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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>

 * 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)


<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 

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 

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

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

<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 

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


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

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