Bash script to loop random wallpaper for current desktop

randomwallpaper

#!/bin/bash
## Untitled Random Wallpaper Slideshow Script. Name is subject to change.
## Edit 2016/06/17 00:23 UTC+8

#### Variables ####
# Initialize variables with default values
OPTIND=1
rwp_sleep_time_def=1m
rwp_cfg_file_set=0
rwp_handler=auto

rwp_handlers_list="Available wallpaper handlers: mate, gnome, xfce, lxde, pcmanfm, cinnamon, feh"

# Get XDG_PICTURES_DIR from .config/user-dirs.dirs. Ex:"$HOME/Pictures"
export $(cat $HOME/.config/user-dirs.dirs | grep PICTURES)
# Cut from " to /.  Ex:"$HOME/Picures" -> Pictures"
XDG_PICTURES_DIR=$(echo ${XDG_PICTURES_DIR#\"*/})
# Cut off the last ". Ex: Pictures" -> Pictures
XDG_PICTURES_DIR=$(echo ${XDG_PICTURES_DIR%\"})
# Ex. Pictures -> /home/user/Pictures/Wallpapers
rwp_dir=$HOME/$XDG_PICTURES_DIR/Wallpapers

# Use .rwp.cfg if it exists
if [[ -f $HOME/.rwp.cfg ]]; then
  rwp_cfg_file_set=1
  rwp_cfg=$HOME/.rwp.cfg
else
  touch $HOME/.rwp.cfg
  rwp_cfg_file_set=1
fi

# Handle Options
while getopts "h?t:d:c:w:l" rwp_opt; do
  case "$rwp_opt" in
  h|\?)
      echo "
Usage: randomwallpaper [OPTIONS]

Options:
 -t <time>                Set global wait time (default:1m)
 -d <DIR>                 Set wallpaper directory (default:$HOME/$XDG_PICTURES_DIR/Wallpapers)
 -c <config file>         Use config file to set wait time for individual images
 -w <wallpaper handler>   Set wallpaper handler manually (default:auto)
 -l                       List all wallpaper handlers
 -h or -?                 Show help (this message)
"
      exit 0
    ;;
  t)
    rwp_sleep_time_def=$OPTARG
    ;;
  d)
    rwp_dir=$OPTARG
    ;;
  c)
    rwp_cfg=$OPTARG
    rwp_cfg_file_set=1
    ;;
  w)
    case $OPTARG in
    MATE|mate)
        rwp_handler=mate
        ;;
    GNOME|gnome)
        rwp_handler=gnome
        ;;
    XFCE|xfce)
        rwp_handler=xfce
        ;;
    LXDE|lxde)
        rwp_handler=pcmanfm
        rwp_handler_display=LXDE
        ;;
    pcmanfm)
        rwp_handler=pcmanfm
        ;;
    Cinnamon|cinnamon)
        rwp_handler=cinnamon
        ;;
    feh)
        rwp_handler=feh
        ;;
    *)
        echo $rwp_handlers_list
        exit 1
    esac
    ;;
  l)
    echo $rwp_handlers_list
    exit 0
  esac
done

rwp_files=($rwp_dir/*)

# Report result
echo "rwp_sleep_time_def is $rwp_sleep_time_def"
echo "rwp_dir is $rwp_dir"
echo "rwp_cfg is $rwp_cfg"

#~~~ Variables ~~~#


#### Functions ####

# Main Loop
# rwp_loop <WP handler>
rwp_loop () {
  
  while :; do
    # Rescan file list
    rwp_files=($rwp_dir/*)
    # Randomly select a file
    rwp_wallpaper=$(printf "%s\n" "${rwp_files[RANDOM % ${#rwp_files[@]}]}")
    
    # Read rwp_sleep_time only when config file is set
    if [[ $rwp_cfg_file_set == 1 ]]; then
      # Read cfg file
      while read -r line; do
        if echo $rwp_wallpaper | grep ${line%\ *}; then  # if rwp_wallpaper is in the cfg
          rwp_sleep_time=${line#*\ }  # set rwp_sleep_time to that defined in the cfg
          rwp_cfg_used=1
          echo rwp_sleep_time for this image is $rwp_sleep_time
          break
        else
          rwp_cfg_used=0
        fi
      done < $rwp_cfg
    fi

