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Re: [css3-content] [css21-content] Syntax for adding alternative text for inserted image

From: Benjamin Hawkes-Lewis <bhawkeslewis@googlemail.com>
Date: Fri, 3 Dec 2010 00:53:52 +0000
Message-ID: <AANLkTi=qaDw8+rx7YxzGoFx6V24PqP=KFRcMTOTNA149@mail.gmail.com>
To: Boris Zbarsky <bzbarsky@mit.edu>
Cc: CSS 3 W3C Group <www-style@w3.org>
On Sun, Nov 28, 2010 at 10:11 AM, Benjamin Hawkes-Lewis
<bhawkeslewis@googlemail.com> wrote:
> On Sat, Nov 27, 2010 at 2:41 AM, Boris Zbarsky <bzbarsky@mit.edu> wrote:
>> On 11/26/10 2:40 AM, Benjamin Hawkes-Lewis wrote:
>>>
>>> But note in WAI-ARIA's "Text Alternative Computation" algorithm:
>>
>> This isn't exactly the first time WAI specs are ... somewhat divorced from
>> reality (in this case, by introducing a direct conflict with CSS2.1, as you
>> note).

FYI PFWG have responded to the issues I logged with them:

http://lists.w3.org/Archives/Public/public-pfwg-comments/2010OctDec/0017.html

Note proposed updates to the algorithm at:

http://www.w3.org/WAI/PF/aria/20101202/roles#namecalculation

"Text nodes are often visited because they are children of an element
that uses rule 2C to collect text from its children. However, because
it is possible to specify or alter textual content using CSS rules, it
is necessary for user agents to combine such content, as appropriate,
with the text referenced by the text nodes to produce a complete text
alternative. An example is the use of CSS :before and :after
pseudo-elements, where the user agent combines the textual content
specified in the style sheet with that given in the DOM.

   "* When an image replaces text, then the UA should use the original
text, since that text is presumably the equivalent.
   "* When text replaces an image, then the UA should provide that text.
   "* When new text replaces old, then the UA should include the new
text, since that is what is rendered on screen.

"Note: Though a user agent may make efforts to compute a text
alternative from CSS-generated text in the absence of text content
determinable from the DOM, authors should not provide text through a
style sheet, as a user agent may incorrectly determine the text
alternative."

--
Benjamin Hawkes-Lewis
Received on Friday, 3 December 2010 00:54:25 GMT

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