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[Bug 10455] Mint a describedby attribute for the img element

From: <bugzilla@jessica.w3.org>
Date: Tue, 31 Aug 2010 02:49:29 +0000
To: public-html-a11y@w3.org
Message-Id: <E1OqGuf-00044B-Sc@jessica.w3.org>
http://www.w3.org/Bugs/Public/show_bug.cgi?id=10455





--- Comment #45 from Leif Halvard Silli <xn--mlform-iua@xn--mlform-iua.no>  2010-08-31 02:49:28 ---
(In reply to comment #43)
> (In reply to comment #39)

> Another very common use-case is a thumb-nail gallery, where activating the link
> presents the sighted user with a larger version of the image. I would argue
> that the thumb-nail images deserve the long-description,
   [ snip ]
> (In reply to comment #41)
> > But, no. Reading what Laura said [1], one has to come to the conclusion that it
> > is about semantics - @longdesc is supposed to link to a description of some
> > particular quality.
> 
> while semantics can play a role here, it is a *mechanism* to link longer
> descriptions of images to those images that is being sought out. How do we
> associate a longer description to an image that does not break other
> functionality or 'aesthetic' considerations?

Core to what Laura said is tht the @longdesc URL points to a resource that is
especially crafted for non-sighted. That's a quality thing. I also perceive in
some arguments that there is a link between this quality and the technical
solution: Since it is only of interest to non-sighted, it is not important that
it is accessible to sighted. (And my tests with image maps did manage to create
a solution which was accessible to screenreader users and textbrowser users.)

I assume that the "goal" of the usecase you described above, is that the <img>
is wrapped inside an <a> element, but that it still works. That is possible to
do, cross browser with the help image map:

See: http://software.hixie.ch/utilities/js/live-dom-viewer/saved/605

Simplified code: 
  <a href=longdesc ><img src=* alt=* usemap="#map"/></a>
  <map id="map"><area shape="rect" href="full-size" coords="0,0,999,99"
/></map>

This seemed to work in the big four: Firefox, Opera, Webkit, IE. HTML5,
however, has ridiculous requirements: Since that IMG elemetn has a @usemap,
then it is forbidden. I don't know why. I tested LiveDomViewer example in
VoiceOver: In VoiceOver then I could only (?) activate the longdesc URL.
Whereas without VoiceOVer, I could open the thumbnail. 

Perhaps you will file a bug againt HTML5 to make it legal? ...

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Received on Tuesday, 31 August 2010 02:49:31 UTC

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