doc/make-snapshot.sh

   1 #! /bin/sh
   2 #
   3 # make-snapshot.sh <application> <filename>
   4 #
   5 # Make a snapshot from an application's start window and save it to a file.
   6 # This needs X11 and ImageMagick's `import' tool.
   7 #
   8 # This script is very simple.  Some possible problems:
   9 #
  10 # o In case the program doesn't create a visible X11 window, you have to
  11 #   abort the script with ^C.
  12 #
  13 # o It fails for intelligent applications like `firefox' in case they are
  14 #   already run, since firefox replaces the process with a new window of the
  15 #   already running instance.
  16 #
  17 # o It loops forever for programs like `k3b' which spawns itself, thus
  18 #   having a different process ID for the visible window.
  19
  20
  21 # This script uses ideas from
  22 # http://blog.chewearn.com/2010/01/18/find-window-id-of-a-process-id-in-bash-script/.
  23
  24 if [ $# -ne 2 ]; then
  25   echo "Usage: $0 application imagename"
  26   exit 1
  27 fi
  28
  29
  30 find_WID()
  31 {
  32   # Get all windows with the name $APP (ignoring case).
  33   xwininfo -root -tree 2>/dev/null \
  34   | grep -i $1 \
  35   | while read DATA; do
  36       # Extract Window ID.
  37       WID=`echo $DATA | awk '{print $1}'`
  38
  39       # Check whether the window's PID is matching the application's PID.
  40       if [ `xprop -id $WID _NET_WM_PID | awk '{print $3}'` -eq $PID ]; then
  41         # Check whether window is displayed actually.
  42         if [ "`xwininfo -id $WID | grep 'IsViewable'`" != '' ]; then
  43           echo $WID
  44           return
  45         fi
  46       fi
  47     done
  48 }
  49
  50
  51 # Start program in background and get its process ID.
  52 $1 &
  53 PID=$!
  54
  55 sleep 1
  56
  57 # Get application name.
  58 APP=`ps --no-header -o comm -p $PID`
  59 if [ "$APP" == "" ]; then
  60   echo "Couldn't start application \`$1'"
  61   exit 1
  62 fi
  63
  64 # Loop until program has displayed a window
  65 # so that we can actually get the Windows ID.
  66 while [ "$WID" == "" ]; do
  67   WID=`find_WID $APP`
  68   sleep 1
  69 done
  70
  71 # Make snapshot.
  72 import -silent -window $WID $2
  73
  74 kill $PID
  75
  76 # eof