X11record - an X11 capture program which creates an animated gif

#!/bin/sh

#  x11record - an X11 capture program which creates an animated gif
#
# USAGE:
#
#   % x11record foo.gif  # creates animation GIF
#
# REQUIREMENTS:
#
#   * ImageMagick - to create animation GIF movies
#   * xwd         - to capture window's image
#   * xwininfo    - to get window's id
#   * ungifsicle  - to create GIFs
#   * awk         - for arithmetic
#   * mktemp      - for secure temporary files
#
# CREDIT: heavily based on the GPL-licensed 'x11rec'.  I reimplemented this
#         in /bin/sh so it wouldn't have a ruby dependency.
#
#
# Copyright (C) 2005 Benjamin Rutt < brutt@bloomington.in.us>
#     All rights reserved.
#     This is free software with ABSOLUTELY NO WARRANTY.
#
# You can redistribute it and/or modify it under the terms of
# the GNU General Public License version 2.

if [ $# -ne 1 ]; then
   echo "usage: `basename $0` <filename.gif>"
   exit 1
fi

requireutil () {
   while [ -n "$1" ]; do
       type $1 >/dev/null 2>/dev/null
 if [ $? -ne 0 ]; then
     echo Missing utility "$1". Please install it. >/dev/stderr
     exit 1
 fi
 shift
   done
}

requireutil grep mktemp xwininfo date awk convert xwd gifsicle

GIFOUT=$1
set -e
TD=`mktemp -d /tmp/x11record.XXXXXX`
set +e
echo "** Select an X window to record with a mouse. **"
ID=`xwininfo | grep "^xwininfo.*Window id:" | awk '{print $4}'`
echo "Window ID is $ID"
TSTART=`date +%s`
echo "** Type Ctrl+C to finish the recording. **"
FRAMES=0
function x11recfinish {
   trap 2
   TSTOP=`date +%s`
   elapsed=`awk "BEGIN { print $TSTOP - $TSTART}"`
   echo
   echo "elapsed: $elapsed seconds"
   if [ $elapsed -eq 0 ]; then
       echo "ERROR: movie too short!"
       exit 1
   fi
   if [ $FRAMES -eq 0 ]; then
       echo "ERROR: no frames!"
       exit 1
   fi

   N=0
   for f in $TD/*.xwd; do
 convert $f $f.gif
 rm -f $f
 N=`expr $N + 1`
 awk "BEGIN { printf \"\rconverted ${N}/${FRAMES}\" }"
   done
    echo

   DELAY=`awk "BEGIN { printf \"%d\", ($elapsed / $FRAMES) * 100}"`
   gifsicle --colors 256 -O2 --delay $DELAY $TD/*.gif > $GIFOUT
   rm -fr $TD
   if [ $? -eq 0 ]; then
       echo $GIFOUT created
 exit 0
   else
       exit 1
   fi
}

trap "x11recfinish" 2
echo
while true; do
   xwd -silent -id $ID > $TD/$FRAMES
   mv $TD/$FRAMES `awk "BEGIN { printf \"$TD/%08d.xwd\", $FRAMES}"` >/dev/null 2>&1
   FRAMES=`expr $FRAMES + 1`
   awk "BEGIN { printf \"\r${FRAMES} frames captured\" }"
done