#! /bin/sh

## Example: reduire_images 1024 *.jpg
## -> Reduce the image so that neither side exceeds 1024px

if [ -z "$1" ]; then
    echo "Usage: $0 <size> <file> [<file> [...]]" >&2
    exit 1
fi
size="$1"
shift

old_weight=`du -ch "$@" 2>/dev/null | tail -n 1 | sed 's/	.*//'`
count=`ls "$@" 2>/dev/null | wc -l`
echo "Limiting size of $count images to ${size}x${size}..."
for file in "$@"; do
    if [ -r "$file" ]; then
        orig_size=`identify -format "%wx%h" "$file"`
        echo -n "$file: $orig_size ..."
        convert -geometry ${size}x${size} "$file" "$file"
        echo -n "\b\b\b"
        identify -format "-> %wx%h" "$file"
    else
        echo "W: Not converting '$file': unable to read" >&2
    fi
done
weight=`du -ch "$@" 2>/dev/null | tail -n 1 | sed 's/	.*//'`
echo "Weight of $count images: $old_weight -> $weight"