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.
best regards,
Dustin Bensing
_______________________________________________
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
