Re:Linux touchpad like a MacBook Pro, May 2020 update
by lsbussell on Tuesday May 05, 2020 @12:22PM
(#23081723)
The acceleration curve on the Mac trackpad is unparalleled. I wonder if it’s possible to reverse engineer it using a mouse (or a “fake” mouse via a teensy or something). That being said, I can’t stand using a mouse with the same acceleration, I have to install an app to disable it.
Re:Linux touchpad like a MacBook Pro, May 2020 update
by rconti on Tuesday May 05, 2020 @12:10PM
(#23081585)
Interesting. Lower latency? Or maybe doing some predictive slowing by over-accelerating the slowing as soon as it detects a change in speed or pressure?
Re:Linux touchpad like a MacBook Pro, May 2020 update
by Aeolos on Tuesday May 05, 2020 @12:42PM
(#23081941)
You've hit the nail on the head. The real difference is input latency.
Tweaking acceleration curves will not help overcome latency of 2-3 frames which is common on Linux compositors (33-50 ms of delay, causing target overshoots).
Re:Linux touchpad like a MacBook Pro, May 2020 update
by skrtskrt on Tuesday May 05, 2020 @12:18PM
(#23081668)
I'm thinking either sensitivity is lowered as deceleration begins, or deceleration is over-emphasized as you say. I can move really fast then stop completely dead even as I'm sure my by-no-means-steady hands are not that precise and are probably still very slightly moving as I'm "stopped".
Mac allows the cursor to move quickly, but where it differs & excels is how fast it decelerates or stops the cursor.
On Linux, I am always overshooting what I'm trying to click on even when I make the mouse tracking speed very very slow. On Mac I can keep the tracking speed high and jump around quickly but still manage to stop right where I need to every time.
So either, it's faster to register you're slowing down/stopping OR it slows down at a faster rate than your finger is slowing down (vs faithfully tracking your finger)... or both?
Edit: This is true for the handling of external mice too, it's not just the trackpad. The difference is night and day, and overshooting things is frustrating with a normal mouse as well as the touchpad.