[PATCH libinput 0/7] tablet: add support for relative x/y motion deltas

Jason Gerecke killertofu at gmail.com
Fri Jan 15 14:49:16 PST 2016

On Thu, Jan 14, 2016 at 4:26 PM, Peter Hutterer
<peter.hutterer at who-t.net> wrote:
> This patchset adds support for relative motion to the tablet branch. AFAICT,
> this is the last large feature that was still missing.
> The approach is notably different to the current X driver. There we
> toggle a property in the driver to switch the tablet into relative mode and
> then only send out relative events. The property works per tool.
> libinput's approach is to always calculate relative motion and provide both
> absolute and relative motion for each event. The caller must decide which
> tool should use which type of motion.
> Unlike the X driver, the relative motion is converted into a pixel-like
> motion vector that can be used like the mouse motion. if a caller wants
> mm-based movement they can easily calculate the deltas themselves anyway.
> Pointer acceleration is quite simple atm, it's a flat profile and the speed
> setting simply multiplies the vector. Can be extended later if need be.
> Cheers,
>   Peter

Looks good! I don't see any obvious problems, though I'm still not
100% familiar with the codebase. For the set:

Acked-by: Jason Gerecke <jason.gerecke at wacom.com>

Now instead of four in the eights place /
you’ve got three, ‘Cause you added one  /
(That is to say, eight) to the two,     /
But you can’t take seven from three,    /
So you look at the sixty-fours....

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