D13. Using a Customized Browser Plugin for Rapid Web Based Development

Lawrence E. Brown, Alexander Antunes, Annette Saunders (Raytheon for NASA/GSFC )

Reference URL: http://lheawww.gsfc.nasa.gov/docs/xray/astroe/astroegof.html

For the production of WASABI (a web based observation visualization tool) it turned out to be effective to build a customized version of the Tcl/Tk plugin. We needed

• A way to read FITS files.
• A graphical interface to display sky images and recieve user input.
• An easy to use source of sky images appropriate for planning high energy observations.
• A way to fetch the images from arbitrary URLs.

For speed of development, we wanted to reuse existing code and a language and development environment we were familiar with. We had all the pieces we needed ``lying around'':

• The fitsTcl Tcl extension to read fits files.
• The POW Tcl extension as a graphical image display interface tool.
• Skyview was ideal for generating the images and functions as a defacto ``front end'' to WASABI. Skyview, incidentally, does not use Tcl/Tk at all.
• The net driver support in cfitsio allows for URL fetching.

We built a customized version of the Tcl/Tk plugin which included POW, fitsTcl, and cfitsio and then coded WASABI as a ``LHEA tclet''. Then, thanks to Tcl/Tk's rapid development capabilities and simple geometry management we were able to produce WASABI with minimal development overhead. We present our results and discuss limitations and difficulties.