Can I change the vertical scaling independent from the horizontal scaling when using my Bamboo stylus in Relative mode?

Question

Can I change the vertical scaling independent from the horizontal scaling when using my stylus in Relative mode?

I use a Wacom Bamboo Pen & Touch, with the stylus in Relative mode (instead of the default Absolute). I use two monitors side-by-side, giving me a screen area of 3840x1080 pixels (3.5 aspect ratio). The tablet is 14720x9200 "units" (1.6 aspect ratio).

If I move my stylus 1 cm in the horizontal direction it will move much further on the screen than if I move it in the vertical direction (3.5/1.6 = 2.18 times further). How can I change this?

I have tried changing two settings:

• Area, as suggested in a related answer, but this seems to affect only the active area of the physical tablet
• Coordinate Transformation Matrix, but this seems to only have an effect in Absolute mode.

Answer 1

After sending a message to the wacom developers mailing list:

The two settings used above can not resolve the issue. It is a bug in X server/XInput.

The problem lies in the difference between x, y scales. We used to unify the scale in wacom_drv.so when mapping and screen information were considered inside the driver (in linuxwacom package). The evidence of this work is still in the comments of xf86-input-wacom. Refer to line 611 of wcmCommon.c[*]. However, the actual scale match can not be fully implemented inside the driver any more since the new factorX/Y does not have screen info.

Screen information and relative mode acceleration are pushed out into X server. Mapping and scale unification should be processed by in X server/Xinput too.

So, by design, the scale is unified so users can draw circles in relative mode, without changing settings. - Ping Cheng (Full Email)

And then from Peter:

yeah, that's a bug in the server, this should be exposed by the ptraccel code but it isn't yet. I've never found the time to properly investigate where it's going wrong, but you can even see this behaviour when you add a monitor - suddenly the acceleration factor goes up by a fair bit.

As Ping said, this cannot be fixed in the driver, we need the server to handle this correctly. - Peter Hutterer (Full Email)

In conclusion, I think the best action is to report the bug and champion a developer to sort through the code to get a fix in place.