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Re: ISSUE 30 @longdesc use cases

From: Charles McCathieNevile <chaals@opera.com>
Date: Mon, 23 Aug 2010 15:50:04 +0200
To: "David Singer" <singer@apple.com>
Cc: "HTML Accessibility Task Force" <public-html-a11y@w3.org>, "HTML WG" <public-html@w3.org>, "W3C WAI-XTECH" <wai-xtech@w3.org>, "'Barry McMullin'" <barry.mcmullin@dcu.ie>
Message-ID: <op.vhv8pqsbwxe0ny@widsith.local>
On Mon, 23 Aug 2010 14:34:06 +0200, David Singer <singer@apple.com> wrote:

> OK, I hesitate to ask, point this out.  It is perhaps a minor point.
>
> There is an assumption/assertion here that a long description is hugely  
> relevant but only through accessibility provisions.

I don't think so. I certainly assume no such thing.

I assume that there are designers who will *not* put such a notice on  
their page (a conclusion based on more than a decade of asking for such  
things, and talking to designers and the people who employ or contract  
them about why it doesn't happen).

> But there may easily be puzzled users who do not have vision issues.

Indeed. It's a good use case for implementing it in the browser (as we  
did).

The biggest flaw in our implementation is that we don't automatically  
notify the user whether there is a long description - they have to check  
for each iamge. (The browser+AT implementations I know *do* announce when  
there is a description available). We have a similar issue with accesskey,  
which we do better than other browsers (by providing easy access to all  
the defined accesskeys) but the user has to ask through a direct action if  
there are any rather than being able to have an active non-interfering  
notification.

> There is nothing wrong with a page that says "A detailed description of
> this can be found _here_.",

(except that it breaks the usability guideline to use distinctive text for  
links, which would suggest the link be in the earlier part of the sentence)

> and indeed this will, in fact, benefit a number of users other than  
> those using screen readers (users new to the subject, in some cases, for  
> example).

Indeed. Users who have limited vision, but don't typically use a screen  
reader for an example group that significantly expands the target  
audience. Another group is "people who don't actually understand the very  
intuitive graphics designed by the clever graphic artist" which has been a  
problem I have often suffered...

> Not using the attribute does not preclude you from building  
> informatively constructed web sites, does it? I don't find "A detailed  
> description of this can be found _here_." 'traumatic' or 'confusing',  
> myself, in general.

One difference is that you don't have any explicit association between the  
image and its description, whereas an img element with a longdesc  
attribute pointing to an absolute URL actually gets benefit from  
cut-and-paste construction.

Also, while this is perfectly possible, as I note above it doesn't seem to  
have taken off, and a reason I have often heard cited in discussion with  
people who might be expected to do this but don't has been that they don't  
want to mess up their visual design. (Yes, this is anecdotal evidence).  
The attribute has the advantage of meeting the use cases (internal or  
external descriptions can be linked with explicit association) without  
placing any constraint on design.

cheers

Chaals

> On Aug 23, 2010, at 14:02 , Joshue O Connor wrote:
>
>> To explain - I will quote Barry directly from the CFIT website.
>>
>> "Double-negative" because longdesc is not being used here — but I would
>> have liked to use it, and its use would have been absolutely
>> appropriate! It's just that weak user-agent support meant that using it
>> would potentially have left the long description actually unavailable to
>> people who might benefit from it. So instead, I decided to compromise
>> (somewhat) the experience of people who already could perceive the
>> graphical image perfectly well, and exposed the long description for all
>> users (even though it is redundant for the majority). This decision
>> then, logically, had the further effect of requiring an explanation —
>> for those majority users — of what a long description is and why — which
>> explanation, in turn, is redundant for those users who would normally
>> actually benefit from a long description!
>>
>> I humbly suggest that such a convoluted (nay, "traumatic"!) design
>> decision — genuinely existing "in the wild" — should count as legitimate
>> evidence of the use-case-need for longdesc!?" [3]
>>
>
> David Singer
> Multimedia and Software Standards, Apple Inc.
>
>


-- 
Charles McCathieNevile  Opera Software, Standards Group
     je parle français -- hablo español -- jeg lærer norsk
http://my.opera.com/chaals       Try Opera: http://www.opera.com
Received on Monday, 23 August 2010 13:51:09 GMT

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