Re: Keeping HTML Simple & Format negotiation between Browser & Server

hoesel@chem.rug.nl (frans van hoesel)
From: hoesel@chem.rug.nl (frans van hoesel)
Message-id: <9305291251.AA00471@Xtreme>
Subject: Re: Keeping HTML Simple & Format negotiation between Browser & Server
To: www-talk@nxoc01.cern.ch
Date: Sat, 29 May 1993 14:51:02 +0100 (MDT)
In-reply-to: <9305290121.AA14188@wintermute.ncsa.uiuc.edu> from "Marc Andreessen" at May 28, 93 08:21:18 pm
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Marc wrote:
> 
> Pei Y. Wei writes:
> > However, one could think of lots of other applications where it would 
> > be easier and more appropriate to use area-overlay-buttons. Just look at
> > the numerous HyperCard stackwares that use ``invisible fields'' to
> > implement highly neat effects. This approach, however hard-coded but
> > no more than ``HREF='' is hard-coded, has the benefits of no necessary
> > dependence on a server.
> 
> I agree.
> 

So do I (for what it's worth)

> > An example of invisible/see-thru buttons overlaying an image -- face.gif
> > is visible, and has two invisible area oriented anchors pointing to 
> > eyes.gif and mouth.gif respectively. Probably unnecessary, but WIDTH & 
> > HEIGHT could be specified to handle scaling. Also, perhaps <FIGA> should
> > simply be <A>. :
> > 
> > 	<FIGURE SRC="http://sesame-st.org/whatis/face.gif" TYPE="image/gif"
> > 		WIDTH=100 HEIGHT=100>
> > 	  <FIGA HREF="http://sesame-st.org/whatis/eyes.gif" TYPE="image/gif"
> > 		x0=20 y0=10 x1=80 y1=30>
> > 	  <FIGA HREF="http://sesame-st.org/whatis/mouth.gif" TYPE="image/gif"
> > 		x0=40 y0=70 x1=60 y1=80>
> > 	  <FIGCAP>Spy a face</FIGCAP>
> > 	</FIGURE>
> 
> Looks good to me.  Two comments: my gut feeling is that coordinates
> should be in pixel space, and that if the browser scales the image it
> should readjust any transmitted coordinates to match when the user
> actually selects something.  And, I think it should be possible
> to specify more than one rectangle per "FIGA" (e.g...
> 
>  	  <FIGA HREF="http://sesame-st.org/whatis/mouth.gif" TYPE="image/gif"
>  		COORDS="40-60,70-80;90-100,120-130">
> 
> ...or something similar).
> 

And if you could add a keyword like TRANSPARENT=0 to specifiy that the
color with index 0 should be transparent I would be even more happy.

This would allow very easy creation of a HREF that is *exactly* only to
mouth and not some collection of rectangles!!!!!

And it's easy for the server too: only one rectangle (the size of the image)
and it only needs a check for the color, if it is not the transparant color,
then follow the link.

It also allows for non-rectangular images inside a document (allthough the
bounding box would be rectangular.

Alternatively, one could send a simple b/w image to specify the
mouth *exactly* and don't use transparant at all

- frans