Qt 5.10.1 EGLFS libinput Touchscreen rotation

chtioub

Hi,

I try to do my first development on Rapsberri PI 3 and Qt.
I use Qt 5.10.1 with cross compilation for Raspberry 3
I have a 7" LCD with USB touchscreen rotate a 90°.

I found the solution to rotate the screen with config.txt adding :
display_hdmi_rotate=3

and the touchscreen is rotated with adding call a batch script in
~/.config/lxsession/LXDE-pi/autostrart
the script is :
xinput set-prop 'FocalTech Lab FTxxxx MultiTouch' 'Coordinate Transformation Matrix' 0 -1 1 1 0 0 0 0 1

So the touchscreen is working in startx

My problem is with programs in Qt using EGLFS and libinput. I can not rotate my touchscreen.
I read a lot a post talking about wayland, tslib, ts_calibrate, evdev.... But I think it is for old development.
I am pretty sure there is a simple solution for nowadays.

Sébastien

chtioub

Hi,

Can someone help me about this issue.

3 month I turn around and do not understand why I cannot rotate touch screen only with Qt application.

Thanks

Diracsbracket

@chtioub
Have a look at:
https://doc.qt.io/qt-5/embedded-linux.html

Since you have a multitouch panel it seems, you can use the evdevtouch plugin:

export QT_QPA_GENERIC_PLUGINS=evdevtouch:/dev/input/touchscreen

Replace /dev/input/touchscreen by /dev/input/eventX with the correct value for X if you haven't setup a udev rule yet.

The same with rotation:

export QT_QPA_GENERIC_PLUGINS=evdevtouch:/dev/input/touchscreen:rotate=90

chtioub

@Diracsbracket said in Qt 5.10.1 EGLFS libinput Touchscreen rotation:

QT_QPA_GENERIC_PLUGINS

ouch !

3 months to turn around, and with 3 lines, you solve my problem !
Many thanks.

Now I would like to understand a little why I cannot use libinput as it is the native driver for ELGFS.

This are no solution with libinput ?
I trough evdev was an old solution

chtioub

Hi,

Well, evdevtouch plugin seem to be completely buggy.
The rotation woks very well but afin 1 to 10 secondes, the touch does not woks anymore.
Even with example programs.

I have this information :
TouchPointPressed without previous release event QQuickEventPoint(accepted:false state:Pressed scenePos:QPointF(249.631,798.957) id:2000002 timeHeld:0)

I have to reset the application to work.

Is there any solution to workaround this bug or a solution with libinput ?