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Re: feedback requested on WAI CG Consensus Resolutions on Text alternatives in HTML 5 document

From: Maciej Stachowiak <mjs@apple.com>
Date: Mon, 17 Aug 2009 02:05:14 -0700
Cc: Steven Faulkner <faulkner.steve@gmail.com>, Ian Hickson <ian@hixie.ch>, HTMLWG WG <public-html@w3.org>, W3C WAI-XTECH <wai-xtech@w3.org>
Message-id: <A295631E-6B16-4202-ACC2-83544698D99A@apple.com>
To: Benjamin Hawkes-Lewis <bhawkeslewis@googlemail.com>

On Aug 17, 2009, at 2:00 AM, Benjamin Hawkes-Lewis wrote:

> On 17/08/2009 09:42, Maciej Stachowiak wrote:
>> Would it be appropriate, in light of this, to add a user agent
>> requirement that an img with empty alt should not be mapped to
>> accessibility APIs at all?
>
> Given the variety of authoring practice around "alt", I don't think  
> that would be safe.
>
> In situations like:
>
> <a href="#"><img src="delete.png" alt=""></a>
>
> It's useful to AT for the "img" to be exposed and to be able to  
> access "src" attributes for the purpose of providing a substitute  
> for proper alternative text.

If that's so, then wouldn't it be better for authors to use alt=""  
instead of role="presentation", so that AT can decide whether it needs  
to expose the image anyway? In particular, if your example was marked  
up like this:

<a href="#"><img src="delete.png" role="presentation"></a>

Then isn't it equally necessary and appropriate for AT to expose that  
image?

It seems like, based on this example, images should always be exposed  
to accessibility APIs, and AT should make the call on whether it needs  
to override the author-provided semantics.

> http://www.w3.org/TR/WAI-USERAGENT/guidelines.html#tech-missing-alt
>
> More tendentiously, perhaps, in situations like:
>
> <p>As you can see from the chart below, sales increased in 2008:</p>
> <img alt="" src="chart.png">
>
> Even if users can't consume the chart themselves, it's useful to  
> users to be able to download or hotlink that referenced chart in a  
> collaborative environment (e.g. a corporate wiki).
>
> By contrast:
>
> <img alt="" src="bullet.png">
>
> really is purely decorative; in a collaborative environment that  
> seems likely to be generated by authoring software.

And likewise for these examples - it seems like AT should be left free  
to apply heuristics.

Regards,
Maciej
Received on Monday, 17 August 2009 09:05:57 UTC

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