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Re: Discussion: Text Alternative Survey

From: Laura Carlson <laura.lee.carlson@gmail.com>
Date: Sat, 24 Apr 2010 13:23:54 -0500
Message-ID: <i2y1c8dbcaa1004241123p2e414dc3y28e7da5439716a01@mail.gmail.com>
To: Ian Hickson <ian@hixie.ch>
Cc: Dave Singer <singer@apple.com>, Matt Morgan-May <mattmay@adobe.com>, HTML Accessibility Task Force <public-html-a11y@w3.org>
Hi Ian,

>> > It violates layering by making it possible for removal of ARIA to
>> > affect conformance,
>>
>> Ian, could you explain this further? I did not attend the WAI CG
>> sessions when the ARIA options were added. We should have solid
>> rationale for the options listed. If layering is a problem, let's try to
>> figure it out here.
>
> Layering isn't a problem, it's an architectural design principle.
>
> ARIA is, by design, a layer above HTML (initially HTML4 and XHTML1) that
> adds annotations for ATs.

Is the principle argument relevant? Layering is not mentioned in the
HTML Design Principles [1]. The HTML working group never came to any
consensus on  the Design Principle document. Separation of concerns is
a principle found in the Design Principles document. But that seems to
be violated by adding the new interactive elements.

> To use it, one takes a conforming HTML document
> and adds ARIA to make it accessible.
>
> By definition therefore, removing ARIA can't make a document
> non-conforming. A proposal that would allow for a document to be written
> with ARIA such that removing the ARIA makes the document non-conforming is
> thus suffering from what we call a "layering violation".

In practical terms, in this case, how does a "layering violation" make
a difference?

>> >  discourages use of semantic HTML by removing the
>> >  allowance for using title="" for titles,
>>
>> Using title="" is problematic as it cannot be relied upon as alt can.
>> It is only safe to use for extra, advisory information.
>
> The point here is that there is no alt, because the author doesn't know
> what the image is. The spec is describing ways of giving the image's title
> or caption. If the image _did_ have alternative text, then it would be
> appropriate to give the title in the title="" attribute. What the spec is
> doing here is saying that in the case where there is no alt="" attribute,
> you can still give the title in the title="" attribute, and the UA/AT is
> expected to use that information.

I think I understand the reasoning behind "images whose contents are
not known" section now. That has baffled me for the longest time. It
is an attempt to  mitigate damages. Right?

The missing attribute has the same goal. If we can figure that out it
might resolve much of this issue.

>> > and encourages longer markup than necessary by suggesting the use of
>> > role="presentation" to imply alt="" when alt="", which is shorter,
>> > already implies role="presentation".
>>
>> This is a good point, Ian. Shorter is usually better. The current
>> rationale states:
>> "role="presentation" programmatically conveys to assistive technology
>> that an image is presentational and not of interest."
>
> Empty alt="" does the exact same thing. In fact it literally implies ARIA
> role="presentation" by definition. An <imp> with empty alt="" is in the
> "presentation" role whether the author says it explicitly or not.

Does anyone have rationale why we need "role="presentation"? Can
anyone not live with it not being one of the options in the list?

Best Regards,
Laura
[1] http://www.w3.org/TR/html-design-principles/
-- 
Laura L. Carlson
Received on Saturday, 24 April 2010 18:24:26 GMT

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