[Development] QT4.8.5 issue: multi-touch message cannot handled by "close" button

[Duan Fugang-B38611]

From: Rutledge Shawn <Shawn.Rutledge at digia.com>
Data: Friday, September 13, 2013 2:48 PM

> > We use the X.Org X Server 1.14.0 + QT4.8.5 to do one demo, but I  catch
> one issue: multi-touch message is not handled by "close" button.
> >
> > I use egalax touchscreen for the multi-touch test.
> > After kernel up, evtest test the multi-touch message, all pass. Use
> xinput to do the test, also pass.
> >
> > Open one QT app, all multi-touch message can be processed, but the
> window of the app cannot be closed by click the "X" in the right-up region.
> > I test GNOME destop with the same kernel,  any apps' window can be
> closed.
> >
> > So, It is strange, maybe it is KDE issue for multi-touch ?
> > Any response is appreciative.
> 
> This X button is the one provided by the window manager, right?
Yes, I think any QT app windows are managed by window manager.

> If you
> are running KDE then it must be kwin.  (Which is probably still using Qt 4)
> But it probably relies on mouse emulation at some level to detect pressing
> that button. 
>From Xorg.0.log: [360470.340] (II) evdev: eGalax Touch Screen: No buttons found, faking one.
The Linux egalax driver don't report button event. Close window of apps need " BTN_TOUCH" event ?

The current egalax driver support multitouch events:
root@ /# mtdev-test /dev/input/event0
supported mt events:
   ABS_MT_TOUCH_MAJOR
   ABS_MT_WIDTH_MAJOR
   ABS_MT_POSITION_X
   ABS_MT_POSITION_Y
   ABS_MT_TRACKING_ID
 

> Maybe the egalax driver or the X server does it, so that any
> legacy X11 apps will work.  (You can try really old X apps that definitely
> don't support touch, like xman, xmessage etc.)  If you have a widget-based
> application with a QPushButton, or a qml application with a MouseArea, can
> you press those via the touchscreen?  because they also need to get mouse
> events rather than touch events (so far).
> 
> Which driver is the X server using for the touchscreen?  (check
> /var/log/Xorg.0.log) _______________________________________________