posix-compatible function definitions

jailbaitredditwallpaper.sh

#!/bin/bash
#
# fetches the first found image from $REDDIT_RSS subthread $SUB,
#+ converts it to your desktop size
#+ and sets it as wallpaper

# subreddit
SUB="jailbait"

# reddit rss-uri
REDDIT_RSS="http://www.reddit.com/r/"$SUB"/.rss"

WORKFOLDER="/home/syranez/Pictures/bg"

# convert the image to this size
IMAGE_SIZE="1680x1050"

# checks dependencies
#+
#+ @return 1: missing dependencies
#+ @return 0: all ok
check () {

    if [ -z `which wget` ]; then
        return 1
    fi

    if [ -z `which awsetbg` ]; then
        return 1
    fi

    return 0
}

# prepares $WORKFOLDER
#+
#+ @param workfolder
prepare () {

    if ! [ -f "$1" ]; then
        mkdir -p "$1";
    fi
}

# gets something from the internet
#+
#+ @param source
#+ @param target
iget () {

    wget -q "$1" -O "$2"
}

# exracts the image uri from the feed
#+
getimageuri () {

    IMAGEURI=`iget "$REDDIT_RSS" - | sed 's/i.img/\n&/g' | head -2 | tail -1 | cut -d "&" -f1 | sed 's/./http:\/\/&/'`
}

# fetches the image
#+
getimage () {

    getimageuri

    iget "$IMAGEURI" "$WORKFOLDER/jb.jpg"
}

# converts the image in other sizes
#+
#+ @param local image uri
convert () {

    TEMP="$WORKFOLDER/jb_tmp.jpg"
    cp "$1" "$TEMP"
    mogrify -modulate 25,0,100 -quality 96 "$TEMP"
    mogrify -resize 2560x -quality 96 "$TEMP"
    mogrify -crop "$IMAGESIZE"+640+512 -quality 96 "$TEMP"
    mogrify -blur 128 -quality 96 "$TEMP"
    mogrify -resize 300x -quality 94 "$TEMP"
    mogrify -bordercolor white -border 10 "$TEMP"
#    composite -gravity center "$1" "$TEMP" "$TEMP"

    cp "$TEMP" "$1"
}

# sets the image as wallpaper
#
#+ @param local image uri
setwallpaper () {

    awsetbg -f "$1"
}

check
if [ "$?" -eq "2" ]; then
    exit 1
fi

prepare "$WORKFOLDER"
getimage
convert "$WORKFOLDER/jb.jpg"
setwallpaper "$WORKFOLDER/jb.jpg"