monitord - autorandr made easier

monitord runs a script when the display configuration is changed.

In your session startup script, start monitord with the command line it will execute when the display configuration changes.

Example

Here's an example with i3wm:

exec --no-startup-id monitord /path/to/myscript.sh someargs

Each time the display configuration is updated, myscript.sh someargs will be run.

myscript.sh can do anything. An example use case would be to use xrandr to change the display configuration according to the dock your laptop is currently plugged in.

You could therefore do something like this:

# Apply a display configuration according to the dock
# the laptop is currently plugged in.
# The dock is detected by it's network card in this example.

if ip l show enxdaabbccddeeff 2>&1 > /dev/null; then
        # dock a
        nmcli connection up ConnA
        "${HOME}/.screenlayout/preset-a.sh"
elif ip l show enxd11aa22bb33cc 2>&1 > /dev/null; then
        # dock b
        nmcli connection up ConnB
        "${HOME}/.screenlayout/preset-b.sh"
else
        # laptop only
        nmcli connection up WiFi
        "${HOME}/.screenlayout/laptop.sh"
fi

How it works

monitord adds a udev rule which detects display hardware changes. When a display change occurs, it triggers a systemd service which sends a signal (SIGUSR1) to all monitord processes.

The monitord processes are running in the users sessions and only get the permission level of their owner.