djcev.com

#!/bin/sh
#
#  Copyright (c) 2015-2021 Cameron Vanderzanden. Available under the
#  terms of the 2-clause BSD license. Please see the file "LICENSE" in
#  the root dir of this repository for more information.
#
#- back.sh 2015/01/13 cev, last updated 2021/12/07
## Usage: back.sh [-acfhtvV] [-d directory] [-m method] wallpaper...
##  
##     Set wallpaper (xorg 'root window' image). If no wallpaper is specified,
##     select one at random from [-d directory]. If more than one file is
##     specified, select one at random.
## 
##     This script is a frontend to hsetroot (or, alternately, pcmanfm-qt).
##     hsetroot can be found at https://github.com/himdel/hsetroot .
##  
##       -a     Set maximized wallpaper, preserving aspect. (default)
##       -c     Set centered wallpaper.
##       -d     Directory to select an image at random from.
##       -f     Set fullscreen wallpaper.
##       -h     Show help.
##       -m     Background setter method. Valid methods: hsetroot, pcmanfm.
##       -t     Set tiled wallpaper.
##       -v     Be verbose.
##       -V     Print version info.
##  
#  Useful notes: 
#  http://www.linuxforums.org/forum/programming-scripting/ \
#      121380-random-file-folder-sub-folders.html

[ -x $HOME/.local/bin/cev_print.sh ] && . $HOME/.local/bin/cev_print.sh

self="${0##*'/'}"
action='aspect'
bgdir="$HOME/Pictures/Wallpapers"
method="dconf-mate"

cleanup() {
    if [ "$tfile" -a -r "$tfile" ]; then rm "$tfile"; fi
}

die_invalid_method() {
    print_self error
    printf "%binvalid method %b%s%b\n" "$_norm" "$_error" "$1" "$_clear" >&2
    exit 1
}

die_no_dir() {
    print_directorynotfound "$1"
    exit 1
}

die_no_papers() {
    print_self error
    printf "%bno papers found%b\n" "$_norm" "$_clear" 1>&2
    exit 1
}

die_no_x() {
    print_self error
    printf "%bDISPLAY%b not set. Is X running?%b\n" \
        "$_error" "$_norm" "$_clear" >&2
    exit 1
}

randwall() {
    # max for rng; exit if zero.
    max="$(wc -l $1)"
    max=${max%' '*}
    [ $max -lt 1 ] && die_no_papers
    # random number within 1-$max
    if [ -x "$(which jot)" ]; then
        n=$(jot -r 1 1 $max)            # BSD
    elif [ -x "$(which shuf)" ]; then
        n=$(shuf -i 1-$max -n 1)        # GNU
    else
        # this really doesn't work. awk rand() seems to be the problem.
        etime=$(date -j -f "%a %b %d %T %Z %Y" "`date`" "+%s")
        r=$(awk "BEGIN {srand($etime); print rand()}")
        n=$(expr ${r##*.} % $max)
        unset etime && unset r
    fi
    sed -n "${n}p" $1
}

setbg() {
    # next section is based on work from an old copy of awsetbg by
    # Han Boetes & Julien Danjou, see:
    # https://github.com/awesomeWM/awesome/blob/ \
    #     2853d58f52cfbc4515fad7f45875d5cd31b1085e/utils/awsetbg
    case $method in
        dconf-mate)
            setter="$(which dconf) write "
            setter="$setter /org/mate/desktop/background/picture-filename"
            aspect=""
            center=""
            full=""
            tile=""
            namepre="'"
            namepost="'"
            ;;
        hsetroot)
            setter="$(which hsetroot)"
            aspect="-full"
            center="-center"
            full="-fill"
            tile="-tile"
            namepre=""
            namepost=""
            ;;
        pcmanfm)
            setter="$(which pcmanfm-qt) --set-wallpaper"
            aspect=""
            center=""
            full=""
            tile=""
            namepre=""
            namepost=""
            ;;
        wmsetbg)
            setter="$(which wmsetbg)"
            aspect="-b black -a -S"
            center="-b black -e"
            full="-s -S"
            tile="-t"
            namepre=""
            namepost=""
            ;;
        *) die_invalid_method "$method" ;;
    esac
    
    if [ "$verbose" ]; then
        print_self
        printf "wallpaper name %s\n" "$@"
        $setter $(eval echo \$${action}) "$namepre""$@""$namepost"
    else
        $setter $(eval echo \$${action}) \
            "$namepre""$@""$namepost" 1>/dev/null 2>&1
    fi
}

[ -z "$DISPLAY" ] && die_no_x

while getopts "acd:fhm:tvV?" option; do
    case $option in
        a) action='aspect' ;;
        c) action='center' ;;
        d) bgdir="$OPTARG" ;;
        f) action='full' ;;
        h) print_help && exit ;;
        m) method="$OPTARG" ;;
        t) action='tile' ;;
        v) verbose='true' ;;
        V) print_version && exit ;;
        "?") print_help && exit ;;
    esac
    shift $((OPTIND - 1))
done

trap cleanup EXIT

if [ $# -lt 1 ]; then
    # no file specified. select a random file from $bgdir.
    [ ! -d "$bgdir" ] && die_no_dir "$bgdir"
    tfile=$(mktemp ${TMPDIR:-/tmp}/${self}.XXXXXXXX)
    find "$bgdir" -type f >>$tfile
    find "$bgdir" -type l >>$tfile
    wallpaper="$(randwall $tfile)"
    rm $tfile
elif [ $# -gt 1 ]; then
    # more than one file specified. select one at random.
    tfile=$(mktemp ${TMPDIR:-/tmp}/${self}.XXXXXXXX)
    for wall in $@; do printf "%s\n" "$wall" >>$tfile; done
    wallpaper="$(randwall $tfile)"
    rm $tfile
else
    # exactly one argument
    wallpaper="$@"
fi

setbg "$wallpaper"