ImageMagick Image Merger

imagecomp.sh

#!/bin/sh

# IMAGE COMPOSITOR
# Author: Donald L. Merand
# Description: Merge images in a directory together into one composite image.
#   Be careful, this program is recursive and can eat up some disk space
#   creating images in subdirectories.

# default program options
RESULTSDIR="_results"
DIMENSIONS="640" 
EXTENSION="png"
# conversion options
BLEND=50
COMPOSITE=$(which composite)


# help message
function usage {
  #pass a message if you want
  [ ! -z "$1" ] && echo "$1\n"
  cat << USAGE
Usage: imagecomp <options> image_dir
Options:
  -d – Results directory (default _results)
  -s – Result image size (default 640x640)
  -e – Result image type (default png)
USAGE
}


#get command line params
while getopts ":hd:s:e:" OPTNAME
do
  case "$OPTNAME" in
    "h")
      usage
      exit
      ;;
    "d")
      RESULTSDIR=$OPTARG
      ;;
    "s")
      DIMENSIONS=$OPTARG
      ;;
    "e")
      EXTENSION=$OPTARG
      ;;
    "?")
      echo "Unknown option $OPTARG"
      ;;
    ":")
      echo "No argument value for option $OPTARG"
      ;;
    *)
    # Should not occur
      echo "Unknown error while processing options"
      ;;
  esac
done

#now get the non-options, in this case `image_dir`
shift $(($OPTIND - 1))
DIR="$1"


# check passed parameters
if [ -z "$DIR" ]; then
  usage "Please choose a directory where images to composite are stored."
  exit 1
fi

if [ ! -d "$DIR" ]; then
  usage "Please make sure you're passing a directory with images, not just a file."
  exit 1
fi

if [ ! "$COMPOSITE" ]; then
  usage "Please install ImageMagick"
  exit 1
fi


# define image compositing as a reusable function
function composite {
  # expects only a directory of $EXENSION files as an input
  DIR="$1"

  #exit if no input parameter
  [ -z "$DIR" ] && exit 1
  
  #exit if current dir is empty or only has one file
  dir_count=$(ls "$DIR" | wc -l)
  if [ $dir_count -eq 0 -o $dir_count -eq 1 ]; then
    exit 1
  fi

  NEWIMAGEDIR="$DIR/$RESULTSDIR"
  #create the results directory if it doesn't exist already
  [ ! -d "$NEWIMAGEDIR" ] && mkdir "$NEWIMAGEDIR"

  #set our initial counter
  x=1

  #loop through the images and combine them
  for image in "$DIR"/{*.png,*.jpg,*.gif,*.tiff}; do
    if [ -e "$image" ]; then
      echo "adding $image to $NEWIMAGEDIR..."
      if [ $((x % 2)) -eq 1 ]; then
        prev_image="$image"
      else
        #if the result is a file, composite it in
        $COMPOSITE -strip -resize "$DIMENSIONS" -blend "$BLEND" "$image" "$prev_image" "$NEWIMAGEDIR/$x.$EXTENSION"
      fi
      x=$((x + 1))
    fi
  done

  #now recurse...
  composite "$NEWIMAGEDIR"
}

#now run the actual image compositing
composite "$DIR"