#!/bin/bash

# Windowmovie: take a movie of a window for a specified amount of time and
# save it as an animated GIF.

if [ "$1" == "--help" ]; then
  cat <<EOF
Usage: windowmovie [--screen] [--help]
       --screen:    Film the whole screen
       If --screen is not specified, select a window by
       clicking with the cross cursor.
EOF
exit
fi

if [ "$1" == "--screen" ]; then
  WHOLESCREEN=yes
else
  WHOLESCREEN=no
fi

# Check for dependencies
if [ -z "`which zenity`" ]; then
  echo "Windowmovie requires the zenity program."
  exit
fi

if [ -z "`which xwd`" ]; then
  zenity --info --text "Windowmovie requires the xwd program."
  exit
fi

if [ -z "`which convert`" ]; then
  zenity --info --text "Windowmovie requires the convert program from ImageMagick."
  exit
fi

MYPID=$$
BEFORESTART=3
ODIR=/tmp/windowmovie.$MYPID

mkdir $ODIR

if [ $WHOLESCREEN == 'no' ]; then
  LOOPTIME=`zenity --entry --entry-text 10 --text "Choose a window when the \
cursor changes to a cross. For how long should the movie run?"`
else
  LOOPTIME=`zenity --entry --entry-text 10 --text "For how long should the movie run?"`
fi

if [ -z "$LOOPTIME" ]; then exit; fi

sleep $BEFORESTART

echo -e '\a'
if [ $WHOLESCREEN == 'no' ]; then
  WINDOWID=`xwininfo | grep "Window id" | cut -d" " -f4`
  while :; do xwd -id $WINDOWID -silent -out $ODIR/`date +%s%N`.xwd; done &
  SUBPID=$!
else
  while :; do xwd -root -silent -out $ODIR/`date +%s%N`.xwd; done &
  SUBPID=$!
fi

sleep $LOOPTIME; kill -9 $SUBPID  2>&1 >/dev/null
echo -e '\a'

# Convert the files to an animated GIF
ANIM=windowmovie.`date --iso-8601=seconds`.gif
convert -delay 40 $ODIR/*.xwd $ODIR/$ANIM
mv $ODIR/$ANIM $HOME/Desktop/$ANIM

rm -rf $ODIR