#! /bin/bash
# Last edited on 2004-01-09 13:09:21 by stolfi

cmd="${0##*/}"
usage="${cmd} DIR IMG... > MOVIE.gif"

# Reads the images "{IMG}.jpg" from directory {DIR}.  
# Converts them to 640x480 pixels, adjusts lighting,
# and turns them into a GIF movie that is written to stdout. 

if [ $# -lt 2 ]; then echo "usage: ${usage}"; exit 1; fi

dir="$1"; shift;
imgs=( $* )

temp="/tmp/$$"
bp=1
wp=5

n=100
frames=( )
for img in ${imgs[@]} ; do 
  frame=${temp}-${n}.ppm
  convert ${dir}/${img}.jpg -geometry 'x480' PPM:- \
    | ppmtorgb3
  for chn in red grn blu ; do 
    cat noname.${chn} \
      | pgmnorm -bpercent ${bp} -wpercent ${wp} \
      | pnmgamma 1.80 \
      | pnmdepth 255 \
      > ${temp}-${chn}.pgm
  done
  rgb3toppm ${temp}-{red,grn,blu}.pgm \
    > ${frame}
  display -title '%f' ${frame} ${temp}-{red,grn,blu}.pgm &
  frames=( ${frames[@]} ${frame} )
  n=$((n + 1))
done

convert ${frames[@]} -delay 50 -loop 20 ${temp}-m.gif
display -delay 1 ${temp}-m.gif
cat ${temp}-m.gif
/bin/rm -f noname.{red,grn,blu} ${temp}-*