W3C home > Mailing lists > Public > public-html@w3.org > March 2011

Re: example spec text for longdesc

From: Laura Carlson <laura.lee.carlson@gmail.com>
Date: Fri, 25 Mar 2011 20:57:24 -0500
Message-ID: <AANLkTi=APerB9n2mWo0WvCrZMRv9X9YobMYgkC94aQDx@mail.gmail.com>
To: Jonas Sicking <jonas@sicking.cc>
Cc: Henri Sivonen <hsivonen@iki.fi>, HTMLWG WG <public-html@w3.org>
Hi Jonas,

Thank you very much for your email and comments. I really appreciate it.

>> What are appropriate way to solve the formal use cases?
>> http://www.d.umn.edu/~lcarlson/research/ld.html#uc
>
> I would love it if we could actually talk about it this way,

Me too.

> so I'll just take this invitation and run with it.

Thank you.

> First of all it has always surprised me that the list of use cases
> only list discusses adding accessibility information to images. Is
> there a reason things like tables, SVG (and portions thereof), figures
> and forms are left out?

Do you mean that tables, SVG (and portions thereof), figures and forms
are left out as they do not have mechanisms for providing a long
descriptions?

Would it be possible to make longdesc a global attribute? What would
be the pros and cons?

> Also, ease of use seems to be missing from that page. This isn't
> really a use case but rather a requirement.

Longdesc is a link so it is simple in that regard. Ease of use and
simplicity are pretty evident in the formal use case scenarios. For
instance:

http://www.d.umn.edu/~lcarlson/research/ld.html#us-01
http://www.d.umn.edu/~lcarlson/research/ld.html#us-02
http://www.d.umn.edu/~lcarlson/research/ld.html#us-07
http://www.d.umn.edu/~lcarlson/research/ld.html#us-08

> However since the page
> seems to be lacking a section for requirements maybe it would be ok to
> list under use cases.
>
> Would it be ok for me to go add these requirements to the wiki?

Requirements are linked:
http://www.w3.org/html/wg/wiki/ChangeProposals/InstateLongdesc#Requirements

But I can flesh that out and add ease of use, etc.

> Once you include these use cases and requirements it seems much less
> that longdesc is a proper solution.
>
> It's only available on <img>ages
> (this missing all other ways even for including images such as
> <canvas> and <object>).

Yes. Images are what we have been talking about.

> It isn't very user friendly. Lots of people
> seem to misunderstand it to include the actual describing text rather
> than a link to it.

That's where better conformance tool and authoring tool checking along
with more implementation would come in.

> Not only that, but since it is url based, rather
> than id based, it encourages people to put the description in an
> external resource, which more often than not is not what you want to
> do.

Being an external resource is very important in many situations. For
examples visit:

Describing a Logo
http://www.d.umn.edu/~lcarlson/research/ld.html#uc-01

Describing an Email Banner
http://www.d.umn.edu/~lcarlson/research/ld.html#uc-07

Describing Illustrations
http://www.d.umn.edu/~lcarlson/research/ld.html#uc-08

Facilitating etext Image Descriptions Describing etext Images
http://www.d.umn.edu/~lcarlson/research/ld.html#uc-09a

> It turns out that ARIA already have a attribute that almost fits the
> bill, and this is aria-describedby. As is pointed out on the wiki
> page, the problem is that the ARIA specification only allows exposing
> text content to the user, rather than arbitrary content, such as
> links.
>
> This problem can be fixed though by changing the ARIA specification.
> By changing ARIA to say that aria-describedby can point to arbitrary
> content, rather than just refer to the textual contents of it, we
> solve multiple problems in one go.
>
> This would first of all allow aria-describedby to solve all the use
> cases in the wiki, as well as the ones pointed out in this message. It
> also seems to fulfill the ease of use requirement better as people so
> far seems to put an id in aria-describedby rather than the actual
> text.

aria-describedat has been discussed. There are quite a few reasons
that it does not seem workable.
http://www.w3.org/html/wg/wiki/ChangeProposals/InstateLongdesc#aria-describedat

Sean Hayes just wrote up  "Configuring Internet Explorer to Handle
Longdesc" It adds a context menu entry to extract the longdesc
attribute value and have the page navigate to its content.
http://blogs.msdn.com/b/accessibility/archive/2011/03/25/configuring-internet-explorer-to-handle-longdesc.aspx

Jonas, is something like that doable natively in FireFox?

Thanks again.

Best Regards,
Laura
-- 
Laura L. Carlson
Received on Saturday, 26 March 2011 01:57:56 UTC

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