Wacom configuration daemon for Linux

wacom_hotplug.sh

#!/bin/bash
# This script can be run in the background, where it will attempt to
# handle configuration of all Wacom devices that are currently plugged
# in, as well as any Wacom devices that may be plugged in later. It
# does this by monitoring the system for hotplug events and then using
# xsetwacom to apply the appropriate configuration.
#
# This should be useful for users of alternative desktop environments
# (e.g. XFCE, MATE, Enlightenment, etc.) which don't provide their own
# Wacom control panels or daemons. Its potentially also useful for even
# GNOME users as a way of working around its buggy handling of ExpressKeys
# with low-end Bamboo/Intuos tablets.
#
# To use, simply adjust the configuration below. Each named tablet may have
# several lines of configuration, the text of which is simply the part of
# the 'xsetwacom' command which you would normally type out after the
# device name. For instance, P["foo"]="bar\nbaz" is interpreted by this
# script as a request to run `xsetwacom set "foo" bar` as well as
# `xsetwacom set "foo" baz`.

declare -A P
export P

########################################################################
# BEGIN EDITS HERE
########################################################################

if [ x"${XDG_CURRENT_DESKTOP}" == x"GNOME" ]; then
	# Some settings are specific to GNOME, such as the requirement to
	# fix the button mapping on the low-end Bamboo/Intuos tablets (see
	# http://sourceforge.net/p/linuxwacom/bugs/244/)

	P["Wacom Graphire4 4x5 Pad pad"]="
	Button 8 button 1
	Button 9 button 2
	"

	P["Wacom Bamboo 16FG 6x8 Pad pad"]="
	Button 1 button 1
	Button 3 button 2
	Button 8 button 3
	Button 9 button 4
	"

	P["Wacom Intuos PT M Pad pad"]="
	Button 1 button 1
	Button 3 button 2
	Button 8 button 3
	Button 9 button 4
	"
else
	# Some settings (e.g. display mapping) are already handled by
	# GNOME and only need to be set if we're running a different
	# desktop environment.

	P["Wacom Cintiq 24HD touch Finger touch"]="
	MapToOutput DVI-0
	"
	
	P["Wacom Cintiq 24HD touch Pen stylus"]="
	MapToOutput DVI-0
	"	
fi

########################################################################
# DO NOT EDIT BELOW THIS POINT
########################################################################

################
# Reads lines of input from stdin and filters out anything which is not 
# a hotplug event for an input device. This expects to be fed with input 
# from 'udevadm monitor'.
#####
filter_hotplugged_input_devices() {
	while read -r LINE; do
		echo "${LINE}" | grep -q "add"
		if [ $? -ne 0 ]; then
			>&2 echo "Device change noticed, but ignored (not an \"add\")"
			continue
		fi
		EVENT=$(echo "${LINE}" | grep -Eo "event[0-9]+")
		if [ x"$EVENT" == "x" ]; then
			continue
		fi
		>&2 echo "New input device hotplugged: $EVENT"
		echo "/dev/input/$EVENT"
	done
}

################
# Reads lines of input that contain device files and attempts to locate 
# the xinput device IDs that correspond to them. If a provided device 
# file is not used for any X devices, nothing will be output. If a 
# device is used by multiple X devices, multiple lines will be printed, 
# one for each X device.
#####
devicenames_to_xinput_ids() {
	while read DEVICE; do
		>&2 echo "Determining what Xinput devices use $DEVICE"
		for ID in $(xinput list --id-only); do
			if $(xinput list-props $ID | grep -q \""$DEVICE\""); then
				NAME=$(xinput --list --name-only $ID)
				>&2 echo "Xinput device $ID ($NAME) uses $DEVICE"
				echo $ID;
			fi
		done
	done
}

################
# Reads lines of input that contain X device IDs and filters out any 
# that are not under the control of the 'wacom' driver.
#####
filter_wacom_xinput_ids() {
	while read ID; do 
		xinput list-props $ID | grep -q "Wacom Debug Levels"
		if [ $? -ne 0 ]; then
			>&2 echo "Ignoring Xinput device $ID since it is not handled by the wacom driver"
			continue
		fi
		>&2 echo "Xinput device $ID appears to be handled by wacom driver"
		echo $ID
	done
}

################
# Reads lines of input that contain X device IDs of wacom devices and 
# uses xsetwacom to apply configurations that may exist for a device 
# which shares the same name.
#####
configure_wacom_devices() {
	while read ID; do
		NAME=$(xinput --list --name-only $ID)
		if [ x"${P[$NAME]}" == x ]; then
			>&2 echo "No configuration found for $NAME"
			continue
		fi
		
		while read -r PREFERENCE; do
			if [ x"$PREFERENCE" == "x" ]; then
				continue
			fi;
			CMD="xsetwacom set \"$NAME\" $PREFERENCE"
			echo "Running \`$CMD\`"
			eval $CMD
		done < <(echo "${P[$NAME]}")
	done
}

cat <(ls /dev/input/event*)           \
    <(stdbuf -oL udevadm monitor -u -s input | filter_hotplugged_input_devices) | \
  devicenames_to_xinput_ids           | \
  filter_wacom_xinput_ids             | \
  configure_wacom_devices