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Re: Drop longdesc, get aria-describedat?

From: Leif Halvard Silli <xn--mlform-iua@xn--mlform-iua.no>
Date: Wed, 14 Mar 2012 00:44:05 +0100
To: Janina Sajka <janina@rednote.net>
Cc: W3C WAI-XTECH <wai-xtech@w3.org>, HTML Accessibility Task Force <public-html-a11y@w3.org>
Message-ID: <20120314004405016574.78ae0ca1@xn--mlform-iua.no>
Where do we file bugs against ARIA? Is this the place:

https://www.w3.org/Bugs/Public/enter_bug.cgi?product=ARIA

?

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)
> 
> 
Received on Tuesday, 13 March 2012 23:44:37 UTC

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