VNC server for Linux framebuffer devices.
The goal is to access remote embedded Linux systems without X. Implemented features: remote display, touchscreen, keyboard, rotation Not implemented: file transfer, ..
Working configurations:
without rotation:
- 1 bit/pixel
- 8 bit/pixel
- 16 bit/pixel
- 24 bit/pixel
- 32 bit/pixel
with rotation:
- 1 bit/pixel
- 8 bit/pixel
- 16 bit/pixel
- 24 bit/pixel
- 32 bit/pixel
The code is based on a LibVNC example for Android: https://github.com/LibVNC/libvncserver/blob/master/examples/androidvncserver.c
Dependency:
sudo apt-get install libvncserver-dev
There are 2 options: CMake or qmake
Using cmake:
mkdir -p build && cd build
cmake ..
make
Using qmake:
mkdir -p build && cd build
qmake ../framebuffer-vncserver.pro
make
# ./framebuffer-vncserver -h
framebuffer-vncserver [-f device] [-p port] [-t touchscreen] [-k keyboard] [-r rotation] [-v] [-h]
-p port: VNC port, default is 5900
-f device: framebuffer device node, default is /dev/fb0
-k device: keyboard device node (example: /dev/input/event0)
-t device: touchscreen device node (example:/dev/input/event2)
-r degrees: framebuffer rotation, default is 0
-v: verbose
-h: print this help
To run at startup as a service using systemd, edit the file fbvnc.service make sure the path and command line arguments are correct and then run:
sudo cp fbvnc.service /etc/systemd/system/
sudo systemctl enable fbvnc.service
sudo systemctl start fbvcn.serviceLinux Virtual Frame Buffer kernel object (vfb.ko) is used for this test. https://cateee.net/lkddb/web-lkddb/FB_VIRTUAL.html
Local computer:
# install
sudo apt install vagrant virtualbox xtightvncviewer
# after framebuffer-vncserver start
vncviewer localhost
vagrant up
vagrant ssh
Inside vagrant box:
sudo su
cd /home/vagrant/buildc/
# build framebuffer-vncserver
make
# set resolution, color depth
fbset -g 640 480 640 480 16
# restart framebuffer-vncserver
killall framebuffer-vncserver;./framebuffer-vncserver -t /dev/input/ms -k /dev/input/kbd &
# set test pattern or ..
fb-test
# draw random rectangles or ..
rect
# display a GUI or ...
qmlscene -platform linuxfb -plugin evdevmouse:/dev/input/ms:abs -plugin evdevkeyboard:/dev/input/kbd:grab=1
This generates patterns with different resolutions and color depths (on local computer):
pip3 install fabric vncdotool python-vagrant entrypoint2
python3 vfb.py
| rotation | color | fbtest | qmlscene | gradient |
|---|---|---|---|---|
| 0 | 1 |  |
||
| 0 | 8 |  |
 |
|
| 0 | 16 |  |
 |
 |
| 0 | 24 |  |
 |
 |
| 0 | 32 |  |
 |
 |
| 90 | 16 |  |
 |
 |
| 180 | 16 |  |
 |
 |
| 270 | 16 |  |
 |
 |
$ (evtest /dev/input/event0 &) ;./framebuffer-vncserver -t /dev/input/event0 -v
...
Initializing touch device /dev/input/event0 ...
x:(0 4095) y:(0 4095)
...
Supported events:
Event type 0 (EV_SYN)
Event type 1 (EV_KEY)
Event code 330 (BTN_TOUCH)
Event type 3 (EV_ABS)
Event code 0 (ABS_X)
Value 1970
Min 0
Max 4095
Event code 1 (ABS_Y)
Value 1745
Min 0
Max 4095
Event code 24 (ABS_PRESSURE)
Value 0
Min 0
Max 255
...
Got ptrevent: 0001 (x=186, y=570)
Event: time 1580221917.655639, type 1 (EV_KEY), code 330 (BTN_TOUCH), value 1
Event: time 1580221917.655639, type 3 (EV_ABS), code 0 (ABS_X), value 1586
Event: time 1580221917.655639, type 3 (EV_ABS), code 1 (ABS_Y), value 2733
Event: time 1580221917.655639, -------------- SYN_REPORT ------------
injectTouchEvent (screen(186,570) -> touch(1586,2733), mouse=1)
...
Got ptrevent: 0000 (x=186, y=570)
Event: time 1580221918.516897, type 1 (EV_KEY), code 330 (BTN_TOUCH), value 0
Event: time 1580221918.516897, -------------- SYN_REPORT ------------
injectTouchEvent (screen(186,570) -> touch(1586,2733), mouse=0)
$ (evtest /dev/input/event2 &) ;./framebuffer-vncserver -t /dev/input/event2 -v
...
Supported events:
Event type 0 (EV_SYN)
Event type 1 (EV_KEY)
Event code 330 (BTN_TOUCH)
Event type 3 (EV_ABS)
Event code 0 (ABS_X)
Value 245
Min 0
Max 480
Event code 1 (ABS_Y)
Value 485
Min 0
Max 854
Event code 47 (ABS_MT_SLOT)
Value 4
Min 0
Max 4
Event code 48 (ABS_MT_TOUCH_MAJOR)
Value 0
Min 0
Max 255
Event code 50 (ABS_MT_WIDTH_MAJOR)
Value 0
Min 0
Max 255
Event code 53 (ABS_MT_POSITION_X)
Value 0
Min 0
Max 480
Event code 54 (ABS_MT_POSITION_Y)
Value 0
Min 0
Max 854
Event code 57 (ABS_MT_TRACKING_ID)
Value 0
Min 0
Max 65535
...
Initializing touch device /dev/input/event2 ...
x:(0 480) y:(0 854)
...
Got ptrevent: 0001 (x=237, y=528)
Event: time 1580221680.870277, type 3 (EV_ABS), code 57 (ABS_MT_TRACKING_ID), value 0
Event: time 1580221680.870277, type 1 (EV_KEY), code 330 (BTN_TOUCH), value 1
Event: time 1580221680.870277, type 3 (EV_ABS), code 53 (ABS_MT_POSITION_X), value 237
Event: time 1580221680.870277, type 3 (EV_ABS), code 54 (ABS_MT_POSITION_Y), value 528
Event: time 1580221680.870277, type 3 (EV_ABS), code 0 (ABS_X), value 237
Event: time 1580221680.870277, type 3 (EV_ABS), code 1 (ABS_Y), value 528
Event: time 1580221680.870277, -------------- SYN_REPORT ------------
injectTouchEvent (screen(237,528) -> touch(237,528), mouse=1)
...
Got ptrevent: 0000 (x=237, y=528)
Event: time 1580221681.190716, type 3 (EV_ABS), code 57 (ABS_MT_TRACKING_ID), value -1
Event: time 1580221681.190716, type 1 (EV_KEY), code 330 (BTN_TOUCH), value 0
Event: time 1580221681.190716, -------------- SYN_REPORT ------------
injectTouchEvent (screen(237,528) -> touch(237,528), mouse=0)