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Re: feedback requested on WAI CG Consensus Resolutions on Text alternatives in HTML 5 document

From: Henri Sivonen <hsivonen@iki.fi>
Date: Mon, 17 Aug 2009 11:06:09 +0300
Cc: HTMLWG WG <public-html@w3.org>, W3C WAI-XTECH <wai-xtech@w3.org>
Message-Id: <D3A5CB68-A5A7-47F3-B277-44C912D1521A@iki.fi>
To: Maciej Stachowiak <mjs@apple.com>
On Aug 17, 2009, at 10:48, Maciej Stachowiak wrote:

> On Aug 17, 2009, at 12:30 AM, Henri Sivonen wrote:
>
>> On Aug 17, 2009, at 10:11, Henri Sivonen wrote:
>>
>>> * "After the end of an authoring session, the authoring tool does  
>>> not attempt to repair alternative content for non-text content  
>>> using text content that is equally available to user agents (e.g.,  
>>> the filename is not used)." (Quoted from ATAG 2)
>>>
>>> * Autogenerated alt="image", alt="" and alt=" " violate the ATAG 2  
>>> language quoted in the previous point.
>>>
>>> * Autogenerated alt="photo" might be spun not to violate it but  
>>> practically isn't materially different from alt="image".
>>>
>>> * Autogenerated role=presentation doesn't violate the ATAG 2 point  
>>> literally but does in spirit.
>>
>>
>> * If @title is considered to function as a substitute for alt in  
>> the absence of alt, the same autogeneration considerations apply to  
>> @title as well.
>>
>
> If that's so, then HTML5 is in conflict with ATAG2, as applied to  
> authoring tools.
>
> My interpretation, on studying ATAG2 more closely: I do not believe  
> the use of title to describe an image whose contents are unknown  
> would meet the ATAG2 definition of "alternative content":
>
> <http://www.w3.org/TR/ATAG20/#def-Equivalent-Alternatives>
> "Content that is used in place of other content that a person may  
> not be able to access. Alternative content fulfills essentially the  
> same function or purpose as the original content..."
>
> In such a case, the title does not have the "same function or  
> purpose as the original content", rather it is a best-effort attempt  
> to provide *something* given the lack of a proper alternative.
>
> ATAG2 only allows alternative content to be autogenerated if the  
> author is given the opportunity to accept, modify or reject. But it  
> doesn't have such a requirement for textual descriptions that are  
> not alternatives.
>
> I am not sure if this reasoning is in the spirit of ATAG2. For that  
> matter, I am not sure if the HTML5 approach will lead to good  
> accessibility outcomes compared to the alternatives. But that is my  
> reading of the letter of the relevant specs.

It's quite possible that what I said about @title is a leap as far as  
actual ATAG 2 language goes.

However, I would guess that putting autogenerated text in @title in  
order to make it non-empty isn't an attractive way to comply with the  
letter of specs for tool vendors, and I think autogenerating non-empty  
@titles wouldn't comply with the spirit of the specs anyway.

-- 
Henri Sivonen
hsivonen@iki.fi
http://hsivonen.iki.fi/
Received on Monday, 17 August 2009 08:06:57 GMT

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