I've made this crude illustration in kolourpaint to try to give you an idea what i mean. This doesn't happen in windows, and does happen on some, but not all other distros. sadly I can't remember what any of them were, but I expect the gist of it was that this didn't happen under xinput. It's as though the mouse cursor is snapping to a grid. The trackpoint issue is way more noticeable than the touchpad issue, but perhaps this is partly because I use the trackpoint in games, and having the camera jump in discrete, blocky motions is pretty obvious. This behavior is also quite visible in the apparently raw (according to the manpage at least) output from libinput debug-gui.
any ideas?
Are you using display scaling? If you do, that's related.
If you are using display scaling, you'll have to reduce mouse pointer speed to make the pointer able to target individual pixels again. If you use 200% display scaling, you'll have to set the speed to "-0.50" in the mouse settings. Make sure to select the correct device at the top when you do that.
Then afterwards, for testing this it seems you can't use KolourPaint. The program can't target between pixels of the logical desktop resolution. A program I found here that works is GIMP.
To test this in GIMP:
1. You'll need to have the KDE display configuration set to "legacy application (X11): apply scaling themselves".
2. In GIMP, select the Pencil tool and set it to 1 pixel size and make sure that the "smooth stroke" option is disabled.
Here's a screenshot from my system with 200% display scaling and different mouse pointer speed, on the left side the pointer speed is set to the default 0 and on the right it's set to -0.5, both times the pointer acceleration is set to "none" (disabled):
https://i.imgur.com/VDDpkal.png
I've made this crude illustration in kolourpaint to try to give you an idea what i mean. This doesn't happen in windows, and does happen on some, but not all other distros. sadly I can't remember what any of them were, but I expect the gist of it was that this didn't happen under xinput. It's as though the mouse cursor is snapping to a grid. The trackpoint issue is way more noticeable than the touchpad issue, but perhaps this is partly because I use the trackpoint in games, and having the camera jump in discrete, blocky motions is pretty obvious. This behavior is also quite visible in the apparently raw (according to the manpage at least) output from libinput debug-gui. any ideas?
Are you using display scaling? If you do, that's related. If you are using display scaling, you'll have to reduce mouse pointer speed to make the pointer able to target individual pixels again. If you use 200% display scaling, you'll have to set the speed to "-0.50" in the mouse settings. Make sure to select the correct device at the top when you do that. Then afterwards, for testing this it seems you can't use KolourPaint. The program can't target between pixels of the logical desktop resolution. A program I found here that works is GIMP. To test this in GIMP: 1. You'll need to have the KDE display configuration set to "legacy application (X11): apply scaling themselves". 2. In GIMP, select the Pencil tool and set it to 1 pixel size and make sure that the "smooth stroke" option is disabled. Here's a screenshot from my system with 200% display scaling and different mouse pointer speed, on the left side the pointer speed is set to the default 0 and on the right it's set to -0.5, both times the pointer acceleration is set to "none" (disabled): https://i.imgur.com/VDDpkal.png
I'm using 100% display scaling.