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Re: Drop longdesc, get aria-describedat?

From: Janina Sajka <janina@rednote.net>
Date: Tue, 13 Mar 2012 19:54:55 -0400
To: Leif Halvard Silli <xn--mlform-iua@xn--mlform-iua.no>
Cc: W3C WAI-XTECH <wai-xtech@w3.org>, HTML Accessibility Task Force <public-html-a11y@w3.org>
Message-ID: <20120313235455.GE4810@sonata.rednote.net>
Leif Halvard Silli writes:
> Where do we file bugs against ARIA? Is this the place:
> 
> https://www.w3.org/Bugs/Public/enter_bug.cgi?product=ARIA
> 
Please look at:

Instructions - PFWG Public Comments
http://www.w3.org/WAI/PF/comments/instructions

Janina


> ?
> 
> Leif H Silli
> 
> Janina Sajka, Tue, 13 Mar 2012 19:35:51 -0400:
> > Well, there's certainly no reason you need to accept my word on any of
> > this. File a bug if you think it's a bug. That's the responsible thing
> > to do, no?
> > 
> > Janina
> > 
> > Leif Halvard Silli writes:
> >> To look blindly at 'calculation' is also to miss a point: You have 
> >> defined what an 'img' role is. You could have said that 'img' element 
> >> might also have 'description links', but that you have not defined what 
> >> a 'description links' precisely is and precisely how it is handled, in 
> >> the current version of ARIA.
> >> 
> >> Leif Halvard Silli
> >> 
> >> Janina Sajka, Tue, 13 Mar 2012 18:47:12 -0400:
> >>> You're missing my point.
> >>> 
> >>> There's no calculation relating to longdesc because there's no need for
> >>> it. As I keep reminding everyone, ARIA-DescribedAT does not exist.
> >>> There's no need to define rules for what to use, because there's no
> >>> competing ARIA markup that serves the use case of HTML's longdesc.
> >>> 
> >>> In the future, when we have an ARIA-DescribedAT, we will undoubtedly
> >>> need to say something here. But, that day has not dawned.
> >>> 
> >>> Meanwhile, ARIA-LabeledBy, -DescribedBy, etc., etc., all figure in alt
> >>> text. For this there is indeed the need to consider precedence, which
> >>> our doc attempts to do at great detail--because this calculation is
> >>> important.
> >>> 
> >>> PS: This should actually serve as further evidence that ARIA-DescribedBy
> >>> isn't about long text alternatives but rather about short text
> >>> alternatives, about that attribute known as "alt text" in html.
> >>> 
> >>> Janina
> >>> 
> >>> Leif Halvard Silli writes:
> >>>> Janina Sajka, Tue, 13 Mar 2012 15:15:24 -0400:
> >>>> 
> >>>>>> ARIA defines where @title and @alt fits in in ARIA: In the accessible 
> >>>>>> name. But ARIA does not explain where the longdesc link - or if you 
> >>>>>> wish: an image with a longdesc - fits in.
> >>>>>> 
> >>>>> So?
> >>>>    [ snip ]
> >>>>>> However, while, ARIA expects AT to say 'image' if the element has 
> >>>>>> role=img, and expects the accessible name to be presented as the 
> >>>>>> content of the image, it  does not explain when and where the mere 
> >>>>>> presence of a longdesc should be conveyed to the user. ARIA is silent. 
> >>>>>> And makes no implicit expectations.
> >>>>>> 
> >>>>> No reason we should. You still haven't made the case that we are
> >>>>> obligated to do this, or that we have a reason to do it.
> >>>> 
> >>>> That compelling reason, is found in the description of the img role: [1]
> >>>> 
> >>>>    "An img can contain captions and descriptive text, as well as 
> >>>> multiple image files that when viewed together give the impression of a 
> >>>> single image." 
> >>>> 
> >>>> Further more the characteristics section links to IMG in HTML4 and 
> >>>> IMGGROUP in DTB. The later consist of one or more IMG, and each IMG may 
> >>>> contain longdesc.]
> >>>> 
> >>>> Hence, many in the readership of ARIA 1.0, will assume that 'img' here 
> >>>> is linked to HTML, whose image element is named <img>. And thus, that 
