Set wallpaper independently for each tag in herbstluftwm

wallpaper.sh

#!/bin/bash

# This code was modified from Thorsten by me:
# https://bbs.archlinux.org/viewtopic.php?pid=1024618#p1024618

# sets a tag defined wallpaper when tag changes
declare -A WALLPAPER

# These wallpapers come with Deepin desktop environment, but also look great in hlwm
DIR=/usr/share/backgrounds
WALLPAPER=(
    # first wallpaper will be the fallback wallpaper
    [0]=$DIR/Autumn_in_Kanas_by_Wang_Jinyu.jpg
    [file]=$DIR/Reflection_of_the_Kanas_Lake_by_Wang_Jinyu.jpg
    [edit]=$DIR/Ocean_by_Shu_Le.jpg
    [read]=$DIR/Scenery_in_Plateau_by_Arto_Marttinen.jpg
    [browse]=$DIR/Sunrise_by_Alexandre_Godreau.jpg
    [draw]=$DIR/Overlooking_of_the_Coastal_by_Alex_Siale.jpg
    [watch]=$DIR/Maple_Leaf_by_Aaron_Burden.jpg
    [hear]=$DIR/Dew_by_Aaron_Burden.jpg
    [mail]=$DIR/Hummingbird_by_Shu_Le.jpg
    [chat]=$DIR/Sunset_of_the_Lake_Nam_by_Wang_Jinyu.jpg
)


# it should (hopefully) die on reload
herbstclient --idle '(tag_changed|reload)' \
    | while read line ; do
    ARGS=( $line )
    HOOK=${ARGS[0]}
    TAG=${ARGS[1]}
    case $HOOK in
	reload)
	    exit 1
	    ;;
	quit_panel)
	    exit 1
	    ;;
	tag_changed)
	    if ! [ -z "${WALLPAPER[$TAG]}" ] ; then
		# there is a wallpaper for this tag
		CUR=${WALLPAPER[$TAG]}
	    else
		# there is no wallpaper for this tag -> fall back
		CUR=${WALLPAPER[0]}
	    fi
	    echo "setting wallpaper to $CUR"
	    feh --bg-scale $CUR
	    ;;
	*) ;;
    esac
done