Bash script for watermarking with imagemagick

watermark.bash

#!/bin/bash
## This script uses the `convert` command from the imagemagick library to add a watermark to one or more images

WATERMARK= # add your default watermark here
WSIZE="20%"
WPADDING="0"
GRAVITY=SouthEast
OUTDIR=watermarked
DRYRUN=
VERBOSE=
POSITIONAL=()

if [[ $# -eq 0 ]]; then
	echo "usage: watermark [options] files"
	echo "options:"
	echo " -w --watermark $WATERMARK"
	echo " -ws --watermark-size $WSIZE"
	echo " -wp --watermark-padding $WPADDING"
	echo " -g --gravity $GRAVITY"
	echo " -o --outdir $OUTDIR"
	echo " -d --dry-run"
	echo " -v --verbose"
	exit 1
fi

while [[ $# -gt 0 ]]; do
  key="$1"

  case $key in
    -w|--watermark)
      WATERMARK="$2"
      shift # past argument
      shift # past value
      ;;
    -ws|--watermark-size)
      WSIZE="$2"
      shift # past argument
      shift # past value
      ;;
    -wp|--watermark-padding)
      WPADDING="$2"
      shift # past argument
      shift # past value
      ;;
    -g|--gravity)
      GRAVITY="$2"
      shift # past argument
      shift # past value
      ;;
    -o|--outdir)
      OUTDIR="$2"
      shift # past argument
      shift # past value
      ;;
    # -l|--lib)
    #   LIBPATH="$2"
    #   shift # past argument
    #   shift # past value
    #   ;;
    -d|--dry-run)
      DRYRUN=YES
      shift # past argument
      ;;
    -v|--verbose)
      VERBOSE=YES
      shift # past argument
      ;;
    *)    # unknown option
      POSITIONAL+=("$1") # save it in an array for later
      shift # past argument
      ;;
  esac
done

if [[ $VERBOSE ]]; then
	echo "outdir  = ${OUTDIR}"
	echo "watermark = ${WATERMARK}"
	echo "watermark size = ${WSIZE}"
	echo "watermark padding = ${WPADDING}"
	echo "dry run = ${DRYRUN}"
	echo "verbose = ${VERBOSE}"
fi

for INFILE in "${POSITIONAL[@]}"; do
	FN=`basename $INFILE`

	if [[ $DRYRUN || $VERBOSE ]]; then
		echo composite -quality 100 -gravity $GRAVITY -background none \\\( -resize ${WSIZE}x$WSIZE  "$WATERMARK" \\\) -geometry +$WPADDING+$WPADDING \"$INFILE\" \"${OUTDIR}/${FN}\"
	fi

	if [[ -z $DRYRUN ]]; then
		composite -quality 100 -gravity $GRAVITY -background none \( -resize ${WSIZE}x$WSIZE  "$WATERMARK" \) -geometry +$WPADDING+$WPADDING "$INFILE" "${OUTDIR}/${FN}"
	fi
done