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Thread: Raspberry Pi + touchscreen

  1. #1
    Join Date
    Nov 2013
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    Angry Raspberry Pi + touchscreen

    Hi

    I'm writting application using 5.1.1 version on Pi (Qt is native build from sources done on Pi). I have connected touchscreen via USB and got some problems in application. Touchscreen is working on Pi (Wheezy) UI without any problems, but when my application is started it begins to work crazy. Application seems to detect touchscreen, but mouse cursor with touch screen is moved very fast, seems to be something wrong with calibration, application changed it somehow. I was trying to use tslib in different ways (like use calibration functionality inside application), calibrate touchscreen using tslib tests programs outside and use calibration file in application - no success. When application starts, touchscreen works verys strange (very fast moves). I'm using big display (TV 50") for that, so maybe here is some problem? (but why rest of system works fine)? I was also trying to run samples from Qt and the same effect, mosue cursor is going crazy with touchscreen. Any help would be very appreciated. Application is using QML and is started in fullscreen mode.

    Robert

  2. #2
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    Default Re: Raspberry Pi + touchscreen

    Maybe some hint - i've noticed that touch coordinates are fine, so only movement of cursor using touchpad is wrong. When application starts it has 30dpi dots per inch (could cause such problems?). I don't know where i should start looking for problems, driver for touchpad seems to work fine if it works on Pi desktop. So, some problem in Qt? But where i should start to search?

  3. #3
    Join Date
    Nov 2011
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    Default Re: Raspberry Pi + touchscreen

    It's possible this patch might help, although I'm not sure:

    https://codereview.qt-project.org/#change,81593

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