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[Bug 18384] Consider adding an adaptive image element

From: <bugzilla@jessica.w3.org>
Date: Tue, 24 Jul 2012 14:10:24 +0000
Message-Id: <E1Stfoe-00006j-VN@jessica.w3.org>
To: public-html-a11y@w3.org
https://www.w3.org/Bugs/Public/show_bug.cgi?id=18384

Leif Halvard Silli <xn--mlform-iua@xn--mlform-iua.no> changed:

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--- Comment #4 from Leif Halvard Silli <xn--mlform-iua@xn--mlform-iua.no> 2012-07-24 14:10:24 UTC ---
(1) Proposal:  Perhaps someone should file a separate bug to track the
accessibility of <picture>?

(2) To reuse @alt would have backward compatibilty issues for AT tools. How? 
     FIRSTLY: Today @alt is only supported on a finite number of elements. And,
frankly, it is only supported (quite) well on the <img> elemetn. (It is not at
all supported that well on <area> and <input> - I could mention a numnber of
issues.) Even screenreaders do - at least in theory - only look for @alt on
elements where they know that it ought to exist. 
     SECONDLY: If instead we use mark-up as fallback/alternative text, the -
until support is there - one can use @aria-describedby and @aria-labelledby in
order to point to the fallback. By contrast, if one went for @alt, then the
only way to be backward compatible would be by duplicating the @alt content
with an @aria-label - like so: <picture alt="alternativ text"
aria-label="alternative-text" >... </picture>

(In reply to comment #2)

> <picture role="img">
> 
> <p>alt text</p>
> 
> <source srcset="small.jpg 1x, small-highres.jpg 2x">
> <source media="(min-width: 18em)" srcset="med.jpg 1x, med-highres.jpg 2x">
> <source media="(min-width: 45em)" srcset="large.jpg 1x, large-highres.jpg
> 2x">
> <img src="small.jpg">
> 
> </picture>


> I can understand that backwards compatibility may be of concern in the
> first example, but that can be resolved through the use of CSS to clip or
> hide text content if so desired.


Is it not as simple as setting  

    <p>alt text</p>

to
    <p style="display:none">alt text</p>

?

Keep in mind that whenever one do <foo role="img">, then the content of <foo>
is considered hidden from AT *anyway*. For an <foo role=img>, then one *MUST*
use an @aria- attribute in order to hold or point to the accessible text. *OR*
one must use an attribute (such as @alt) and - perhaps?- even an element that
is especially designated for alterantive text.

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Received on Tuesday, 24 July 2012 14:10:31 GMT

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