On Tue, 16 Feb 1999, Kieran O' Sullivan wrote:
It's only allowed for a single application to select for
buttonpress events in a window. In the case of the root
window, the window manager already does that before any
app, so you can't do what you want directly. The options
are:
1) disable root window button press in the window manager,
if it's possible (some window managers have an option for that)
2) do a passive grab for button presses in the root window
(XGrabButton)
3) use an existing window manager protocol to tell the
window manager to relay button events to your app (take a
look in teh GNOME wm hints)
4) rethink whether you really need button events from the
root window
--
Alfredo
> I was on about this befor and I tried the suggestion that I got back and
> some of it was good but SelectInput() causes errors when it is applied to
> the root window. The root window seems to think that you are trying to
> change its assributes so your program crashes. The following was
> something I came up with and for some reason it doesn't work the program
> can process its own events but it gets nothing from the root window. I
> have not tried the function with any other window and I know that the root
> window is listening to ButtonPress events.
>
> root_win = RootWindow(display, root_screen); /* Sets a window structure
> equal to root window. There is nothing wrong with this statement because
> I have used it in a QueryTre() function successfully */
>
> /* there is a continuous loop here */
> /* after the program has processed its own events it does the following */
>
> if(!XCheckWindowEvent(display, root_win, ButtonPressMask|PointerMotionMask, &report2))
>
> {/* nothing to do because there are no events */}
> /* XCheckWindowEvent() is used because it checks the event que and
> if it doesn't find anything it returns False and doesn't balck allowing
> the program to do what it has to do with out waiting for events. */
>
> else
>
> {
>
> printf("\n Something happended ont the root window \n");
>
> switch (report2.type)
>
> {
> case ButtonPress:
>
> printf("\nButton Press on root window \n");
>
> break;
>
>
> case MotionNotify:
>
> XQueryPointer (display, win, &rep_root, &rep_child,
>
> &rep_rootx, &rep_rooty, &dx, &dy, &rep_mask);
>
> printf("\nThe pointer was queried %d, %d\n",dx, dy);
>
> break;
>
> default:
>
> break;
>
> } /* End of case for report2 */
>
> } /* Enf of if */
>
> } /* End of While loop that processes all the events */
>
> If anyone can help I would be very grateful.
>
> _____________________________________________________________________
> Kieran O' Sullivan
> http://snet.wit.ie/BlindPenguin
>
>
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>