Display rotation

This application will rotate screen and pointer (mouse, touchscreen, etc...) based on an accelerometer axis values.

Requirements

A X server is required. X applications such as xrandr (rotate display) and xinput (rotate pointer) are required too.

The code has been developped using the ADXL345 accelerometer, I'll recommend any accelerometer compatible with the adafruit-circuitpython-adxl34x Python library. Have a look to the Smart'Gic Abstract RPi API.

Because this accelerometer is connected to an I2C bus, an I2C bus is required. The code has been developped for Raspberry Pi but should work for any other platforms supporting I2C bus and able to run Python code.

Retrieve available monitors and pointers

xrandr will provide a list of available monitors/TV connected to your device.

xrandr --listmonitors
Monitors: 1
 0: +*HDMI-1 1080/1210x1920/680+0+0  HDMI-1

xinput will provide a list of available pointers (mouse, touchscreen, etc...) connected to your device.

xinput list
⎡ Virtual core pointer                    	id=2	[master pointer  (3)]
⎜   ↳ Virtual core XTEST pointer              	id=4	[slave  pointer  (2)]
⎜   ↳ Touch p303 Touch Device,99-20P Mouse    	id=7	[slave  pointer  (2)]
⎜   ↳ Touch p303 Touch Device,99-20P          	id=8	[slave  pointer  (2)]
⎣ Virtual core keyboard                   	id=3	[master keyboard (2)]
    ↳ Virtual core XTEST keyboard             	id=5	[slave  keyboard (3)]
    ↳ Touch p303 Touch Device,99-20P Keyboard 	id=6	[slave  keyboard (3)]

Installation

Some environment variables should be defined to match your setup.

Variables	Description	Default
INTERVAL	Check the accelerometer every iNTERVAL (in second)	1
THRESHOLD	Define when the axis reach a point of action	10
AXIS	Which axis to check (x, y, z)	x
MONITOR	Interface name where the monitor is connected	HDMI-1
POINTER	Name of the mouse, touchscreen, etc... to rotate	Touch p303 Touch Device,99-20P
ORIENTATION	Direction where the monitor will be rorated	right

Virtualenv installation

git clone https://github.com/smartgic/display-rotation.git
cd display-rotation
python3 -m venvs ~/venvs/display-rotation
source ~/venvs/display-rotation/bin/activate
pip install -r requirements.txt
cd app
export POINTER="Logitech M325"
python rotation.py

Docker installation

Supported architectures for Docker smartgic/display-rotation image.

Architecture	Information
amd64	Such as AMD and Intel processors
arm/v6	Such as Raspberry Pi 1
arm/v7	Such as Raspberry Pi 2/3/4
arm64	Such as Raspberry Pi 4 64-bit
ppc64	Such as PowerPC 64 platforms

The container needs to be authenticated to access the X Server and run the GUI. One way to do it is to use xauth (part of the xauth package on Debian/Ubuntu) which will generate a X authentication token. This token will have to be mounted as a volume within the container to be then used via the XAUTHORITY environment variable.

$ touch ~/.docker.xauth
$ xauth nlist :0 | sed -e 's/^..../ffff/' | xauth -f ~/.docker.xauth nmerge -

docker run -d \
    --volume /sys:/sys:ro \
    --volume /tmp/.X11-unix:/tmp/.X11-unix \
    --volume ~/.docker.xauth:/tmp/.docker.xauth:ro \
    --device /dev/i2c-1 \
    --env DISPLAY=:0 \
    --env XAUTHORITY=/tmp/.docker.xauth \
    --env THRESHOLD=10 \
    --env AXIS=x \
    --env MONITOR=HDMI-1 \
    --env POINTER="Logitech M325" \
    --env INTERVAL=1 \
    --env ORIENTATION=right \
    --name display_rotation \
    smartgic/display-rotation:latest

/dev/i2c-1 could change depending the hardware used (i2c from Raspberry Pi 4B).

Docker Compose installation

Make sure docker-compose is installed if not use your package manager or pip.

git clone https://github.com/smartgic/display-rotation.git
cd display-rotation
docker-compose up -d

Credits

Developed by Smart"Gic.