[Wayland-bugs] [Bug 90942] Fix acceleration curve for touchpads

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=90942

            Bug ID: 90942
           Summary: Fix acceleration curve for touchpads
           Product: Wayland
           Version: unspecified
          Hardware: Other
                OS: All
            Status: NEW
          Severity: normal
          Priority: medium
         Component: libinput
          Assignee: wayland-bugs at lists.freedesktop.org
          Reporter: lisec.velimir at gmail.com

Acceleration curve used for mouse is also used on touchpads. Because of this
touchpads are not very precise. They're too fast. I've been playing around with
different acceleration curves for touchpads and this is what I've come up with:

touchpad_accel_profile_linear(struct motion_filter *filter,
                              void *data,
                              double speed_in,
                              uint64_t time)
{
    const double TP_MAGIC_SLOWDOWN = 0.4;
    double speed_out;

    speed_in *= TP_MAGIC_SLOWDOWN;

    struct pointer_accelerator *accel_filter =
        (struct pointer_accelerator *)filter;

    double s1, s2;
    const double max_accel = accel_filter->accel; /* unitless factor */
    const double threshold = accel_filter->threshold; /* units/ms */
    const double incline = accel_filter->incline;

    s1 = min(0.55, 0.35 + speed_in);
    s2 = speed_in + 0.15;

    speed_out = min(max_accel, s2 > 0.55 ? s2 : s1);

    return speed_out * TP_MAGIC_SLOWDOWN;
}

I personally quite like this curve and speed, but that's probably because I use
similar curve and speed in X11 so I'm used to it.

The thing that's missing is treshold and incline variables. Currently I can't
incorporate those into the formula because i don't know how to change mouse
speed. I'm running ubuntu 14.04 and I'm testing libinput in weston. Is there a
way to change mouse speed from weston.ini?

-- 
You are receiving this mail because:
You are the assignee for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.freedesktop.org/archives/wayland-bugs/attachments/20150611/a15c355f/attachment.html>