> >>>> 'img' is formulated after the model of <img>. And so I ask: Where is 
> >>>> HTML4's @longdesc in that description?  And where is it said that one 
> >>>> might actually also find a description link inside an 'img'? The 'img' 
> >>>> model of ARIA simply looks incomplete. [I had similar input during your 
> >>>> last call too, but ...]
> >>>> 
> >>>>> From the accessible name calculation section and from other places in 
> >>>> ARIA 1.0, it is further clear that an role 'img' element, from an AT 
> >>>> perspective, only contains 'author' provided content. Thus: No 
> >>>> 'contents' content. [For other readers: 'Author' content refers to 
> >>>> contend specified via attributes: alt, title, aria-label, 
> >>>> aria-labbelledby, aria-describedby. The clue is that AT only presents 
> >>>> to the user such content that is explicitly referred to - or contained 
> >>>> - in the designated attributes. ]
> >>>> 
> >>>> And so I ask: Is @longdesc 'author' provided content or 'contents'? It 
> >>>> is clearly author provided - it contains a 'human inserted' URL. And 
> >>>> so, from that perspective, it fits right into ARIA's model of 'img'. 
> >>>> The only - somewhat dull - issue, is that @longdesc does not contain an 
> >>>> author provided 'link text'. Only an author provided URL. It is an 
> >>>> on/off thing: It is the author who adds it, or not. And then there is a 
> >>>> standard presentation of that link.
> >>>> 
> >>>> The description of the 'img' role, also says: 
> >>>> 
> >>>>    "In order for elements with a role of img be perceivable, authors 
> >>>> SHOULD provide alternative text or a label determined by the accessible 
> >>>> name calculation." 
> >>>> 
> >>>> Which makes me ask: What about a link to a longer description for the 
> >>>> image? SHOULD or MAY authors provide that? Do some images need - or not 
> >>>> - a long, independent description in order to be perceivable?
> >>>> 
> >>>> Apparently, the ARIA task force *did* think that one description links 
> >>>> are sometimes needed, because one or two ARIA specs/guides tell/told 
> >>>> how one can use @aria-describedBY plus an anchor element to do that ... 
> >>>> However the very description of the 'img' role, does not mention it ...
> >>>> 
> >>>>>> An image with longdesc indicates 'complex data image'. Hence, it seems 
> >>>>>> logical with an early announcement about the presence the longdesc.
> >>>>>> 
> >>>>> Complex data? Maybe. Maybe not. Maybe it's a painting by Raphael. I
> >>>>> would not characterize a long description of a painting as data
> >>>>> structure.
> >>>> 
> >>>> Right. I should have skipped 'data' and only said 'complex' - or said 
> >>>> 'complex or data filled'.
> >>>> 
> >>>> My main point here, was *early announcement*, so the user can choose to 
> >>>> go for the long description instead of having to listen to the short - 
> >>>> but possibly still long - alternative text. Longdesc is binary thing: 
> >>>> Either it exist, or it doesn't. And so, its presence says something 
> >>>> about the 'nature' of the element. That is why I likened to a sort of 
> >>>> role. And something to be announced early.
> >>>> 
> >>>> Also, I think it is correct to say that *the author* [remember: 
> >>>> 'author' provided content] consider the 'img' to be complex. The author 
> >>>> decides what the 'img' needs. May be the 'img' doesn't contain so much 
> >>>> 'data'. But the author still considers that an independent description 
> >>>> is warranted, in order to go deep enough into its complexity.
> >>>> 
> >>>> [1] http://www.w3.org/TR/wai-aria/complete#img
> >>>> -- 
> >>>> leif halvard silli
> >>> 
> >>> -- 
> >>> 
> >>> 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)
> > 
> > 

-- 

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 Tuesday, 13 March 2012 23:55:21 UTC

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