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UAAG-pertinent excerpt from XHTML2 WG face2face minutes

From: Gregory J. Rosmaita <oedipus@hicom.net>
Date: Thu, 28 Feb 2008 17:21:57 +0000
To: w3c-wai-ua@w3.org
Message-Id: <20080228172032.M45148@hicom.net>

LEGEND FOR SNIPPET:
 * Steven is Steven Pemberton of CWI/W3C
 * Roland is Roland Merrick, chair of the XHTML2 WG
 * Shane is Shane McCarron, editor of XHTML Role, Access, M12N, RDFa, etc.
 * Rich is Rich Schwerdtfeger
 * oedipus is GJR (obviously)

<quote  
cite="http://www.w3.org/2008/02/19-xhtml-minutes.html">

<Steven> In css, you say img[src] {content: attr(src)}

<Steven> so in principle you can switch between displaying the image 
and the content

<oedipus> GJR: that "principle" needs to be explicitly stated

<Steven> (but the CSS doesn't give you control over @srctype)

<Steven> In any case the alternate content is in the dom, so is available 
for use as necessary

<oedipus> amen

Steven: poping stack for a few levels, back to "longdesc".

Roland: how we can style both?

Steven: in CSS, content: means replacement with external resource. 
(Steven went to flipchart to argue)

Roland: CSS cannot do fallback at failure.

Steven: *[src]:error, you can invent pseudo-class in that case.
... We don't know it is allowed, but let's assume it allowed...
... *[src]:before
... {content: attr(src)}
... *[src]{display:none}
... body.nosrc *[src] {display:block}
... body.nosrc *[src]:before
... {content: ""}
... *[src]:error

<oedipus> steven, will that {content: "foo";} make it into the DOM? 
currently, CSS-generated text isn't in the DOM and isn't accessible to 
assistive tech

Steven described an error case with src="foo.xdiv" srctype="vide/xdiv"

<oedipus> UAAG (user agent accessibility guidelines WG) is trying to 
address CSS- and script-generated text, UAAG2 has a proposed requirement 
that ALL text, no matter what its source, must be made available via the 
DOM or directly to an accessibility API (such as MSAA, IAccessible2, 
ATK/AT-SPI, etc.

[administrivia clipped]

<Steven> Gregory, wrt your content: question

<oedipus> yeah

<Steven> I didn't put any real content there

<Steven> in one case it is the embedded image

<Steven> in the other case, the embedded image is overwritten with 
'nothing' (empty string)

<Steven> the dom remains the same in both cases

<Steven> (I think)

<Steven> and the DOM contains the URL of the image, and the alternate 
content, both of which reside in the DOM without change

<oedipus> do you think the UAAG2 req unreasonable?

<Steven> and so is accessible to any software that wants to make use 
of it

<oedipus> ok

<Steven> I have no problem with the UAAG2 requirement

<oedipus> that's certainly good to hear

<Steven> In fact it is a pain when you copy a numbered list, and don't 
get the numbers in the copy buffer

<oedipus> the tricky bit is wording it correctly

<Steven> because of the generated content problem

Rich: Guideline for browser for markup?

<oedipus> if CSS is used to control list styling, one doesn't get that 
info from an assistive tech - it uses the "dumb" nesting default 
algorithm

Shane: we provided default CSS for XHMTL2.

<Steven> But for instance Gregory, XForms which also generates content, 
amongst other places via repeats talks of a shadow tree (or DOM)

<Steven> so you have two DOMs

<oedipus> that's the tricky bit UAAG is trying to deal with -- multiple 
DOMs

Shane: Browser people complained "don't constrain browsers".

<oedipus> browser people are always complaining -- just like their 
users!!!

<oedipus> steven, your point about copying content with CSS-generated 
text is a mirror of the AT user's problem, only it is constant, not 
situational

Shane: I have an action item to turn OWL into RDFa.
... at the end of role spec.

<Steven> ack that Gregory

<oedipus> rich, i'm not sure i understand your question -- UAAG 
guideline would be markup agnostic -- if something's writing to the 
visual palette, capture it in the DOM or expose it directly to an 
accessibility API is what UAAG is discussing

</quote>

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Theory helps us to bear our ignorance of fact.
    -- George Santayana, "The Sense of Beauty"
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Gregory J. Rosmaita: oedipus@hicom.net
Camera Obscura: http://www.hicom.net/~oedipus/
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Received on Thursday, 28 February 2008 17:22:11 GMT

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