Bug 390761 (libinput-touchpad-kcm-mmb-emulation)

Summary: Expose Libinput middle click button/emulation settings
Product: [Applications] systemsettings Reporter: Nate Graham <nate>
Component: kcm_touchpadAssignee: Plasma Bugs List <plasma-bugs>
Status: RESOLVED WORKSFORME    
Severity: normal CC: bugseforuns, shtetldik, subdiff
Priority: NOR Keywords: usability
Version: 5.17.5   
Target Milestone: ---   
Platform: Other   
OS: Linux   
Latest Commit: Version Fixed In:
Bug Depends on:    
Bug Blocks: 383379    

Description Nate Graham 2018-02-20 03:28:47 UTC
The libinput touchpad KCM needs user-visible settings to:
- Turn on and off Libinput's virtual middle-click button
- Turn on and off middle-click emulation (e.g. simulate middle click when both physical touchpad buttons (if available) are pressed at the same time

On X11, these settings can be toggled via `xinput`, but on Wayland, the only way to do it is if the GUI configuration tool exposes the features.

See also https://gitlab.gnome.org/GNOME/gnome-tweaks/issues/82
Comment 1 Shmerl 2018-02-20 03:44:31 UTC
This should apply to mice too, not just touchpads.

For example, under X I use this:

Example (for my case), to query:

 xinput --list-props "Logitech G400s Optical Gaming Mouse"
Device 'Logitech G400s Optical Gaming Mouse':
...
        libinput Middle Emulation Enabled (288):        1
...

To set:

xinput set-prop "Logitech G400s Optical Gaming Mouse" "libinput Middle Emulation Enabled" 1

Something on Wayland to do that would be useful.
Comment 2 Roman Gilg 2018-03-18 21:49:04 UTC
What is Libinput's virtual middle-click button?

On Wayland the Touchpad KCM has an Emulate middle button checkbox. And I just tested, that it works. Do you mean something else?
Comment 3 Shmerl 2018-03-18 22:51:03 UTC
(In reply to Roman Gilg from comment #2)
> What is Libinput's virtual middle-click button?
> 
> On Wayland the Touchpad KCM has an Emulate middle button checkbox. And I
> just tested, that it works. Do you mean something else?

For mice, middle click emulation means making left and right click simultaneously, to produce middle click. It helps to relieve strain on the fingers a lot (clicking the scroll wheel is really uncomfortable).

I suppose it's not the same setting as one for touchpads.
Comment 4 Roman Gilg 2018-03-18 23:29:38 UTC
Yea, I was more interested in the "virtual middle-click button".

The emulation will work with
* https://phabricator.kde.org/D11468 on Wayland and
* https://phabricator.kde.org/D11469 on X.
Comment 5 Nate Graham 2018-03-19 04:15:28 UTC
You're right, my mistake: the "Emulate Middle Button" does indeed already adequately control this. Turning it on gets rid of Libinput's annoying virtual middle button for my touchpad, turning it into an extension of the virtual left-click button like I would expect (so the left-click button is 2/3 of the width, and the right-click button is the remaining 1/3).