generate-wallpaper-xml

#!/bin/bash
#=======================================================================================================================
# Description
#   Script to generate an XML file for wallpaper rotation in Gnome 3/Unity. See
#   https://yktoo.com/en/blog/post/2012/11/17-ubuntu/gnome-3-xml-wallpaper-creation/ for details.
# Synopsis
#   generate-wallpaper-xml [options] <pictures_dir> <xml_file>
# Author
#   Dmitry Kann, https://yktoo.com/
# License
#   Public domain
#=======================================================================================================================

. "$(dirname "$(realpath "$0")")/common.sh"

# Setup vars
def_duration_static=1795
def_duration_transition=5

USAGE_INFO="XML wallpaper list generation script. Written by Dmitry Kann, https://yktoo.com/

Usage: $0 [options] pictures_dir xml_file

Options:
  -d <number> Override default display duration ($def_duration_static seconds)
  -s <mode>   Sort the files according to <mode>, whose values are:
     name     Sort by file path and name
     shuffle  Randomize file order
  -t <number> Override default transition duration ($def_duration_transition
              seconds). If 0, no transition is used
  -v          Verbose output
  -w          Set the generated XML file as current wallpaper

pictures_dir  Path to directory with pictures

xml_file      Path to the output XML file"

#-----------------------------------------------------------------------------------------------------------------------

# Parse the command line
typeset -i duration_static=$def_duration_static
typeset -i duration_transition=$def_duration_transition
b_set_wallpaper=0
b_verbose=0
sort_command='cat'

args=$(getopt -o d:s:t:vw -- "$@")
[ $? -eq 0 ] || usage
eval set -- $args
for i; do
    case "$i" in
        -d)
            duration_static=$2
            [[ "$duration_static" -le 0 ]] && usage "Display duration should be greater than zero"
            ;;

        -s)
            case $2 in
                name)
                    sort_command="sort"
                    ;;
                shuffle)
                    sort_command="shuf"
                    ;;
                *)
                    usage "Invalid sort mode: $2"
                    ;;
            esac
            ;;

        -t)
            [[ -z "$2" ]] && usage "Transition duration not specified"
            duration_transition=$2
            ;;

        -v)
            b_verbose=1
            ;;

        -w)
            b_set_wallpaper=1
            ;;

        --)
            shift
            break
            ;;
    esac
    shift
done

# Check the parameters
dir_wallpapers="$1"
file_output_xml="$2"
[[ -z "$dir_wallpapers"  ]] && usage "No wallpaper directory specified"
[[ -d "$dir_wallpapers"  ]] || err "Directory $dir_wallpapers does not exist"
[[ -z "$file_output_xml" ]] && usage "No output XML file specified"

# Verbose output
if [[ $b_verbose -ne 0 ]]; then
    log "Display duration: $duration_static sec"
    log "Transition duration: $duration_transition sec"
fi

# Canonicalize directory and output file name (make it absolute)
dir_wallpapers="$(realpath "$dir_wallpapers")"
file_output_xml="$(realpath "$file_output_xml")"

# Write XML file header
cat << EOF >"$file_output_xml"
<background>
    <!-- Wallpaper definition file. Generated on $(date) by $0 -->
    <starttime>
        <year>2000</year>
        <month>01</month>
        <day>01</day>
        <hour>00</hour>
        <minute>00</minute>
        <second>00</second>
    </starttime>
EOF

# Iterate through image files
unset last_img_file
i_count=0
while read img_file; do
    # Insert transition statement if it's not the first image
    if [[ -n "$last_img_file" && "$duration_transition" -gt 0 ]]; then
        cat << EOF >>"$file_output_xml"
<transition>
    <duration>$duration_transition</duration>
    <from>$last_img_file</from>
    <to>$img_file</to>
</transition>
EOF
    fi

    # Insert 'static' image statement
    cat << EOF >>"$file_output_xml"
<static>
    <duration>$duration_static</duration>
    <file>$img_file</file>
</static>
EOF
    last_img_file="$img_file"
    ((i_count++))
    # Trick below to avoid piping that would limit the scope of $i_count to the subshell
done << EOF
$(find "$dir_wallpapers" -type f \( -iname '*.jpeg' -o -iname '*.jpg' -o -iname '*.png' \) -print | $sort_command)
EOF

# Verbose output
[[ $b_verbose -ne 0 ]] && log "File $file_output_xml generated; $i_count wallpaper files found"

# Write XML file footer
echo '</background>' >>"$file_output_xml"

# Set wallpaper file as current, if needed
if [[ $b_set_wallpaper -ne 0 ]]; then
    gsettings set org.gnome.desktop.background picture-uri "file://$file_output_xml" &&
    gsettings set org.gnome.desktop.background picture-options "zoom" &&
    # Verbose output
    ( [[ $b_verbose -ne 0 ]] && log "Wallpaper URI set to file://$file_output_xml" )
fi