#239 Wacom Tablet calibration tool (Ubuntu 14.04) not working correctly

Production
closed
nobody
calibration (1)
5
2014-08-24
2014-04-23
David
No

The calibration tool (in "Wacom tablet" the Settings Control Panel) in Ubuntu 14.04 appears to have a numerical bug. It looks like it's using the existing xinput calibration values to help work out the new ones, but that perhaps there's some offset at the side of the screen (or a global maximum value which its truncating at) meaning that every time you use it the pen shifts a little further out of calibration. The error grows with each calibration.

Perhaps someone could point me to the code where the calibration tool takes input and updates the xinput "Area" option for the stylus, and I can have a look to see where the problem is. (Sorry I don't know how to find it)

Discussion

  • Jason Gerecke
    Jason Gerecke
    2014-04-25

    A similar issue was reported against Ubuntu 13.04 [1] and is supposed to be fixed in GNOME 3.10 [2]. Do you know if Ubuntu 14.04 ships with that version of GNOME or not?

    The gnome-control-center code is a bit hard to follow, but it can all be found at [3]. The code responsible for the calculation is in calibrator/calibrator.c, while that which sets the Area property can be found in the run_calibration function in cc-wacom-page.c.

     
  • David
    David
    2014-04-25

    Thanks for the speedy reply. 14.04 seems to ship with a version just before GNOME 3.10, i.e. 3.9.x

    I think you're absolutely right about it being fixed in GNOME 3.10 (release notes describing an improvement in the calibration). So I suspect the bug has already been fixed but just not reached me yet.

    I have tried adding the GNOME 3.10 repositories and upgrading the gnome-control-center to version 3.10 and it works! (There were an initial 5 or 6 failures to calibrate which I suspect were caused by my badly wrong starting values) It now seems very stable, as long as I launch the gnome-control-center and use its calibration routine.

    Thus I think there was just likely a bug in earlier versions of GNOME (including 3.9.x) which has been fixed, but just not reached everyone yet.

     
  • Jason Gerecke
    Jason Gerecke
    2014-04-25

    Good to know. I'll mark this bug as closed since its fixed in the upstream GNOME. If you have an account at Ubuntu's bug tracker, you might want to update the bug I linked to to let the maintainers (and other users) know the current status as of 14.04 :)

     
  • Jason Gerecke
    Jason Gerecke
    2014-04-25

    • status: open --> closed