On Fri, Jun 16, 2017 at 05:48:31PM +0000, Vahe Oughourlian wrote: > On Thu, Jun 15, 2017 at 3:23 PM Peter Hutterer <[email protected]> > wrote: > > > On Tue, Jun 13, 2017 at 01:46:12AM +0000, Vahe Oughourlian wrote: > > > I'm working with a Dell XPS 15 9650 using libinput. Using the Synaptics > > > driver, a property is available to set the maximum distance two fingers > > may > > > be apart before a two-finger scroll can be triggered, called "Synaptics > > > Two-Finger Width." At the moment, two fingers anywhere on the touchpad > > will > > > switch it over to a two-finger scroll. > > > > > > I ran across a post from Peter Hutterer ( > > > > > https://who-t.blogspot.de/2016/04/why-libinput-doesnt-have-lot-of-config.html > > ) > > > discussing the intention to minimize options in libinput, and there > > doesn't > > > seem to be a setting that affects this behavior that I could find. Given > > > that, is the most appropriate thing to file a bug for this particular > > > trackpad to have a reasonable default added for this device, or is this a > > > setting libinput eventually intends to support? Or is this setting > > already > > > available? > > > > it's not an available configuration, no. But the main question is what > > you're actually trying to achive? I'm assuming that any finger distance > > limits are not the issue per se but that there's something else that > > affects > > how you can interact. > > > > Cheers, > > Peter > > > > > There are a couple common cases: > > 1. My left thumb may drift onto the upper left corner of the touchpad (in > the usual home-row typing position) while my right hand is controlling the > touchpad. Despite the 70mm-ish distance between the fingers, the next > cursor motion by the right hand is treated as a two-finger scroll.
https://bugs.freedesktop.org/show_bug.cgi?id=99703 > 2. I often use the physical click as part of a drag-and-highlight. While > there are dead zones at the bottom of the mouse for the virtual buttons, if > my thumb isn't quite low enough on the right hand, the moment before > actually clicking the physical button underneath the trackpad will turn > into a two-finger scroll. This also can occur at the end of the click as > I'm lifting the thumb, and the next motion is a scroll. not quite the same but similar to the bug above. I think that's something we'd have to revisit once we manage to get a hand on 99703 > My intention was to set the distance between two fingers such that they'd > have to be much closer together (within 20mm, for example) to avoid these > accidental scroll events. tbh, I don't think that's the right solution and that's also why there's no config option for it. Any distance-based guessing of intentions should always be internal to libinput because once we expose the option we'll have to keep it around forever. And exposing an option promises behaviour. I think fixing 99703 will remove most of your issues. > One thing I have also noticed on other trackpads (on other OSes, > admittedly) is that both fingers seem to have to be in motion to trigger a > two finger scroll, whereas I seem to be able to trigger a two-finger scroll > on the Dell's trackpad by moving one finger while two fingers are on the > trackpad at a time. Perhaps that's the solution here? yeah, that's been a long-standing feature of the 2fg scroll on linux. not sure we can/should get rid of that. Cheers, Peter _______________________________________________ wayland-devel mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/wayland-devel
