#!/bin/bash


while test $# -gt 0; do
    DO_SHIFT=:
    case "$1" in
        "-i" )
            shift
            INFILE="$1"
            ;;
        "-o" )
            shift
            OUTFILE="$1"
            ;;
        "-f" )
            shift
            FRAME_ARG=$1
            ;;
        "-b" )
            shift
            BORDER_ARG=$1
            ;;
    esac
    $DO_SHIFT && shift
done
 
if [[ -n "$FRAME_ARG" ]]; then
    FRAME="-frame $FRAME_ARG"
    frame=${FRAME_ARG/x*}
else
    frame=0
fi

if [[ -n "$BORDER_ARG" ]]; then
    BORDER="-bordercolor '#6E6E6E' -border $BORDER_ARG"
    border=${BORDER_ARG/x*}
else
    border=0
fi

tsize=$(( 640 - frame - (border * 2) ))

convert  -size 640x480 "$INFILE" -bordercolor '#6E6E6E' \
$FRAME -thumbnail ${tsize}\> xc:black +swap -gravity center \
-composite "$OUTFILE"