# Omnimap image mapper

Omnimap is a dynamically loaded MST (Message-based Service Thread) that allows the HTTP server to efficiently support clickable images and URL pointer files. The omnimap service processes the request from a fork inside the server rather than running an external script (the traditional way of handling image maps).

## Configuration

Like all MST's, the omnimap service must be declared inside the HTTP server's configuration file, assigned a thread pool, and bound to a virtual script (exec) directory.

## File formats (scriptname)

The exec rule used to configuration the omnimap service defines a virtual script directory. The first element following the directory, where in a conventional script the script name would go (e.g. /htbin/cgi-mailto), must specify a sub-function to indicate the format of the input file. The input file is given by the remaining path in the URL, what in CGI (Common Gateway Interface) scripts is known as the PATH_INFO.

### Htimage (/htimage)

The htimage format is that used by the htimage.c script program originally distributed with the CERN web server software. The map file describes rectangles, circles, and polygons and hot areas.

### NCSA mapimage

The NCSA imagemap format is used by the mapimage.c script program

### URL pointer (/url)

The URL pointer sub-function simply reads the first line of the input file and assumes that it is a URL to which the client must be re-directed.

## Examples

htimage format (nagel23a.htimage):

NCSA mapimage format (nagel23a.ncsa):

Pointer file indirection to URL in file omnimap.indirect.