GTK3 and XINPUT_2

["Joe Woodward" <jw terrafix co uk>]

I'm running an embedded platform with GTK3 3.2.0 on a modern Xorg (1.12.0).

I have xvkbd (a virtual keyboard for X) and use xcalc to test it, and key presses on 
xvkbd are seen on xcalc (as expected).

If I build GTK3 with "--disable-xinput" then key presses on the xvkbd are seen in any 
GTK3 application.

However, if I build GTK3 without "--disable-xinput" (i.e. using XINPUT_2) key presses 
on xvkbd are no longer seen in any GTK3 application.

The touchscreen works with and without "--disable-xinput" specified, and if I plug in a 
USB keyboard then key-presses are seen in GTK3, so the XINPUT is working to some 
extent.

So my question are:
- how do I go about debugging this?
- how should I implement a virtual keyboard for use with GTK3 and XINPUT_2 (I'm 
assuming the X-calls performed by xvkbd are no longer sufficient)?
- what am I missing?!

Really, I'd like to move to 3.4 but I can't do that until I get an on-screen keyboard 
working :)

Cheers,
Joe



For reference (with no USB keyboard plugged in):

# xinput list
? Virtual core pointer                          id=2    [master pointer  (3)]
?   ? Virtual core XTEST pointer                id=4    [slave  pointer  (2)]
?   ? Touchscreen                               id=6    [slave  pointer  (2)]
? Virtual core keyboard                         id=3    [master keyboard (2)]
    ? Virtual core XTEST keyboard               id=5    [slave  keyboard (3)]
    ? <default keyboard>                        id=7    [slave  keyboard (3)]



And the following is a function I use to send key presses to an application's root 
window (that works with "--disable-xinput", but fails without it):

/* Cribbed slightly from the sources for xvkbd (an X virtual keyboard).
*/
static void _SendAsXEvent (KeySym keySym, gint shift)
{
  GdkWindow *gdkWindow;
  Display *target_dpy;
  Window cur_focus;
  gint revert_to;
  XKeyEvent event;
  gint keycode, shiftKeycode;

  /* Get the root window, and from this get the root X-display.
  */
  gdkWindow = gdk_get_default_root_window ();
  target_dpy = GDK_WINDOW_XDISPLAY (gdkWindow);

  /* Get the input focus.
  */
  XGetInputFocus (target_dpy, &cur_focus, &revert_to);

  /* Set up the event.
  */
  keycode = XKeysymToKeycode(target_dpy, keySym);
  shiftKeycode = XKeysymToKeycode(target_dpy, XK_Shift_L);
  event.display = target_dpy;
  event.window = cur_focus;
  event.root = RootWindow(event.display, DefaultScreen(event.display));
  event.subwindow = None;
  event.time = CurrentTime;
  event.x = 1;
  event.y = 1;
  event.x_root = 1;
  event.y_root = 1;
  event.same_screen = TRUE;
  event.state = 0;

  /* Check if we should send a shift.
  */
  if (shift) {
    event.type = KeyPress;
    event.keycode = shiftKeycode;
    XSendEvent (event.display, event.window, TRUE, KeyPressMask, (XEvent *)&event);
    event.state |= ShiftMask;
  }

  /* Send the press.
  */
  event.type = KeyPress;
  event.keycode = keycode;
  XSendEvent (event.display, event.window, TRUE, KeyPressMask, (XEvent *)&event);

  /* Send the release.
  */
  event.type = KeyRelease;
  event.keycode = keycode;
  XSendEvent (event.display, event.window, TRUE, KeyPressMask, (XEvent *)&event);

  /* Check if we should release the shift.
  */
  if (shift) {
    event.type = KeyRelease;
    event.keycode = shiftKeycode;
    XSendEvent (event.display, event.window, TRUE, KeyPressMask, (XEvent *)&event);
  }
}