vi / virtual_touchscreen

Simple evdev linux device driver and GUI program to simulate multitouch touchscreen

virtual_touchscreen

Simple virtual input device for testing things in Linux. Creates a character device and an input device.

.

Building

module

Building for current kernel:

make

Building for custom kernel (from a configured kernel directory):

make modules M=/path/to/virtual_touchscreen/

application

Use run virtual_touchscreen.clj or just use pre-built virtual_touchscreen.jar from Github releases

Using

Some testing

# insmod virtual_touchscreen.ko
# dmesg | grep virtual_touchscreen
virtual_touchscreen: Major=250
# cat /dev/virtual_touchscreen
Usage: write the following commands to /dev/virtual_touchscreen:
    x num  - move to (x, ...)
    y num  - move to (..., y)
    d 0    - touch down
    u 0    - touch up
    s slot - select multitouch slot (0 to 9)
    a flag - report if the selected slot is being touched
    e 0   - trigger input_mt_report_pointer_emulation
    X num - report x for the given slot
    Y num - report y for the given slot
    S 0   - sync (should be after every block of commands)
    M 0   - multitouch sync
    T num - tracking ID
    also 0123456789:; - arbitrary ABS_MT_ command (see linux/input.h)
  each command is char and int: sscanf("%c%d",...)
  <s>x and y are from 0 to 1023</s> Probe yourself range of x and y
  Each command is terminated with '\n'. Short writes == dropped commands.
  Read linux Documentation/input/multi-touch-protocol.txt to read about events

1# printf 'x 200\ny 300\nS 0\n' > /dev/virtual_touchscreen
1# printf 'd 0\nS 0\n' > /dev/virtual_touchscreen
1# printf 'u 0\nS 0\n' > /dev/virtual_touchscreen

2# hd /dev/input/event11 # or whatever udev assigns
# printf 'x 200\ny 300\nS 0\n' > /dev/virtual_touchscreen
# printf 'd 0\nS 0\n' > /dev/virtual_touchscreen
# printf 'u 0\nS 0\n' > /dev/virtual_touchscreen

And events should flow from the newly created input device:

# hd /dev/input/event11 # or whatever udev assigns
00000000  df 32 48 4f a6 10 02 00  03 00 00 00 c8 00 00 00  |.2HO............|
00000010  df 32 48 4f ab 10 02 00  03 00 01 00 2c 01 00 00  |.2HO........,...|
00000020  df 32 48 4f bf 10 02 00  00 00 00 00 00 00 00 00  |.2HO............|
00000030  e3 32 48 4f af af 09 00  01 00 4a 01 01 00 00 00  |.2HO......J.....|
00000040  e3 32 48 4f bc af 09 00  00 00 00 00 00 00 00 00  |.2HO............|
00000050  e7 32 48 4f 3d bb 05 00  01 00 4a 01 00 00 00 00  |.2HO=.....J.....|
00000060  e7 32 48 4f 50 bb 05 00  00 00 00 00 00 00 00 00  |.2HOP...........|

GUI

There is a GUI application that can also provide data for virtual touchscreen: virtual_touchscreen.clj. (pre-built bundled version; SHA256=917698e287e1b707e09c3040d6347f5f041d7a60fef0a6f5e51c2b93ccd39f3c, also available on Github Releases)

It listens port 9494 and provides virtual_touchscreen input for connected clients.

Example (checked with Clojure 1.3, may need updating):

hostA$  java -cp clojure.jar clojure.main virtual_touchscreen.clj

hostB#  nc hostA 9494 > /dev/virtual_touchscreen

Misc

There is also experimental script to read /dev/input/eventX of some real device and output data for virtual_touchscreen. It is long unmaintained although. Maybe see forks for alternative script.

Licence

Kernel module's licence is GPL. GUI app's license is MIT or Apache 2.0.

virtual_touchscreen's Issues

Script just says "killed"

Hi,

I know this is old, but I figured I'd ask anyway. I installed the kernel and can see the device (and the cat command returns the instructions), however when I did a test of simulating touch:

1# printf 'x 200\ny 300\nS 0\n' > /dev/virtual_touchscreen

I get back "Killed".

This is running Ubuntu 16.04 4.10.0-37 generic kernel.

Any suggestions for why this might be failing?

Can not find any event device

I'm running Ubuntu 14.04, with 3.x kernel.
After inserting the kernel module, I can't find any new event device

hd /dev/input/event11 # or whatever udev assigns

Would you give me some help? Thanks for your nice code.

install on a raspberry pi

Hello, I just have tried to install the virtual_touchscreen on a raspberry (raspbian), but I'm stumbling still on the first step "make". (I already have done apt-get update, and I tried sudo apt-get install raspberrypi-kernel-headers)

pi@raspberrypi:~/virtual_ctp/virtual_touchscreen-master $ make
make -C /lib/modules/`uname -r`/build M=$PWD modules
make[1]: *** /lib/modules/4.9.59-v7+/build: No such file or directory.  Stop.
Makefile:10: recipe for target 'default' failed
make: *** [default] Error 2

OR

pi@raspberrypi:~/virtual_ctp/virtual_touchscreen-master $ make modules M=/path/to/virtual_touchscreen/
make: *** No rule to make target 'modules'.  Stop.
pi@raspberrypi:~/virtual_ctp/virtual_touchscreen-master $ 

EDIT:
I suppose "make" is for building kernel, so I simply tried to compile the file, but now I think I have to add the "mt.h" File? Is that correct? I don't want build the kernel or such thing (to complicated for me)

pi@raspberrypi:~/virtual_ctp/virtual_touchscreen-master $ gcc -Wall -pthread -o virtual_touchscreen virtual_touchscreen.c
virtual_touchscreen.c:2:28: fatal error: linux/input/mt.h: No such file or directory
 #include <linux/input/mt.h>
                            ^
compilation terminated.
pi@raspberrypi:~/virtual_ctp/virtual_touchscreen-master $ 

evdev throwing an error

After the insmod or modprobe, the device appears and I can use libinput record or evtest for testing it and it works great, but it doesn't work in X. The X log shows this error

[    12.650] (EE) evdev: Touchscreen Virtual Device: Unable to query fd: Inappropriate ioctl for device

Which I think is connected to the TVD not working in the X.

What would have to be changed in the code to make the module work within X?

insmod: could not insert module virtual_touchscreen.ko: Key was rejected by service

Hello,

i am trying to install

insmod virtual_touchscreen.ko 
insmod: ERROR: could not insert module virtual_touchscreen.ko: Key was rejected by service

do you know a workaround ?

thanks

printf command does not do anything

Hi,

So I cloned the repo and tried to follow your instructions. I run "make" on the repo, run insmod on the .ko file, and saw the virtual touchscreen is there on /dev/input/event7. However, when I printf to this event, nothing happens and when I listen using hd, there is nothing being output (please see screenshot below). I also did not get anything when I do dmesg | grep virtual_touchscreen. Do you perhaps know why? Could you perhaps tell me what am I supposed to see on dmesg and hd everytime I run a command on the virtual touchscreen? I am using Ubuntu 20.04. Thank you!

There is no usable Makefile

This makefile consists of only one line, it's not usable.