Best way to achieve very slow pointer motion? (for accessibility)

[Colomban Wendling]

Le 28/11/2018 à 16:14, Colomban Wendling a écrit :
> Le 28/11/2018 à 02:15, Peter Hutterer a écrit :
>> On Tue, Nov 27, 2018 at 11:25:05AM +0100, Colomban Wendling wrote:
>>> Are there other, more appropriate options?
>>> Basically, what I'd like to achieve is similar to being able to set the
>>> "Accel Speed" to a value way under -1.  If there are no better options,
>>> I can consider adding a "enable pointer acceleration" user setting which
>>> would control whether the "adaptive" or "flat" profile is used, but I'd
>>> like to avoid it if possible to keep the user setting simple and
>>> understandable.
>>
>> Honestly, I think you're going about it the wrong way. You want an
>> accessibility feature and you're looking for hacks and knobs that you can
>> (ab)use to get the result you want.
>>
>> The side-effect of this is that you make life miserable for both sides. Any
>> change in libinput could break whatever knobs you find and you're forcing
>> libinput to maintain behaviour that wasn't intended to work this way,
>> possibly blocking improvements.
> 
> That's the reason I'm asking: because I don't feel great about the
> current options I found.

I see however that you mentioned that selection of the acceleration
profile may have had an option in gnome-tweak-tool in
https://gitlab.freedesktop.org/libinput/libinput/issues/187.  And just
having such a setting should not put any burden on libinput, as it'd
merely select the profile, and not try to map the different profile
speeds with magic numbers that just happen to look like they are working.

If that's the best I can do for now, I can live with this although it's
not perfect.

>> PS: yes, obviously this is dependend on Wayland because in X the server
>> controls the pointer and you're mostly out of luck.
> 
> Well, this "only" suggests I would need a way to do that with X in the
> meantime.  What about a multiplication factor in xf86-input-libinput?
> […]
> 
> Would such a parameter be acceptable for X, or could you point me to a
> better place for this if not?

Any opinion on this?  As said, that could be the X pendant of a Wayland
compositor option to do the same, that I could use until I can rely on
Wayland.

Regards,
Colomban