Non-square pixels on 7" touchscreen

Apr 22, 2017 2 Replies

For some unfathomable reason the 7" touchscreen has rectangular pixels.



I can't imagine why anyone thought this was a good idea. It makes it useless as a device that has to display an image of anything unless you like distorted images.



Is it possible correct by scaling the video output from the Pi?



Daniele


I am almost certain it is, but I haven't a clue what the magic spell would be.

I'd imagine deep in the bowels of xorg.conf, is away of telling it that the display is bent.

Mmm. After a few minutes probing, it looks like there is a 'Displaysize' directive in Xorg.conf that takes two parameters - the X and Y pixels per inch.

Edit (or create) /etc/X11/xorg.conf and put in this

Section "Monitor" Identifier "Touchscreen" VendorName "Wombatronic Industries" ModelName "Gargleblaster 8000" HorizSync 30 - 50 VertRefresh 60 DisplaySize 650 406 EndSection

and play around with the numbers if it makes a difference. Obviously you will have top reboot the x server between changes

If that doesn't work, there is a program called xrandr that can be used to interrogate and set parameters

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But the poster there ended up having to use a startup script to invoke it., because he never found a way to make the changes permanent.

I am now off firmly outside my sphere of competence, so I will sign off.

Good luck.

Ideas are more powerful than guns. We would not let our enemies have guns, why should we let them have ideas? Josef Stalin

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I've used xrandr to pan around the pokey display on a eeepc. Yup it goes in a startup script to set the desired resolution.

No, there doesn't seem to be a "save settings" option.

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Bah, and indeed, Humbug

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