Client-Side Image Maps

Dave Raggett (dsr@hplb.hpl.hp.com)
Thu, 9 Feb 95 07:26:43 EST

Why do we need yet another mechanism for client-side image maps?

First, the new public domain lossless image format being developed
as a replacement for GIF87 and GIF89 includes direct support for
image maps as part of the image data. This allows authors to directly
specify hotzones using standard graphics tools. It also allows for
dynamically generated image maps.

Second, HTML 3.0 and its predecessor HTML+ include a way to specify
client-side image maps as part of the textual description needed for
non-graphical browsers. An example looks like:

<FIG src="welcomemap">
<P>Welcome to Acme Software Components Corp.
<UL>
<LI><A HREF="about_us.html" SHAPE="circle 50,50,40">About our company</A>
<LI><A HREF="products.html" SHAPE="rect 0,0,100,50">Our products</A>
<LI><A HREF="technology.html" SHAPE="rect 0,51,100,100">
Technology for the next century</A>
</UL>
</FIG>

This is to be compared to James' suggestion:

<MAP NAME="welcomemap">
<AREA SHAPE=CIRCLE COORDS="50,50,40" HREF="about_us.html"
ALT="About our company">
<AREA SHAPE=RECT COORDS="0,0,100,50" HREF="products.html"
ALT="Our products">
<AREA SHAPE=RECT COORDS="0,51,100,100" HREF="technology.html"
ALT="Technology for the next century">
</MAP>

You will note that HTML 3.0 allows for rich markup within alt text which
is not possible with HTML 2.0 or James' suggested approach. The HTML 3.0
FIG element further provides for figure captions, and text flow around
figures.

What additional benefits are gained with the MAP/AREA elements?

-- Dave Raggett <dsr@w3.org> tel: +44 272 228046 fax: +44 272 228003
Hewlett Packard Laboratories, Filton Road, Bristol BS12 6QZ, United Kingdom