About Image Decoding with Pixmaps

This document describes extensions to the Plexus server to support arbitrary hypertext documents from a mouse click on a picture.

Functionality discussed here isn't of much use unless you have XMosaic version > 1.1

The Brief Idea

The basic idea is to have an X11 pixmap where each spot on the pixmap is a specified color. This color corresponds to some document within the scope of the current HTTP server.

There are several benefits:

The Longer Description

  1. The user clicks on a picture. The picture is written in HTML as

    <A HREF="something.html"><IMG SRC="a_map.gif" ismap></A>

  2. The server sees that this is a query. It can't tell the difference between an x,y click or a user query, so more definate criteria needs to be met.
  3. The base file is something.html. This server checks for the existence of something.html_ismap.xpm If that pixmap exists, then...
  4. The server parses the pixmap. Pixmaps have a field in their color specs which allow for a comment. This comment can be
  5. The extension of that file (the one retrieved from the comment) is based on the extension of the base file name. The pixmap does not specify .gif, .au, or .html, the server will add that extension. This is to allow the same pixmap to server several types of media. (When xmosaic supports it -- only HTML files can be recognized with xmosiac <= 1.2)

More info / Disclaimer

Please contact me (or leave an annotation) with requests/ suggestions/ flames/ comments/ etc.
johnsonb@stolaf.edu

1. X PixMap format. Arnould Le Hors, lehors@sophia.inria.fr