On Tue, Jul 31, 2018 at 07:48:46PM +0200, Josh Simmons wrote: > Hello there, > > I've found what seems to be some interesting behaviour in the events > returned from xinput2 while using the libinput driver with the "FLAT" > profile.
the "flat" profile disables acceleration, so what comes out of the device is what you get. if the device gives you a 1/1 delta, you get a 1/1 delta movement. https://gitlab.freedesktop.org/libinput/libinput/blob/master/src/filter-flat.c#L47 and since devices don't give you anything < 1 unit delta, subpixel isn't really a thing unless you lower the speed setting. > It seems that changing the sensitivity (via the gnome control panel) > only changes the scale of the events sent by libinput, and not the > frequency (in device coordinates) in which they are reported to the > application. (Either that or they're somehow losing device coordinate > sub-pixel precision at some point along the way). > > The result of this is that with the standard 100% sensitivity the > driver will report to X only events that are multiples of 1 pixel. > With a sensitivity of 200% it will only report events that are > multiples of 2 pixels. With a sensitivity of 50% it will report with a > 0.5 pixel resolution and so on making the default and higher > sensitivities feel very janky and not at all smooth. > > My work around is just to slide the sensitivity as low as I can and > use my mouse's DPI adjustment to get to where I want to be, but it > seems like a bug that all the sub-pixel resolution is missing from the > default configuration at the very least. yeah, that's basically the expected behaviour, or at least the "implemented behaviour". What the mouse gives you is what you get. https://gitlab.freedesktop.org/libinput/libinput/blob/master/src/filter-flat.c#L77 Cheers, Peter > > Thanks, and apologies if I've missed this issue when searching the archive. > Josh. _______________________________________________ wayland-devel mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/wayland-devel
