#!/bin/bash
# thumbnails -- create thumbnail images for the graphics file specified, 
#    matching exact dimensions or not-to-exceed dimensions#

convargs="-unsharp 0x.5 -resize"
count=0; exact=""; fit=""

usage()
{
  echo "Usage: $(basename $0) (-e|-f) thumbnail-size image [image] [image]" >&2
  echo "-e  resize to exact dimensions, ignoring original proportions" >&2
  echo "-f  fit image into specified dimensions, retaiing proportion" >&2 
  echo "-s  strip EXIF information (make ready for Web use)" >&2
  echo "    please use WIDTHxHEIGHT for requested size (e.g., 100x100)"
  exit 1
}

#############
## BEGIN MAIN

if [ $# -eq 0 ] ; then
  usage
fi

while getopts "e:f:s" opt; do
  case $opt in
   e ) exact="$OPTARG";                ;;
   f ) fit="$OPTARG";                  ;;
   s ) strip="-strip";		       ;;
   ? ) usage;			       ;;
  esac
done
shift $(($OPTIND - 1))  # eat all the parsed arguments

 rwidth="$(echo $exact $fit | cut -dx -f1)"	# requested width
rheight="$(echo $exact $fit | cut -dx -f2)"	#  ... and height

for image
do
  width="$(identify -format "%w" "$image")"
  height="$(identify -format "%h" "$image")"

  # Building thumbnail for image $image, width=$width and height=$height
  if [ $width -le $rwidth -a $height -le $rheight ] ; then
    echo "Image $image is already smaller than reqeusted dimensions. Skipped."
  else
    # build new filename 

    suffix="$(echo $image | rev | cut -d. -f1 | rev)"
    prefix="$(echo $image | rev | cut -d. -f2- | rev)"
    newname="$prefix-thumb.$suffix"
   
    # add the "!" suffix to ignore proportions as needed

    if [ -z "$fit" ] ; then
      size="$exact!"
      echo "Creating ${rwidth}x${rheight} (exact size) thumbnail for file $image"
    else
      size="$fit"
      echo "Creating ${rwidth}x${rheight} (max dimensions) thumbnail for file $image"
    fi

    convert "$image" $strip $convargs "$size" "$newname"
  fi
  count=$(( $count + 1 ))
done

if [ $count -eq 0 ] ; then
  echo "Warning: no images found to process."
fi

exit 0