Re: Proper use of labelledby vs describedby and definitions

With regards to the use of ARIA in "static" documents, I'd like to comment that in publishing there are use cases for describedBy when an alt property is not sufficient to provide a description. For example the publisher may not wish to provide both a pie chart and a table for visual users, but the content for a non-visual user is best provided by a hidden HTML table that is referenced by describedBy. In the case of digital eBooks in EPUB 3, which is built on HTML5, sometimes this table is added by university Disabled Student Services (DSS)  or volunteers to projects like Bookshare.org<http://Bookshare.org>. The tables are kept hidden as not to "alter" the presentation that the publisher intended.

HTML's longdesc was meant for this purpose, but as other visual events like canvas came to HTML, a better mechanism was needed. ARIA 1.1 proposes describedAt as an alternative that combines the best of longdesc and describedBy, in order words the use of URLs and the applicability beyond image elements.

The ability to use an external resource pointed to by describedAt enables descriptive resources or alternate modalities to be more easily reused and improved for digital eBooks that are "static", have been already packaged in EPUB, but may not yet have adequate descriptions.

I'd recommend checking out http://diagramcenter.org where much reference information can be found as to use case for standards, alternatives for images and tools for description.

Gerardo

Gerardo Capiel
VP of Engineering
Benetech

On Apr 23, 2014, at 6:03 AM, "Shane McCarron" <shane@aptest.com<mailto:shane@aptest.com>> wrote:

Huh.  Okay.

Just for my edification, can someone explain how an AT would know and convey where the definition of a term was in the following scenarios?

<dl>
   <dt id='def-my-term'>My Term</dt>
   <dt id='def-my-other-term'>My Other Term</dt>
   <dd>A definition of both My Term and My Other Term, which are roughly synonyms.</dd>
</dl>

<p>Some prose in which I reference the formal term <a href='#def-my-term' title='My Term'>My Term</a> in the course of discussing whatever.</p>




On Tue, Apr 22, 2014 at 5:10 PM, Matthew King <mattking@us.ibm.com<mailto:mattking@us.ibm.com>> wrote:
Shane,

I agree with James.

I'll go a bit further and say that I don't think any ARIA is required inside the main content of a static document formatted using HTML. The HTML has everything needed.

Unless I am forgetting something, The only value-add use of aria-labelledby I can think of in the respec formatting that has been discussed thus far is to label each of the complementary appendix regions. I can not think of any circumstances in the specification document where I believe aria-describedby should be used.

Matt King
IBM Senior Technical Staff Member
I/T Chief Accessibility Strategist
IBM BT/CIO - Global Workforce and Web Process Enablement
Phone: (503) 578-2329<tel:%28503%29%20578-2329>, Tie line: 731-7398
mattking@us.ibm.com<mailto:mattking@us.ibm.com>



From:        James Nurthen <james.nurthen@oracle.com<mailto:james.nurthen@oracle.com>>
To:        public-pfwg@w3.org<mailto:public-pfwg@w3.org>,
Date:        04/21/2014 02:33 PM
Subject:        Re: Proper use of labelledby vs describedby and definitions
________________________________




On 4/19/2014 7:20 AM, Shane McCarron wrote:
Also, when referencing a defined term elsewhere, should we also use describedby and point back to the terms description?  E.g., <p>I have some content where I am talking about <span class="internalDFN" aria-describedby="someID">theterm</span> and relating it to other things.</p>
I don't see why you would do this. Why would you introduce a description of a term which is available only to AT users? If this is useful then it should be available to everybody. If you decide that this is useful then a link to the term would probably be the best way to accomplish it.


--
Regards, James

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