#!/bin/sh

SC_DIR=scaled
WIDTH=1024
HEIGHT=768

usage()
{
    echo "usage: $(basename $0) [width height]" >&2
    exit 1
}

if [ $# -ne 0 ]; then
    [ $# -lt 2 ] && usage
    WIDTH=$1; HEIGHT=$2
fi

[ -d $SC_DIR ] || mkdir $SC_DIR || exit 1

tmpfile=$(mktemp ~/.$(basename $0).XXXXXX) || exit 1

infocmd=$(which pnmfile 2>/dev/null) || \
    { echo "Can't find \`pnmfile'" >&2; exit 1; }
scalecmd="$(which pnmscale 2>/dev/null) -xysize $WIDTH $HEIGHT $tmpfile" || \
    { echo "Can't find \`pnmscale'" >&2; exit 1; }

{ { j2p=$(which djpeg 2>/dev/null) || j2p=$(which jpegtopnm 2>/dev/null); } && \
    { p2j="$(which cjpeg 2>/dev/null) -quality 95" || \
    p2j="$(which pnmtojpeg 2>/dev/null) --quality=95"; }; } || \
    { echo "No JPEG support" >&2; j2p=; }
{ t2p=$(which tifftopnm 2>/dev/null) && p2t=$(which pnmtotiff 2>/dev/null); } \
    || { echo "No TIFF support" >&2; t2p=; }
{ { g2p=$(which giftopnm 2>/dev/null) || g2p=$(which giftoppm 2>/dev/null); } \
    && p2g=$(which ppmtogif 2>/dev/null) && \
    quantcmd="$(which ppmquant 2>/dev/null) 256"; } || \
    { echo "No GIF support" >&2; g2p=; }

exec 2>/dev/null

for f in *; do
    [ -f "$f" ] || continue
    case "$f" in
    *.[Jj][Pp][Gg] | *.[Jj][Pp][Ee][Gg])
	cmd=$j2p;;
    *.[Tt][Ii][Ff] | *.[Tt][Ii][Ff][Ff])
	cmd=$t2p;;
    *.[Gg][Ii][Ff])
	cmd=$g2p;;
    *)
	continue;;
    esac
    [ -n "$cmd" ] || continue
    $cmd "$f" >$tmpfile || continue
    res=$($infocmd $tmpfile | awk '{print $4 " " $6}') || continue
    xres=${res% *}; yres=${res#* }
    [ $xres -le $WIDTH -a $yres -le $HEIGHT ] && { cp $f $SC_DIR; continue; }
    case "$cmd" in
    $j2p)
	$scalecmd | $p2j >"$SC_DIR/$f";;
    $t2p)
	$scalecmd | $p2t >"$SC_DIR/$f";;
    $g2p)
	$scalecmd | $quantcmd | $p2g >"$SC_DIR/$f";;
    esac
done

rm -f $tmpfile
.