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    [solved] Touchscreen calibration issue on Qt 4.8.4 on ARM

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    • M
      marcin100 last edited by

      I'm having hard time calibrating the touchscreen when running Qt on the i.mx6 board (SabreLite)

      the tslib calibration works ok and I can see the cursor following my finger.

      However when I run any Qt app (either mine or one of the Qt demos included with Qt) the cursor seems to be moving at different pace than the finger. Seems like cursor is moving across a much larger space than the screen and it goes off the screen when the finger is still about 30% away from the edge.

      Why the Qt does not use tslib calibration data?
      Is there a way to define the touchscreen size which I maybe missed?

      I have come across posts where other people had similar issue but no solutions.

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      • SGaist
        SGaist Lifetime Qt Champion last edited by

        Hi,

        Are you sure you are using the tslib input when starting your application ?
        Did you configure all tslib related environment variables ?

        Interested in AI ? www.idiap.ch
        Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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        • M
          marcin100 last edited by

          It is entirely possible that I have missed something since I'm a beginner in this area. To be honest, I am not sure how to specify tsllib intput when starting my Qt application.
          I would appreciate a short code example, if possible.

          FYI: I am using QtQuick(qml) for my gui, but this should not matter.. I think.

          I did configure the tslib env vars:
          export LD_LIBRARY_PATH=/usr/lib
          export TSLIB_TSEVENTTYPE=INPUT
          export TSLIB_CONSOLEDEVICE=none
          export TSLIB_FBDEVICE=/dev/fb0
          export TSLIB_CALIBFILE=/etc/pointercal
          export TSLIB_CONFFILE=/etc/ts.conf
          export TSLIB_PLUGINDIR=/usr/lib/ts
          export TSLIB_TSDEVICE=/dev/input/event1

          and the:
          TSLIB_CONFFILE contents:

          module_raw input
          module pthres pmin=1
          module variance delta=30
          module dejitter delta=100
          module linear

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          • M
            marcin100 last edited by

            UPDATE:
            problem solved by updating env variables as shown below:

            export LD_LIBRARY_PATH=/usr/lib
            export TSLIB_TSEVENTTYPE=INPUT
            export QTDIR=/home/martin/Qt_E/qt-4.8.4_tslib/
            export QWS_MOUSE_PROTO=tslib:/dev/input/event1
            export TSLIB_CONSOLEDEVICE=none
            export TSLIB_FBDEVICE=/dev/fb0
            export TSLIB_CALIBFILE=/etc/pointercal
            export TSLIB_CONFFILE=/etc/ts.conf
            export TSLIB_PLUGINDIR=/usr/lib/ts
            export TSLIB_TSDEVICE=/dev/input/event1
            export QWS_DISPLAY=LinuxFB:mmWidth=800:mmHeight=480

            I have not nailed down which exact line fixed it but I have a feeling the QWS_DISPLAY is the one.

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            • SGaist
              SGaist Lifetime Qt Champion last edited by

              Great you found out !
              Since it's the only line that was missing, my guess is that Qt was maybe using a different plugin (I don't remember which is the default), couldn't find the correct screen size or was given a wrong size (but I might be wrong).

              Don't forget to set the thread's title to solved so other forum users may know a solution has been found :)

              Interested in AI ? www.idiap.ch
              Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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              • G
                giri babu last edited by

                hi have the same problem where do i find the tslib env vars file to edit,sorry i am new to this kindly help me if i am wrong.

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                • SGaist
                  SGaist Lifetime Qt Champion last edited by

                  Hi and welcome to devnet,

                  For testing purpose, you can simply set the variables on the command line before calling your application

                  Interested in AI ? www.idiap.ch
                  Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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                  • G
                    giri babu last edited by

                    hi,

                    i have one more problem now i am using qt4e-demo-image and i get smart home demo on the target and says xres=800 and yres=460 after this i am not able to calibrate the touch screen its a touch screen from freescale scale its mciimx lvds connected to lvds 1 of sbaresd board the display says TOUCH CROSSHAIR TO CALIBRATE but if i touch it does not detect anything it does not work, kindly let me know what changes i have to make and where..

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                    • SGaist
                      SGaist Lifetime Qt Champion last edited by

                      That I can't, I don't have such a setup at hand. You should have a look at the documentation of your board/provider.

                      Interested in AI ? www.idiap.ch
                      Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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