Re: proposed new tag: IMG

Thomas A. Fine (fine@cis.ohio-state.edu)
Mon, 1 Mar 93 15:21:36 -0500


Here's my opinion.

The best way to do images in WWW is by using MIME. I'm sure postscript
is already a supported subtype in MIME, and it deals very nicely with
mixing text and graphics.

But it isn't clickable, you say? Yes your right. I suspect there is
already an answer to this in display postscript. Even if there isn't
the addition to standard postscript is trivial. Define an anchor
command which specifies the URL and uses the current path as a closed
region for the button. Since postscript deals so well with paths, this
makes arbitrary button shapes trivial.

Let's call this specially modified postscript HTPS. Until HTPS becomes
some sort of standard, every copy of HTPS should include a piece of code
that asks the interpreter if it knows about the anchor command, and if
it doesn't it will substitute in a null command.

As far as implementation, this is easy, though not necessarily trivial.
Ghostscript already provides the ability to bind arbitrary functions to
mouse events. It shouldn't be too horrible to set up anchor to keep
a table of button paths, and have mouse clicks call a function that looks
up what button they are in.

Let me point out that it wouldn't be hard to make such a system deal
with html too. Many people already have code that converts html to
postscript.

tom