#!/bin/sh

rootdir="."
background_file_name="background.jpg"

if [ $# -eq 2 ]; then
    rootdir=$1
    background_file_name=$2
elif [ $# -eq 1 ]; then
    rootdir="."
    background_file_name=$1
fi

find "$rootdir" -type d | while read pngdir; do
    if [ -f "$pngdir/$background_file_name" ];
    then
    echo "Background file found in $pngdir/$background_file_name"

    find "$pngdir" -name *.png -maxdepth 1 | while read foreground_file; do
        echo "processing $foreground_file with $pngdir/$background_file_name"
        mkdir -p "$pngdir/merged"
        ./composite -gravity center -compress Lossless "$foreground_file" "$pngdir/$background_file_name" "$pngdir/merged/`basename -s .png \"$foreground_file\"`.jpg"
    done
    fi
done