[Interest] [Development] Qt5 QML TouchPoint pressure always return -1, but QWidget tabletEvent works well

[Shawn Rutledge]

On Wed, Jul 16, 2014 at 12:09:36PM +0800, Leslie Zhai wrote:
> Hi Qt developers,
> 
> In Qt5.3.1 qtdeclarative/examples/quick/touchinteraction,
> 
> There is MultiPointTouchArea and TouchPoint example, but TouchPoint 
> touch1.pressure, it always print out -1

I'm getting pressure 1 when pressed and 0 when released on a touchscreen.
Many touchscreens don't offer pressure valuators.  If you are getting -1
I think that's a bug.

What kind of touch hardware are you using?  Since you mentioned the tablet
example, maybe it's an Intuos 5 or something like that?  We hope to support
it eventually; I'm trying to acquire one for testing.

> Why?! because Qt5 removed X11 and Xi relatived part? 
> https://github.com/krre/AprilBrush-Desktop/blob/master/cpp/wacom/wacom_unix.cpp#L31

We've been adding functionality, but Xi2 is different than Xi1 which Qt 4 was using.
It is not allowed to use both APIs... they're quite incompatible.  Xi1 is obsolete;
we need to use Xi >= 2.2 in order to have multi-touch support at all.  So now it seems 
there is more work to be done to get the Intuos touch support working correctly with Xi2.
See https://bugreports.qt-project.org/browse/QTBUG-39572