tn()
{
  local verbose=0
  local raw=0
  if [ "$1" = "-v" ]; then
    verbose=1
    shift
  elif [ "$1" = "-w" ]; then
    raw=1
    shift
  fi

  if [ ! -f $1 ]; then
    echo "invalid filename: $1"
    return 1
  fi

  local filename=$1; shift
  local basename=`basename $filename|sed -e 's,^\(.*\)\.\(.*\)$,\1,'`
  local filetype=`basename $filename|sed -e 's,^\(.*\)\.\(.*\)$,\2,'`
  local newfile="$basename.tn.$filetype"
  local tmpfile="/tmp/.tn.$USER.$$"
  local alt=$1; shift
  local pos=$1; shift

  local args="-filter Cubic -verbose -sample 100x100"
  case $filetype in
    gif)
      args="-negate -transparency black colors 16 $args -compress None";;

    jpg)
      args="$args -compress JPEG"
  esac

  convert $args $filename $newfile &> $tmpfile

	if [ $? != 0 ]; then
		echo "conversion failed."
		cat $tmpfile
		return 1
	fi

  local tout=`grep ".tn" $tmpfile`
  local geo=`echo $tout | cut -d" " -f2`
  local igeo=`echo $geo | cut -d"=" -f1`
  local tgeo=`echo $geo | cut -d">" -f2`
  local iwidth=`echo $igeo | cut -d"x" -f1`
  local iheight=`echo $igeo | cut -d"x" -f2`
  local twidth=`echo $tgeo | cut -d"x" -f1`
  local theight=`echo $tgeo | cut -d"x" -f2`

  local isize=`grep -v ".tn" $tmpfile | cut -d" " -f4`
  local tsize=""
  local tcolors=""
  case $filetype in
    gif)
      tsize=`echo $tout | cut -d" " -f5`
      tcolors=`echo $tout | cut -d" " -f4 | cut -dc -f1`;;

    jpg)
      tsize=`echo $tout | cut -d" " -f4`
      tcolors="16m";;

  esac

  rm -f $tmpfile

  if [ "$alt" = "left" -o "$alt" = "right" -o "$alt" = "center" ]; then
    pos=$alt
    alt=""
  fi

  if [ "x$alt" = "x" ]; then
    alt="$filename ($igeo, $isize)"
  fi

  if [ $verbose != 0 ]; then
    echo ""
    echo "read image $basename ($filetype, $igeo, $isize)."
    echo "wrote thumbnail $newfile ($tgeo, $tsize)."
    echo ""
    echo ""

    echo "asp image tag:"
    echo ""
  fi

  if [ $raw = 0 ]; then
    echo "<%"
    echo "  Call showImage(\"$basename\", \"$filetype\", \"$filetype\", _"
    echo "    $twidth, $theight, $iwidth, $iheight, _"
    echo "    \"$alt\", \"$pos\")"
    echo "%>"
  else
    echo "$basename;$filetype;$filetype;$twidth;$theight;$iwidth;$iheight;$alt;$pos"
  fi
}