#!/bin/bash
#
# Syntax:  mk_thumbnails [-h] [-w width] file [...]
#
# Purpose: Creates thumbnails for the given files using the convert
#          command. The output file names are of the form TN_file.
#          The default value for width is 100.
#          In fact, instead of the width you can also also specify a
#          geometry (like scale%, xheight, widthxheight etc.) as argument
#          of the -w flag.
#          The -h flag shows the help info for this command.

# Created: Jan  1, 2011       by Bart De Schutter
# Last revised:
#
# See http://www.deschutter.info/util/scripts.html for the latest version of
# this script.

# Status: public
# Category: images

# 
# Define default options
#
geometry="100"

# 
# Process options
#
while getopts :hw: option
do 
   case "$option" in
      h) sed '/^$/q;/^#!/d;s/^# //;s/^#//' $0 >&2
         exit 1;;
      w) geometry=$OPTARG;;
      :) echo >&2 
         echo >&2 "Option -$OPTARG requires an argument."
         echo >&2
         sed '/^$/q;/^#!/d;s/^# //;s/^#//' $0 >&2
         echo >&2
         exit 1;;
     \?) echo >&2 
         echo >&2 "Unknown option: $OPTARG"
         echo >&2
         sed '/^$/q;/^#!/d;s/^# //;s/^#//' $0 >&2
         exit 1;;
   esac
done
shift $(($OPTIND-1))

#
# Check whether there is any output argument present.
#
if [ $# -eq 0 ]
then
   echo >&2
   echo >&2 "ERROR: ${0##*/} requires at least 1 input argument."
   echo >&2
   sed '/^$/q;/^#!/d;s/^# //;s/^#//' $0 >&2
   exit 1
fi

#
# Process files.
#
for fil in "$@"
do
   convert -thumbnail "$geometry" "$fil" "TN_$fil"
   echo "$fil" processed
done