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Re: Give @alt is not given due consideration in ARIA

From: Leif Halvard Silli <xn--mlform-iua@xn--mlform-iua.no>
Date: Fri, 17 Sep 2010 19:36:59 +0200
To: Richard Schwerdtfeger <schwer@us.ibm.com>
Cc: janina@rednote.net, public-pfwg-comments@w3.org, public-pfwg-comments-request@w3.org
Message-ID: <20100917193659759799.c9550963@xn--mlform-iua.no>
Hi Richard,

I must say that your reaction comes as a surprise:

* WAI-ARIA editor James Craig suggested that I send formal suggestions 
for WAI-ARIA to this list - see:

* As for "more than past the last call date to ARIA spec", the the W3 
issued a Last Call working draft yesterday, see:

* One of the question asked in the TR document, is "Does the algorithm 
to calculate accessible name work for user agents and for authors?" 
And my message is a documented "It does not work" answer to that 

I am sorry to have linked to the PF document instead of the TR 
document. Please treat the comment as if it pointed to the TR document 
- I have studied both, and AFAIC the relevants points have not changed.

The letter also contains a link to letter sent to wai-xtech@. Thus if 
Janina finds my points interesting, then she has every opportunity to 
give an answer in _that_ forum. I certainly hope that she as well as 
the former and present ARIA editors are intersted in dicssuing the 
issues I take up.  I have never expected debate to take place on this 

If you feel that my letter is formulated in a debative style or lacks 
documentation etc, then please say so, so I have the chance to add what 
you think is lacking.

Leif Halvard Silli

Richard Schwerdtfeger, Fri, 17 Sep 2010 11:41:41 -0500:
> Hi Leif,
> We are more than past the last call date to ARIA spec. you are 
> referring to. This list is for public comments for TR working drafts 
> and not editorial drafts. This is also not a discussion forum.
> There must be a communication issue somewhere on this. Perhaps Janina 
> can help as to the appropriate vehicle to communicate your concerns.
> Rich
> Rich Schwerdtfeger
> CTO Accessibility Software Group
> Leif Halvard Silli ---09/15/2010 07:33:06 PM---These are some 
> comments to the status of @alt inside ARIA 1.0 as per 31 of Agust 
> 2010's working dra
> From: Leif Halvard Silli <xn--mlform-iua@xn--mlform-iua.no>
> To: public-pfwg-comments@w3.org
> Date: 09/15/2010 07:33 PM
> Subject: Give @alt is not given due consideration in ARIA
> Sent by: public-pfwg-comments-request@w3.org
> These are some comments to the status of @alt inside ARIA 1.0 as per 31 
> of Agust 2010's working draft, 
> http://www.w3.org/WAI/PF/aria/complete
> Please *do* read my message to wai-xtech as well:
> http://lists.w3.org/Archives/Public/wai-xtech/2010Sep/0018
> I will not repeat all that is said there, here.
> I will however rephrase the summary of that letter, as follows (mostly 
> identical). Please note that my main focus is on how @aria-label, 
> @aria-labelledby and @alt works on the <img> element. Howeer, as I 
> wrote al this, I also tested role="img" on other elements, so it is not 
> without relevance for other elements than <img>.
> 1) GENERAL. @alt is under-mentioned and under-specced in ARIA. The 
> underspecification of @alt has lead to differing  implementations. Bad 
> for authors and users! Examples if the lack of attention to @alt: 
> #namecalculation
> Section 5.2.7 on the accessible name calculation algorithm  mentions 
> many attributes as example of "author" values - amongst them it 
> mentions HTML @title, @aria-label and @aria-labelledby. But it does 
> *not* mention @alt, which is the most important author provided content 
> of HTML4 ... 
> #aria-label
> Likewise, when it comes to the definition of @aria-label, then @title 
> is mentioned as its HTML parallel. Does that mean that @aria-label is 
> not need in HTML, since it has @title? Isn't @alt a more natural 
> parallel? 
> #textalternativecomputation
> Going back to the section 5.2.7, then @title is only mentioned at step 
> 2D, after the text node content has been considered. How can 
> @aria-label, with it high priority, be considered similar to the low 
> priority @title attribute? Please rather compare aria-label with @alt.
> #textalternativecomputation
> @alt is mentioned under the last list item of step 2A, and the text 
> says that aria-labelledby if present should have highest priority, then 
> comes aria-label if present and finally @alt if present. In practise, 
> for <img>, then ARIA supporting ATs first considers the role of 
> element. 
> In most AT, the default role of <img> is affected not only by the 
> presence of @role but also of whether @alt is empty or none empty. 
> * Thus, in practise, many AT consider if @alt is empty or non-empty 
> first, 
> * if non-empty then they prioritize aria-label - if present, else they 
> prioritize @alt's content. 
> * If @alt was emtpy, then they may not consider whether @aria-label 
> nor @aria-labelledby (AT differ on this)
> * but if @role="img" is present and alt is empty, *then* and only do 
> they look at @aria-labelledby
> Thus, it is all very convoluted.
> 2) What is supposed to happen if aria-labelledby points to an element 
> whose only content is located inside @alt, @title or @aria-label? 
>  AT differ in what they do: OSX10.5's VoiceOver and Jaws11+Firefox 
> consider @alt as the content, Jaws12+Firefox consider aria-label as the 
> content, NVDA consider both. I don't see where in the spec this 
> explained. (I think most authors will expect that aria-label points to 
> an element whose text node contetn will be used.) It is clear that 
> author provided values, such as aria-labelledby, has priority over the 
> element's own content text node. The question is what if 
> @aria-labelledby points to an element whose content author content 
> only, or a mix of author content and text node content?
> 3) ATs generally give @alt higher priority than ARIA says, and most of 
> them ignore @labelledby if @alt is non-empty.
> 4) For <img>, then ATs in practise links a double meaning to the empty 
> @alt: aria-labelledby generally only work as expected when the @alt is 
> the empty string. At the same time HTML5 says that empty @alt means 
> role="presentation".
> 5) A consequence of the fact that aria-labelledby is ignored when @alt 
> is non-empty (see 3) and 4) above)  is that it is impossible to get an 
> aria-labbelledby which points to <img> itself (<img id=A alt=FOO 
> aria-labelledby="A B">) to work, despite that ARIA says it should work. 
> (This might work better for <div role="img"> tha for <img role="img"> - 
> please check.)
> 6) The algorithm doesn't say what role it plays that the @alt is or 
> isn't the empty string. Which is just an example of how ARIA doesn't 
> incorporate the semantics @alt. But while ARIA doesn't take it in, it 
> is clear that AT in various degrees take it in. E.g consider the 
> convoluted way AT prioritize between @alt, @aria-label and 
> @aria-labelledby. (I don't claim that AT do it correct and tha ARIA do 
> it wrong - proably both AT and ARIA need fixing ...)
> A really important point to me is that AT should see the @alt as the 
> content of <img>. Perhaps ARIA should consider @alt more like text node 
> content than author content? Or, when I think about it: perhaps, that 
> is what you do - and perhaps that's the problem! Because, for other 
> elements, it doesn't matter for the element's semantics whether it is 
> empty or non-empty. Whereas for <img>, the <img alt=""> and <img 
> alt="non-empty"> are considered different beasts. 
> Sorry, a convoluted response to a convoluted problem.
> -- 
> leif halvard silli
Received on Friday, 17 September 2010 17:37:38 UTC

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