I am looking for a way to inject wacom input into a running X server. I kind of get stuck at the beginning finding any resources about this topic.
There is a lot of information about how to inject keystrokes and mouse input, but thats not what i am looking for and it does not seem to simlutate wacom stuff.
Does anyone have any informations about this topic?
On Linux, the various input devices generate a variety of events.
For example,
Keyboards - EV_KEY
Mice - EV_REL
Tablets - EV_ABS
The events supported/generated by any particular input device can be identified by running xinput on the system with the input device connected to it as follows:
xinput --list <name of the connected input device>
A sample list of input devices created by connecting a Wacom tablet:
$ > xinput --list
⎡ Virtual core pointer id=2 [master pointer (3)]
⎜ ↳ Virtual core XTEST pointer id=4 [slave pointer (2)]
⎜ ↳ SynPS/2 Synaptics TouchPad id=14 [slave pointer (2)]
⎜ ↳ Wacom Intuos4 6x9 eraser id=17 [slave pointer (2)]
⎜ ↳ Wacom Intuos4 6x9 cursor id=18 [slave pointer (2)]
⎜ ↳ Wacom Intuos4 6x9 pad id=19 [slave pointer (2)]
⎜ ↳ Wacom Intuos4 6x9 stylus id=20 [slave pointer (2)]
⎣ Virtual core keyboard id=3 [master keyboard (2)]
↳ Virtual core XTEST keyboard id=5 [slave keyboard (3)]
↳ AT Translated Set 2 keyboard id=13 [slave keyboard (3)]
..and the list of input events supported/generated by one of the 4 Wacom devices that are registered to input events from the Wacom tablet:
$ > xinput --list "Wacom Intuos4 6x9 eraser"
Wacom Intuos4 6x9 eraser id=17 [slave pointer (2)]
Reporting 8 classes:
Class originated from: 17
Buttons supported: 9
Button labels: None None None None None None None None None
Button state:
Class originated from: 17
Keycodes supported: 248
Class originated from: 17
Detail for Valuator 0:
Label: Abs X
Range: 0.000000 - 44704.000000
Resolution: 200000 units/m
Mode: absolute
Current value: 0.000000
Class originated from: 17
Detail for Valuator 1:
Label: Abs Y
Range: 0.000000 - 27940.000000
Resolution: 200000 units/m
Mode: absolute
Current value: 0.000000
Class originated from: 17
Detail for Valuator 2:
Label: Abs Pressure
Range: 0.000000 - 2048.000000
Resolution: 1 units/m
Mode: absolute
Current value: 0.000000
Class originated from: 17
Detail for Valuator 3:
Label: Abs Tilt X
Range: -64.000000 - 63.000000
Resolution: 1 units/m
Mode: absolute
Current value: 0.000000
Class originated from: 17
Detail for Valuator 4:
Label: Abs Tilt Y
Range: -64.000000 - 63.000000
Resolution: 1 units/m
Mode: absolute
Current value: 0.000000
Class originated from: 17
Detail for Valuator 5:
Label: Abs Tilt Y
Range: -64.000000 - 63.000000
Resolution: 1 units/m
Mode: absolute
Current value: 0.000000
The above shows 9 buttons, and several axes with their corresponding min/max values for each type of input event(referred to by their lables).
For example, the absolute x axis has a min/max of 0 - 44704 units, with 20000 units/m. Presumably input events of type EV_ABS are generated only within this range for the X-axis.
Once the types of events being generated by the input device have been identified, it is easy to inject fake events into the Xinput queue using
uinputframework. A simple example is available here
As you intend to simulate a Wacom tablet, you would probably need to inject all the input events that a typical Wacom tablet generates when used.
xinputcan be used to monitor the sequence and timing of input events generated by an actual device as shown in this answer.
