#!/bin/sh
#
#  mksmallpic.sh [-d dir] [file ...]
#
#  Shrink large jpeg files to 640x480 pixels and
#  rotate them according to prefixes:
#    _l.jpg:  rotate 90 degrees left
#    _r.jpg:  rotate 90 degrees right
#    _ll.jpg: rotate 180 degrees
#  only when the large files are updated.
#

dir='..'

makefile=/tmp/picmake.$$


case $# in
0) files=*.jpg ;;
*) if [ $1 = "-d" ]; then
     dir=$2
     shift; shift
   fi
   files=$*
   ;;
esac


rm -f $makefile


for file in $files
do
    smallpic=$dir/s_${file}
    cat << EOF > $makefile
all:		$smallpic
$smallpic:		$file
	@if echo $file | egrep '_r.jpg'; then \
        djpeg $file | pnmrotate -90 | pnmscale -xy 640 640 | \
        cjpeg > $dir/s_${file} ; \
    elif echo $file | egrep '_l.jpg'; then \
        djpeg $file | pnmrotate +90 | pnmscale -xy 640 640 | \
        cjpeg > $dir/s_${file} ; \
    elif echo $file | egrep '_ll.jpg'; then \
        djpeg $file | pnmflip -r180 | pnmscale -xy 640 640 | \
        cjpeg > $dir/s_${file} ; \
    elif echo $file | egrep '\.jpg\$\$'; then \
        djpeg $file | pnmscale -xy 640 640 | \
        cjpeg > $dir/s_${file} ; \
    fi
EOF
    make -f $makefile
    rm -f $makefile
done