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RE: Why an standalone image shall conform to WCAG 2.0? (was Re: BIG ISSUE -- re Delivery Units)

From: Gregg Vanderheiden <gv@trace.wisc.edu>
Date: Mon, 13 Feb 2006 10:08:27 -0600
To: "'Carlos A Velasco'" <Carlos.Velasco@fit.fraunhofer.de>
Cc: <w3c-wai-gl@w3.org>
Message-ID: <000001c630b7$bc484880$ee8cfea9@NC6000BAK>

Hi Carlos


The problem with the approach you suggest below is that you would have to
specify each delivery unit that conformed.   If you had a directory with
pages and all their resources, you can't specify that all the content in
that directory is accessible.  You would have to list the individual
delivery units that were accessible and keep updating the list every time
you changed or added a page.  Not very realistic for a large web site. (or
even a small one?)

 
With regard to your second question:
> For example, what if I claim the German version of my site (available via
language negotiation) is accessible, but the english (default) is not?

The working group decided that you can use content negotiation to get an
alternate inaccessible version but the default had to be accessible since
many user agents and users don't know how to do content negotiation.   So
the answer to your question is no. 

thanks


Gregg

 -- ------------------------------ 
Gregg C Vanderheiden Ph.D. 
Professor - Ind. Engr. & BioMed Engr.
Director - Trace R & D Center 
University of Wisconsin-Madison 
The Player for my DSS sound file is at http://tinyurl.com/dho6b 

-----Original Message-----
From: w3c-wai-gl-request@w3.org [mailto:w3c-wai-gl-request@w3.org] On Behalf
Of Carlos A Velasco
Sent: Monday, February 13, 2006 2:19 AM
To: Gregg Vanderheiden
Cc: w3c-wai-gl@w3.org
Subject: Why an standalone image shall conform to WCAG 2.0? (was Re: BIG
ISSUE -- re Delivery Units)


Hi Gregg,

You keep ignoring the critical question I raised in my first email to this
thread. Here is my last try. In [1] it is said:

<quote>
Conformance Notes

A delivery unit conforms to WCAG 2.0 at a given conformance level only if
all content provided by that delivery unit conforms at that level.
</quote>

That is senseless. Many DUs contain media elements that are made accessible
through the whole set of elements in the main DU, or via linked information
(e.g., longdesc). Cumbersome example: I can have in two different iframes
(or frames) a non-accessible PDF document and an accessible HTML version of
the same document. I think the page is accessible, isn't it (ignore frame
accessibility for the sake of the argument)? Thus the issues does not lie on
DUs, but on this paragraph.

Into other issues, the document follows ...

<quote>
Note: If multiple representations can be retrieved from a URI through
content negotiation, then the conformance claim would be for the delivery
unit that is returned when no negotiation is conducted (unless the server
returns an error for that condition, in which case one of the negotiated
forms must comply).
</quote>

I believe this is an over-simplification of [2]. This paragraph also
eliminates conformance claims linked to content-negotiation. For example,
what if I claim the German version of my site (available via language
negotiation) is accessible, but the english (default) is not?

regards,
carlos

[1] http://www.w3.org/TR/WCAG20/complete.html#N102E1
[2] http://www.w3.org/Protocols/rfc2616/rfc2616-sec12.html#sec12

Gregg Vanderheiden wrote:
>>> So we need to find a way to fix them or delete 8 or so of our core 
>>> success criterion.
> 
>> Which ones?
> 
> All of the ones that have delivery unit in them.
> 


--
Dr Carlos A Velasco - http://access.fit.fraunhofer.de/ Fraunhofer-Institut
für Angewandte Informationstechnik FIT
   [Fraunhofer Institute for Applied Information Technology (FIT)]
   Barrierefreie Informations- und Kommunikationstechnologie für Alle
   Schloss Birlinghoven, D53757 Sankt Augustin (Germany)
   Tel: +49-2241-142609 Fax: +49-2241-1442609
Received on Monday, 13 February 2006 16:08:37 GMT

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