Automatic Stylus (Pen) Rotate Orientation

stylus-rotate.sh

#!/bin/sh
# Automatic stylus (pen) orientation for HP Spectre x360
# adapted by Efrem Rensi
#  This is a fix for an apparent bug in Cinnamon whereby System Settings >> General >> Automatic Screen Rotation
#   Rotates the screen and touch functionality, but the pen orientation does not rotate

# Based on chadm's script at https://linuxappfinder.com/blog/auto_screen_rotation_in_ubuntu.

# Receives input from monitor-sensor (part of iio-sensor-proxy package) and sets the touchscreen
# orientation based on the accellerometer positionn. We assume that the display rotation is 
# handled by Linux Mint 18.1, Cinnamon 3.2.7. If this is not the case, add the appropriate
# xrandr command into each case block.

# This script should be added to startup applications for the user.


PEN=18

# The device number PEN=18 is obtained by running
#   xinput
# and reading the output, which for my HP Spectre x360 is:
# ⎡ Virtual core pointer                      id=2    [master pointer  (3)]
# ⎜   ↳ Virtual core XTEST pointer                id=4    [slave  pointer  (2)]
# ⎜   ↳ ELAN2514:00 04F3:2592                     id=11   [slave  pointer  (2)]
# ⎜   ↳ ELAN2514:00 04F3:2592 Pen Pen (0)         id=18   [slave  pointer  (2)]
# ⎜   ↳ SynPS/2 Synaptics TouchPad                id=15   [slave  pointer  (2)]
# + other lines


# Kill any existing monitor-sensor instance, for example if manually invoking
# from a terminal for testing.
killall monitor-sensor

# Launch monitor-sensor and store the output in a RAM based file that can be checked by the rest of the script.
# We use the RAM based file system to save wear where an SSD is being used.
monitor-sensor > /dev/shm/sensor.log 2>&1 &

# Parse output of monitor sensor to get the new orientation whenever the log file is updated
# Possibles are: normal, bottom-up, right-up, left-up
# Light data will be ignored
while inotifywait -e modify /dev/shm/sensor.log; do

# Read the last few lines that were added to the file and get the last orientation line.
ORIENTATION=$(tail /dev/shm/sensor.log | grep 'orientation' | tail -1 | grep -oE '[^ ]+$')

echo "$ORIENTATION"
# Set the actions to be taken for each possible orientation
case "$ORIENTATION" in

bottom-up)
xinput set-prop $PEN 'Coordinate Transformation Matrix' -1 0 1 0 -1 1 0 0 1;;

normal)
xinput set-prop $PEN 'Coordinate Transformation Matrix' 1 0 0 0 1 0 0 0 1;;

right-up)
xinput set-prop $PEN 'Coordinate Transformation Matrix' 0 1 0 -1 0 1 0 0 1;;

left-up)
xinput set-prop $PEN 'Coordinate Transformation Matrix' 0 -1 1 1 0 0 0 0 1;;

esac
done

# On stopping this script, don't forget that "monitor-sensor" is still running - hence the "killall" !

Thank you so much! I barely have any coding knowledge and I was able to read through your instructions and get this working. I second the recommendation of running the code through the terminal first. Just copy/paste the code directly into the terminal all at once, but be sure to change the PEN ID at the very beginning to whatever corresponds on your computer like the instructions say. This way you can test it out, and make sure that you aren't missing any packages. My terminal notified me when I first ran that I was missing inotifywait, but that was a quick and easy install.

Thanks again, this was my first GitHub code package that I've ever used!