for a certain amount of `remote control' of X11
applications.  Once a common application has been determined, a
controlling user's host replicates the pertinent X11 events to all the
listening hosts.  All event delivery to the selected application is
done via calls to XSendEvent().

	The event capture is done by creating an InputOnly `capture
window' whose parent is the selected application (target) window and
whose event mask has all bits set, except `PointerMotionHintMask'.

	The intent is to intercept all events normally destined for
the selected application in order to decide, as a function of control
state, whether or not the event should be propogated to the other
hosts (as well as delivered locally).

	Currently, the application *does* work for client applications
that have a *single* X11 window, but I have been unable to deliver the
events to *multiple* window applications (e.g. xcalc or xwebster).
	
	Could someone please help me see either 1) the futility of my
aspirations or preferably 2) the flaw in my approach and the required
solution.

	
	Here is the code I am using to select the application window:


/* NOTE: Select_Window() is taken, as is, from the file `dsimple.c'
 * 	 found with the standard application `xwd'.
 */

Window
SelectWindowFromUser(display)

Display *display;
 
{
    Window      target = Select_Window(display);
 
    if( target != None )
    {
        Window          root;
        int             result;
        int             idummy;
        unsigned int    udummy;
         
        result = XGetGeometry(display,
                              target,
                              &root,
                              &idummy, &idummy,
                              &udummy, &udummy,
                              &udummy, &udummy);
 
        /* Look for the true `client' window */
        if( result && target != root)
            target = XmuClientWindow(display, target);

        /* Make sure we didn't get the `root' window lest we render
         * the window manager itself useless by intercepting all events.
         */
        if( target == root )
            target = None;
    }

    return target;
}

	The code fragment that handles the control case is:

    .
    .
    .

    /* Was this event `captured' from the target application? */
    if( Event.xany.window == captureWindow )
    {
        Bool ProcessRemoteXEvent();

	/* Should this event be propogated to the listeners? */
        if (ProcessRemoteXEvent(&Event) )
        {
	    /* If so, deliver the event locally as well */
            XSendEvent(dpy, targetWindow, False, 0L, &Event);
        }
    }    

    /* Otherwise handle the event as usual */
    else
        DispatchEvent();

    .
    .
    .

	And the code to handle the listen case is:

    .
    .
    .

    /* Insert the display for the local host */
    Event.xany.display = dpy;

    XSendEvent(dpy, targetWindow, False, 0L, &Event);
  
    .
    .
    .

	Thank you in advance for any light you can shed on my problem.


					-Thane J. Frivold
					 Software Engineer
					 Geoscience & Engineering Center
		
					 SRI International
					 333 Ravenswood Avenue
					 Menlo Park, CA  94025
					 Mail Stop: EJ329

					 Office: (415) 859-2786
					 FAX:    (415) 325-4812	
					 EMAIL:	 frivold@erg.sri.com  -or-
					 	 frivold@unix.sri.com
					-Thane J. Frivold
					 frivold@erg.sri.com