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[Bug 9214] Allow role="presentation" img as conformance Criteria

From: <bugzilla@jessica.w3.org>
Date: Tue, 07 Sep 2010 16:03:58 +0000
To: public-html-a11y@w3.org
Message-Id: <E1Ot0eM-0001sl-1m@jessica.w3.org>
http://www.w3.org/Bugs/Public/show_bug.cgi?id=9214





--- Comment #25 from Leif Halvard Silli <xn--mlform-iua@xn--mlform-iua.no>  2010-09-07 16:03:56 ---
Thanks. Formally, you have now responded to Cooment #16. The exact point in you
change proposal which speaks to this bug, is found under the heading called
“role="presentation" Attribute”.


http://www.w3.org/html/wg/wiki/ChangeProposals/ImgElement20090126#role.3D.22presentation.22_Attribute

That section does indeed confirm that you want <img role="presentation" 
src="foo" /> to be valid, despite that there is no @alt attribute inside. 
Thus, this this bug relates to the question about how ARIA is permitted to be
used inside HTML5, this bug seems also very related to bug 10066 - "replace
section 3.2.6 with the alternative spec text provided (ARIA)".  I think that
the correct context to solve this problem, should be the context of 10066.

It surprises me that you want the lack of @alt to be valid, since the entire
working group earlier have heard you explain how an <img> in lack of @alt 
should not in any way be considered valid.

Below follows my evaluation of the 3 arguments you use in the Change Proposal:


1st argument:  ]] It is specified and implemented to do what alt="" is
specified to do. [[

    Evaluation:  This is argument doe not hold true, because:

     (1) role="presentation" has no effect in user agents which do not support
ARIA. 
     (2) Whenever the @alt attribute is non-empty, then role="presentation"
will - in ARIA supporting user agents, overrule the @alt: to ARIA supporting
AT, then for example this element: <img alt="foo" role="presentation">, will
not be presented to the user. Whereas the user not accessing the page via AT
will, in case the @src attribute is incorrect or the user agent does not have
image display, willl get to see the @alt text as fallback. 

3rd argument: ]] As per the rules specified in current spec pertaining to its
use [24], the use of role="presentation" is not dis-allowed on the img element
it is in fact stated that it is the only role that can be applied to an img
that has an alt="", so you can do this: <img role="presentation" alt=""> and no
where in the aria section [24] does it state you can't do this: <img
role="presentation"> but it will result in a conformance error, which appears
both incongruous and illogical. [[ 

     Evaluation: I feel that 3rd argument, except for emphasizing logic, is
just a variant of the 1st argument. However, since 1st argumetn does not hold
true, I won't comment it anymore.


2nd argument: It is non specific, it works on all elements.

     Evaluation: this, in my view, is the best argument  that you offer. In
fact, I think it is a quite good argument in favor of allowing
@role="presentation" also on images that *does* have @alt text. For instance,
it is thinkable that Ian could turn the ASCII art of his e-mail signature into
an image, and insert it into HTML documents with the IMG element, using the
ascii art as fallback content inside the @alt attribute, like this:

<img src="cat-image-signature" role="presentation"  alt="
  )\._.,--....,'``.    fL
 /,   _.. \   _\  ;`._ ,.
`._.-(,_..'--(,_..'`-.;.'
" >

However, the current editors draft *does* allow role="presentation" even when
the @alt contains text. Hence the 2nd argument really is largly already met. 


Conclusions:

(1) If an author *only* wants to focus on users which use ARIA supporting AT to
read web pages, then I agree that adding role="presentation" to an image which
is lacking @alt text, could be considered enough - to inform the author that
the page lacks @alt will not offer anything.  Just as the spec currently
operates with the loophole that authors may drop the @alt in private
communication, I think it is logical that one could also drop the @alt in favor
of role="presentation" whenever one knows that the consumer(s) use ARIA
supporting AT. However, you don't argue in favor of any such ARIA related
"loophole", but argue generallly. Your opposition agains the private
communication loophole, which I too oppose, does not make it logical that you
want anther loophole.

(2) Thus, having considered your arguments,  the only thing left is that if the
author removes the @alt attribute, then the addition of @role="presentation"
does not affect the validity of the <img>. But considering your previous
strongly voiced argumentation in favor of saying that no <img> element should
be considered valid, unless it contains the @alt attribute, I think you should
reevaluate your position regarding @role="presentation" - and thus also remove
that point from your change proposal.

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Received on Tuesday, 7 September 2010 16:04:00 UTC

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