Qt5 on PiScreen

Forums Technical Support for PiScreen Qt5 on PiScreen

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  • #4171
    TomMclaughlin
    Participant

    Hello All,

    For the past while I have been trying to get a Qt5 program to cross compile from my linux laptop to my Rpi2 with a PiScreen. I seem to have run into 2 problems

    1) to cross compile Qt onto the pi I needed to take the image from the SD card, copy it onto my laptop, mess with it, and then copy it back. Once I copy it back to the SD card, my touchscreen calibration is wrong. If I move the stylus right, the cursor goes down, left is up, up is left and down is right.

    I have tried recalibrating it but that does not seems to be working. In fact it makes it worse.

    Everything works fine if I attach a mouse

    2) I am able to cross compile programs and execute them on my pi. However, they are only displayed through the HDMI port. I found a post in these threads about copying the HDMI output to the PiScreen, but it leaves the program choppy and the desktop underneath 'bleeds through'

    Is there a way I can rotate the coordinates of the touchscreen so that it works properly again and also is there a way for me to get my program to change displays from the HDMI to the PiScreen?

    Thank you for your time,

    #4172
    Mark Williams
    Keymaster

    1)
    Have a look in /etc/X11/xinit/xinitrc and see if there are any lines like this;

    DISPLAY=:0 xinput --set-prop 'ADS7846 Touchscreen' 'Evdev Axes Swap' 1
    DISPLAY=:0 xinput --set-prop 'ADS7846 Touchscreen' 'Evdev Axis Inversion' 1 1

    If there are, delete them.
    Then delete the calibration file and then reboot to run the calibration program again.

    2)
    are you using fbcp? If so, this isn't really a good way to do it.. I consider this a sort of 'hack'.
    I am not familiar with Qt. However, in your code.. can you force it to display the output on a given framebuffer? If so.. use framebuffer /dev/fb1

    Mark --OzzMaker.com --

    #4807
    TomMclaughlin
    Participant

    Thanks for your reply (took a little bit of a break)

    I took a look into /etc/X11/xinit/xinitrc and didn't see what you were asking

    I have been trying to use the framebuffers but have been having some trouble. I figured I could use the same approach as X windows and replaced what I found in pi@raspberrypi ~ $ sudo nano /usr/share/X11/xorg.conf.d/99-fbturbo.conf

    with

    Section "Device"
            Identifier      "PiSCreen"
            Driver          "fbturbo"
            Option          "fbdev" "/dev/fb1"
    EndSection

    and then when I tried to get my program to launch I did this: ./myprogram -platform linuxfb LinuxFb:fb="/dev/fb1"

    But am still not getting it to work. Any additional thoughts would be very welcome

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