    # Use default rwp_sleep_time
    if [[ $rwp_cfg_used == 0 || $rwp_cfg_file_set == 0 ]]; then
      rwp_sleep_time=$rwp_sleep_time_def
      echo rwp_sleep_time for this image is not specified in config
    fi
    
    # using variable as input needs "" to handle spaces correctly
    rwp_set_$1 "$rwp_wallpaper"
    sleep $rwp_sleep_time
  done
}


rwp_detect () {
# Detect DE in use and start loops

# MATE
  if [[
  $XDG_CURRENT_DESKTOP == "MATE" ||
  $XDG_CURRENT_DESKTOP == "mate" ]]; then
    rwp_handler=mate

# Budgie
  elif [[
  $XDG_SESSION_DESKTOP == "budgie-desktop" ||
  $DESKTOP_SESSION == "budgie-desktop" ||
  $GDMSESSION == "budgie-desktop" ]]; then
    rwp_handler=gnome
    rwp_handler_display=Budgie

# GNOME & Cinnamon
  elif [[
  $XDG_CURRENT_DESKTOP == "GNOME" ||
  $XDG_CURRENT_DESKTOP == "gnome" ]]; then
    if [[ $GDMSESSION == "cinnamon" ]]; then
      rwp_handler=cinnamon
    else
      rwp_handler=gnome
    fi

# Cinnamon
  elif [[ $XDG_CURRENT_DESKTOP == "X-Cinnamon" ]]; then
    rwp_handler=cinnamon

# Unity
  elif [[ $XDG_CURRENT_DESKTOP == "Unity" ]]; then
    if [[ -z ${MIR_SERVER_NAME+x} ]]; then # Check if Mir is in use
      rwp_handler=gnome # It's not
      rwp_handler_display=Unity
    else
      rwp_exit "Unity with Mir" # It is
    fi

# XFCE
  elif [[ $XDG_CURRENT_DESKTOP == "XFCE" ]]; then
    rwp_handler=xfce

# LXDE
  elif [[ $XDG_CURRENT_DESKTOP == "LXDE" ]]; then
    rwp_handler=lxde
    rwp_handler_display=LXDE

# KDE
  elif [[ $GDMSESSION == "plasma_desktop" ]]; then
    rwp_exit "KDE Plasma"

# feh ??
# elif killall -q -0 feh; then
#  rwp_handler=feh

# Other
  else
    rwp_exit "Desktop in use"
  fi
}

rwp_set_mate () {
  gsettings set org.mate.background picture-filename "$1"
}

rwp_set_gnome () {
  gsettings set org.gnome.desktop.background picture-uri "file://$1"
}

rwp_set_cinnamon () {
  gsettings set org.cinnamon.desktop.background picture-uri "file://$1"
}

rwp_set_feh () {
  feh --bg-scale "$1"
}

rwp_set_pcmanfm () {
  pcmanfm --set-wallpaper "$1"
}

rwp_set_xfce () {
  rwp_set_xfce_wspc=$(($(xfconf-query -c xfwm4 -p /general/workspace_count)-1))
  for ((i=rwp_set_xfce_wspc; i>=0; i--)); do
    xfconf-query -c xfce4-desktop -p /backdrop/screen0/monitor0/workspace$i/last-image -s "$1"
  done
}

rwp_exit () {
  echo "$1 is not supported"
  exit 1
}

#~~~ Functions ~~~#


#### Main Logic ####

if [[ $rwp_handler == auto ]]; then
  # Detect Desktop
  rwp_detect # will set rwp_handler according to environment variables

  if [[ -z ${rwp_handler_display+x} ]]; then # Check for rwp_handler_display
    echo "Looping random wallpaper for: $rwp_handler" # it does not exist
  else
    echo "Looping random wallpaper for: $rwp_handler_display" # it exists
  fi

  rwp_loop $rwp_handler
else # when rwp_handler is set
  echo "Looping random wallpaper for: $rwp_handler"
  rwp_loop $rwp_handler
fi

#~~~ Main Logic ~~~#

# Main Logic is not a function because we'll never call it.