Overview

This script takes snapshots of MEDM screens by opening them up in a virtual X display and using a screen capture utility. It then makes PNG thumbnails and builds a web page of these so that they can be viewed from off site. A cronjob reruns the image capture and web posting several times per hour.

All of the scripts are living in /cvs/cds/project/statScreen/.

Taking screen shots in the background

statScreen/bin/captureScreen.sh takes a screen shot of an X application and saves the image to statScreen/images/. This script does not require a physical display. Instead it uses 'Xvfb' (Xwindows Virtual Frame Buffer) to make a virtual display called :5 (which will cause problems if we ever use 6 monitors on mafalda). MEDM is then told to open its display on :5. Then the ImageMagik utility 'import' is told to capture the :5 display and save it as a PNG.

For the MEDM screens, there is a wrapper script grabMEDMScreens.sh which is what the cronjob actually runs. It takes a list of .adl files as an argument and captures the images of those screens.

The crontab on mafalda is setup to run the file 'statScreen/bin/cronjob.sh' calls grabMEDMScreens.sh with statScreen/etc/medmScreens.txtas the argument. This job will generate images in statScreen/images/.

To change/add MEDM screens to be captured, modify statScreen/etc/medmScreens.txt.

Empty lines and lines starting with # are ignored.