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Re: Response to: ChangeProposals/DeprecateLongdesc

From: Janina Sajka <janina@rednote.net>
Date: Wed, 24 Aug 2011 11:37:29 -0400
To: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
Cc: public-html-a11y@w3.org
Message-ID: <20110824153729.GG8391@sonata.rednote.net>
Hi, Silvia:

I believe you're referring to:
WAI CG Consensus Recommendations on Text alternatives in HTML 5
http://www.w3.org/2009/06/Text-Alternatives-in-HTML5.html

My best recollection is that we wanted to be forward looking. Note that
we were particularly concerned to support rich content structures in
alternative text mechanisms. Note, however, that the conditions named
for describedby are not met particularly at this point. We lost the rich
text unless the describedby content is on screen for all comers.


Note also that the expectation was a two-step use of describedby, where
the user would need to activate a URI to access the bulk of alternative
longer description, quoting:

"If aria-describedby can point off page (by pointing to a link on the
page) ..."

This approach was eventually rejected after wider discussion. It has not
been raised again, including by the current proposal.

Janina


Silvia Pfeiffer writes:
> Janina,
> 
> I have a quick question: in the document that you pointed out,
> @aria-describedby is listed under long descriptions. The explanation
> for long descriptions in turn states that they are explicitly meant
> for user-initiated reading only. So, now I wonder why
> @aria-describedby has been implemented as a mechanism that is not
> user-initiated? Would that maybe be a browser bug?
> 
> Thanks for helping me understand.
> 
> Cheers,
> Silvia.
> 
> On Wed, Aug 24, 2011 at 8:31 AM, Janina Sajka <janina@rednote.net> wrote:
> > Silvia Pfeiffer writes:
> >> The problem of aria-describedby automatically starting to read out the
> >> description is not as a big a problem as you make it out to be. Every
> >> screen reader has a key that stops the screen reader from continuing
> >> to read what it is currently reading ...
> >
> >
> > And then what? Are we to  abandon reading anything else on the page? If
> > we resume, where do we resume? Right in the middle of that
> > long-description that wasn't so interesting and caused us to stop speech
> > in the first instance?
> >
> > No, Silvia, it won't work that way. This is a problem. It's a problem
> > that has long been resolved, but one that HTML5 seems to want to force
> > on us again.
> >
> > The historic resolution is that we have two mechanisms:
> >
> > 1.)     A short stand-in for the graphic/figure which serves to identify
> > it. This is called the alt attribute and is automatically read.
> >
> > 2.)     The long text alternative description which provides more
> > detailed information about the image. In HTML4, and in our TF consensud
> > proposal, it's called longdesc, and it's read only when the user
> > requests it be read.
> >
> >
> > Asking for an element/ or attribute to behave both ways, sometimes auto
> > read, sometimes read only upon request, is nonsense because there's
> > simply no reliable way to support both behaviors in the same mechanism.
> > The one subverts the functionality of the other. You can't have it both
> > ways in the same mechanism.
> >
> > Please note we defined this, howbeit tersly, two years ago in:
> > WAI CG Consensus Recommendations on Text alternatives in HTML 5
> > http://www.w3.org/2009/06/Text-Alternatives-in-HTML5.html
> >
> >
> > PS: What I think you're on the verge of re-inventing is something we
> > called "Escapable Structures" in DAISY. When one begins to read a long
> > "subroutine" of the primary text, perhaps a complex table, one might
> > decide to stop reading that structure and resume reading the primary
> > content, ergo "Escapable Structures."
> >
> > Janina
> >
> > --
> >
> > Janina Sajka,   Phone:  +1.443.300.2200
> >                sip:janina@asterisk.rednote.net
> >
> > Chair, Open Accessibility       janina@a11y.org
> > Linux Foundation                http://a11y.org
> >
> > Chair, Protocols & Formats
> > Web Accessibility Initiative    http://www.w3.org/wai/pf
> > World Wide Web Consortium (W3C)
> >
> >
> >

-- 

Janina Sajka,	Phone:	+1.443.300.2200
		sip:janina@asterisk.rednote.net

Chair, Open Accessibility	janina@a11y.org	
Linux Foundation		http://a11y.org

Chair, Protocols & Formats
Web Accessibility Initiative	http://www.w3.org/wai/pf
World Wide Web Consortium (W3C)
Received on Wednesday, 24 August 2011 15:37:53 GMT

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