Re: WAI-CG Consensus Recommendations on Alternative Text in HTML 5

Hi all,

I've added my 2 cents in-line:

Henri Sivonen wrote:
> On Jun 11, 2009, at 04:30, Janina Sajka wrote:
> 
>> This document is also available at the following URI;
>> http://www.w3.org/2009/06/Text-Alternatives-in-HTML5
>>
>> We look forward to working with you to make HTML 5 the best
>> accessibility solution yet.
> 
> 
> Thank you for documenting the WAI CG consensus.
> 
> I have three questions related to software generating <img> elements:
> 
>  1) The user creates a new HTML document in an HTML5-compliant future 
> version of a Dreamweaver-like product and saves it with a name. The user 
> then drags an image file from the Finder onto the document window and 
> the image is inserted into the document. The user presses command-S and 
> then command-Q. What attributes should the generated <img> element have?

JR: The consensus document does not attempt to dictate syntax for this 
case, but the following options agree with the consensus and Public WD 
of ATAG 2.0 (http://www.w3.org/TR/2009/WD-ATAG20-20090521/):

a. The tool leaves @alt out entirely, so that the code produced is invalid.

b. The tool makes use of some kind of 'autogenerated' or 'missing' 
attributes as per this paragraph in the consensus:
"In order to address both the validity and human generation concerns, we 
do not oppose the creation of 'autogenerated' and 'missing' attributes 
where either one of these could be used to make an image that does not 
have any human-generated text alternatives valid. (Note: It is important 
that this marker is not included in the alternative text string itself.)"


>  2) The user takes a photo with his/her cameraphone and uploads it to a 
> service such as Brightkite. The user has the option to add an SMS-like 
> short caption that will be rendered in addition to the photo in visual 
> browsing settings but is not forced to add a caption. What attributes 
> should the generated <img> element have when the photo appears 
> immediately on the Web? (Brightkite now says alt="Photo-feed". 
> Reference: http://brightkite.com/objects/80d0f32c11e311deab31003048c10834)

JR: If the photo appears "immediately on the Web" (without any 
"authoring session") or if the author ignores prompts for the short 
caption during their authoring session, then the tool may add an @alt 
value as long as it is a value that the user agent wouldn't know. So 
because the fact that this is a "photo" is information the user agent 
can't easily detect, alt="Photo-feed" is ok (though of course very 
suboptimal from a user perspective) - see ATAG 2.0 B.2.4.3. AND it would 
also be useful if an 'autogenerated' attribute (as mentioned earlier) 
were also added.


>  3) Point #5 under "Use Case 2 (author using a photo sharing site)" 
> instructs photo sharing sites to generating alt="Photo 1 of 50 of album 
> Paris 2009". Why is this approach recommended instead of generating 
> aria-posinset="1" aria-setsize="50" and an alt attribute that doesn't 
> repeat the set position data, e.g. alt="Paris 2009"?

JR: To clarify, this isn't an "instruction". This is an example of the 
kind of information that "allowed" because it is more readily available 
to the authoring tool than to a user agent (hopefully with an 
accompanying 'autogenerated' attribute).

PLEASE NOTE: All of your questions have involved the unfortunate cases 
where the author is either not given a chance to add a human-authored 
alternative or chooses not to. The Task Force and ATAG 2.0 have provided 
some guidance on these cases in the interest of trying to achieve some 
degree of graceful degradation, but it is important to remember that a 
human authored alternative is almost always superior. For this reason, 
it is very important that all of these tools continue to work on adding 
well-integrated support for the collection of human authored 
alternatives (e.g., similar to how the red underlining of words is a 
subtle mechanism for collecting spelling information from authors)

-- 
Jan Richards, M.Sc.
User Interface Design Lead
Adaptive Technology Resource Centre (ATRC)
Faculty of Information
University of Toronto

   Email: jan.richards@utoronto.ca
   Web:   http://jan.atrc.utoronto.ca
   Phone: 416-946-7060
   Fax:   416-971-2896

Received on Thursday, 9 July 2009 13:30:23 UTC