ImageMagick: resize and watermark

copyright.sh

#!/usr/bin/env bash

export ROOT_DIR="/path/to/pics"

function userInput() {
  echo -e "Warning: I can only resize and watermark images in ${ROOT_DIR}.\n"
  read -p "What is the directory name in which to resize and watermark images? " DIR

  export INPUT_DIR="${ROOT_DIR}/${DIR}"
  cd ${ROOT_DIR}
  
  if [[ -z ${DIR} ]]; then
    userInput
  fi
  
  if [[ ! -d ${DIR} ]]; then
    echo -e "\nThis directory \"${DIR}\" doesn't exist. Please try again."
    exit 0
  fi
}

function createOutputDir() {
  OUTPUT_DIR="${INPUT_DIR}/OK"
  
  if [[ ! -d ${OUTPUT_DIR} ]]; then
    echo -e "\n> Creating directory \"OK\"..."
    mkdir "${OUTPUT_DIR}"
  else
    echo -e "\nThe directory \"OK\" already exists. Please delete it before you run this script."
    exit 0 
  fi
}

function resizeAndWatermarkImages() {
  MOGRIFY=$(command -v mogrify)
  SIZE="1399" # Assumes W:931px x H:1399px
  QUALITY="82"
  WATERMARK="© WhateverIwantToPutHere"
  COLOR="gray(40%)"
  FONT="liberation-sans"
  FONT_SIZE="42"
  GRAVITY="East"
  EXTENSION="jpg"
  
  echo "> Resizing images and adding the watermark..."
  
  ${MOGRIFY} -path "${OUTPUT_DIR}"/ \
    -filter Triangle \
    -define filter:support=2 \
    -resize ${SIZE} \
    -unsharp 0.25x0.08+8.3+0.045 \
    -dither None \
    -posterize 136 \
    -quality ${QUALITY} \
    -define jpeg:fancy-upsampling=off \
    -define png:compression-filter=5 \
    -define png:compression-level=9 \
    -define png:compression-strategy=1 \
    -define png:exclude-chunk=all \
    -interlace none \
    -colorspace sRGB \
    -draw "rotate -90 text 440,40 '${WATERMARK}'" \
    -fill "${COLOR}" \
    -font ${FONT} \
    -pointsize ${FONT_SIZE} \
    -gravity ${GRAVITY} \
    "${INPUT_DIR}"/*.${EXTENSION}
  
  echo -e "\nDone! Images are available in ${OUTPUT_DIR}"
}

userInput
createOutputDir
resizeAndWatermarkImages