Automating screenshots

One of the boring tasks about documentation is taking screenshots, and update those as the software changes. So I looked for a way to remove this anti-DRY and found some interesting stuff to automate taking screenshots and do other things with X-Window and window managers:

* `xwininfo` and `xprop`: allows you to extract a lot of info of your running X apps, and convinces you to keep away from X-Window hacking
* `xrestop`: a top-like resource monitor for X-Window server resources being used by X clients
* `xlsclients`: lists X clients and shows more compact information than wxininfo/xprop
* `wmctrl`: a nice window manager control tool, that allows you to use “regexps” by default to match window titles
* `import`: a nice replacement for piped artifacts involving `xwd`, `xwdtopnm` and `pnmtopng` or `convert`. No more `xwd | xwdtopnm | pnmtopng > screenshot.png` or `xwd | convert xwd:- screenshot.png`

With those tools I made a small script that start an application, makes a screenshot and terminates it:

#!/bin/sh

do_screenshot () {
local TITLE=”$1″
local FILE=”$2″
local WIN=`wmctrl -l | grep “$TITLE” | cut -f1 -d’ ‘`

if [ "$WIN" -ne "" ] ; then

wmctrl -a $TITLE
rm $FILE
import -frame -border -window $WIN $FILE

if [ "$?" -ne "0" ] ; then
echo “import failed”
fi

fi
}

# TITLE is used as a “regexp” to identify application’s window
# FILE is used to store the screenshot
# SPAWN is used to run the application
# TERM is used to terminate the application
TITLE=”OpenOffice.org Writer”
FILE=”/tmp/foo.png”
SPAWN=”oowriter -norestore”
TERM=”killall soffice.bin”

$SPAWN
sleep 2
do_screenshot “$TITLE” $FILE
$TERM

It needs some tweaking and is a kind of “brute force” (e.g. killall ), but it’s easy and works…