On Mon, Dec 29, 2014 at 08:07:31PM +0100, dustin wrote: > Hi, > > i recently started to play around with the input facilitys of X. My goal is > to develop a remote control for my PC and for that purpose i want to control > the mouse with an android tablet. (Maybe other embeded devices) > > I found a few ways to do this namely xtest and uinput/evdev (and untested > xlib/xcb). Both working out of the box but i think i'll stick with > uinput/evdev cuz i think this approach should work with libinput(wayland) as > well? One problem arises that i can't circumvent and this is the scrolling. > my first implementation works by simply emitting button 4/5 events like what > ordinary mouse wheels do (looking at xev xinput tools) but what i am rally > looking for is emitting "smooth scroll events"/"pixel perfect scrolling" > (whatever this means). I came across some articles from Peter Hutterer > talking about this and that Gnome implemented this. One can see this in live > action via touchpad and the epiphany webbrowser. What i discovered was, that > a client program has to catch XI2 events (XIDeviceEvent)and watch for > XI_Motion and its valuators. But i really don't know how to emit these? with > uinput/evdev even if i am emiting EV_REL, REL_WHEEL events and not button > 4/5 events i got ordinary scrolling. what is the "right way" to emit these > XIDeviceEvent/XI_Motion events (if these are really the ones i am looking > for) > > what i was seeing from xinput --test-xi2 for ordinary mouse wheels was > > EVENT type 17 (RawMotion) > device: 2 (10) > detail: 0 > valuators: > flags: > 2: -1.00 (-1.00) > > EVENT type 15 (RawButtonPress) > device: 2 (10) > detail: 5 > valuators: > flags: emulated > > EVENT type 16 (RawButtonRelease) > device: 2 (10) > detail: 5 > valuators: > flags: emulated > > As i understand this right the first XI_RawMotion is the "now" the regular > new event and the button presses are for compatibility and can be ignored > cuz of the "emulated" flag > > the valuator 2 means > > Class originated from: 10. Type: XIValuatorClass > Detail for Valuator 2: > Label: Rel Vert Wheel > Range: -1.000000 - -1.000000 > Resolution: 1 units/m > Mode: relative > > if i scroll with my touchpad i get > > EVENT type 17 (RawMotion) > device: 2 (13) > detail: 0 > valuators: > flags: > 3: 4.00 (4.00) > > there i have a valuator 3 which i guess means Rel Vert Scroll regarding to > this > > Class originated from: 13. Type: XIValuatorClass > Detail for Valuator 3: > Label: Rel Vert Scroll > Range: 0.000000 - -1.000000 > Resolution: 0 units/m > Mode: relative > > So the difference must somehow be with the different valuators. If so i just > don't know how i can influence this with uinput/evdev. Maybe its only doable > with xlib/xcb/xtest etc. i don't know. > > all i want is to simulate the "pixel perfect smooth scrolling" i get from > regular laptop touchpads so that apps who respond to this will do from my > application.
the output of xinput should also include a XIScrollClass. That contains information whether it's vertical/horizontal and refers to the valuator number. If such a class is present, the valuator listed is a scrolling valuator and should be interpreted as such. You don't have to do anything special in uinput, just send REL_WHEEL and the rest of the xorg stack will do the right thing. Though since REL_WHEEL is discreet, you won't get as much use out of smooth scrolling as you would from a touchpad. Cheers, Peter _______________________________________________ xorg@lists.x.org: X.Org support Archives: http://lists.freedesktop.org/archives/xorg Info: http://lists.x.org/mailman/listinfo/xorg Your subscription address: %(user_address)s
