Re: Cougar DTD img USEMAP & ISMAP

Harold A. Driscoll (harold@driscoll.chi.il.us)
Fri, 12 Jul 1996 17:26:53 +0100


Message-Id: <2.2.32.19960712162653.00ac4624@pop.interaccess.com>
Date: Fri, 12 Jul 1996 17:26:53 +0100
To: Aymeric.PoulainMaubant@enst-bretagne.fr
From: "Harold A. Driscoll" <harold@driscoll.chi.il.us>
Subject: Re: Cougar DTD img USEMAP & ISMAP
Cc: www-html@w3.org

At 17:52 12/7/96 +0200, Aymeric Poulain Maubant wrote:
>I'm not sure of this, but does the following extract of the cougarDTD
>mean that an IMG can be USEMAP and ISMAP *at the same time* ?
>
><!ELEMENT IMG    - O EMPTY --  Embedded image -->
><!ATTLIST IMG
>        %style;     -- id, class, style --
>        src     %URL     #REQUIRED  -- URL of image to embed --
>        alt     CDATA    #IMPLIED   -- for display in place of image --
>        align   %IAlign  #IMPLIED   -- vertical or horizontal alignment --
>        height  %Pixels  #IMPLIED   -- suggested height in pixels --
>        width   %Pixels  #IMPLIED   -- suggested width in pixels --
>        border  %Pixels  #IMPLIED   -- suggested link border width --
>        hspace  %Pixels  #IMPLIED   -- suggested horizontal gutter --
>        vspace  %Pixels  #IMPLIED   -- suggested vertical gutter --
>        usemap  %URL     #IMPLIED   -- use client-side image map --
>        ismap   (ismap)  #IMPLIED   -- use server image map --
>        title   CDATA    #IMPLIED   -- advisory title string --
>        >

Check out <draft-ietf-html-clientsideimagemap-01.txt> which describes the
client-side image map proposal. [1]

I would expect that in most "real world" cases ISMAP would be used with
USEMAP. This allows those browsers which support client side image maps to
do so, while relying on the Web server to handle those cases where the
browser can't.

/Harold
==================
[1] "A Proposed Extension to HTML : Client-Side Image Maps"  (James L.
Seidman, <draft-ietf-html-clientsideimagemap-01.txt>, December 1, 1995,
http://ds.internic.net/internet-drafts/draft-seidman-clientsideimagemap-02.t
xt ) expects:

2.1 Syntax
   
   Adding a USEMAP attribute to an IMG element indicates that it is a
   client-side image map.  The USEMAP attribute can be used with the
   ISMAP attribute to indicate that the image can be processed as
   either a client-side or server-side image map.  The argument to
   USEMAP specifies which map to use with the image, by specifying the
   URI for the file containing the map, followed by a '#', followed by
   the name of the map.  If the argument to USEMAP starts with a '#',
   the map is assumed to be in the same document as the IMG tag.  The
   presence of a USEMAP attribute overrides the effect of an enclosing
   anchor (A) element.

   [...]

as well as:
   
2.2  Required Changes to HTML/2.0 DTD

   The required changes to the HTML/2.0 DTD to support this syntax
   would be as follows:

      Change the IMG element definition to be:
        <!ELEMENT IMG    - O EMPTY>
        <!ATTLIST IMG
                SRC CDATA #REQUIRED
                ALT CDATA #IMPLIED
                ALIGN (top|middle|bottom) #IMPLIED
                ISMAP (ISMAP) #IMPLIED
                USEMAP %URI; #IMPLIED
                %SDAPREF; "<Fig><?SDATrans Img: #AttList>#AttVal(Alt)</Fig>"
        >

   [...]
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Harold A. Driscoll                       mailto:harold@driscoll.chi.il.us
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