On Tue, Jun 20, 2017 at 05:07:44AM +0000, Vahe Oughourlian wrote: > On Mon, Jun 19, 2017 at 5:58 PM Peter Hutterer <[email protected]> > wrote: > > > 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 > > > > Sure, I'll keep an eye on 99703 and give it a shot when it comes out.
I've just attached a branch for testing to that bug, please give it a shot, we can revisit the other questions once we get that one sorted Cheers, Peter > > > 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. > > > > Completely agree. Mostly this is me working backwards from an existing > option in the old version to find a possible solution. > > > > > > I think fixing 99703 will remove most of your issues. > > > > I'm not sure in this case. While it looks like 99703 will solve the case > mid-movement, it doesn't really address the cases at the start of the > movement when two fingers are on the pad. > > > > > > > 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. > > > > I'm entirely sympathetic to your perspective here about changing existing > and expected behavior, and no doubt you'd hear from a cadre of unhappy > users if the behavior were to change. However, I'd like to push back here. > I think two fingers moving gives significantly more intention to the > gesture, and as I'm seeing in my experience, it's happening enough > unintentionally to me to raise the question. I don't think it makes sense > from a user perspective to have any two touch points anywhere on the pad > trigger a scroll. > > Adding a configuration seems like the wrong solution per the direction the > project is taking, but changing the existing behavior is also undesirable. > What kind of consideration might move you to change this scroll behavior? > > > > > > Cheers, > > Peter > > _______________________________________________ wayland-devel mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/wayland-devel
