W3C home > Mailing lists > Public > public-respimg@w3.org > August 2012

RE: Adaptive Image Element Proposal

From: Adrian Roselli <Roselli@algonquinstudios.com>
Date: Thu, 30 Aug 2012 13:18:24 +0000
To: Leif Halvard Silli <xn--mlform-iua@xn--mlform-iua.no>
CC: HTML WG <public-html@w3.org>, "public-respimg@w3.org" <public-respimg@w3.org>
Message-ID: <0CB063710346B446A5B5DC305BF8EA3E262E41@Ex2010MBX.development.algonquinstudios.com>
Comments within...

> -----Original Message-----
> From: Leif Halvard Silli [mailto:xn--mlform-iua@målform.no]
> Sent: Thursday, August 30, 2012 8:53 AM
> ]] In order to fall back gracefully, the alt attribute and its
>    value should be repeated on the child img element. [[
> 3 comments regarding img as child of picture
> (1) To repeat oneself is an antipattern. In my view, it should be considered
> valid if the <img> does not contain any @alt as long as it instead points, via
> aria-labelledby="", to the picture element:
> <picture alt="Alernative text" id="pict" >  <img src=file aria-labelledby="pict"
> /> </picture>

I believe this fallback is for browsers that will not support the <picture> element. Not to levy an attack against IE usage, but IE 6-9 usage is not exactly zero, and IE10 may be out before this is supported. In that case, the <img> element is the only thing that will be recognized and so the redundancy is necessary.

The ARIA attribute is meaningless in that case since the browser won't pull it from an element it doesn't know.

> (2) Also, if the picture element is the content of an figure element with a
> figcaption, then the img should not need to contain the alt attribute. (This
> may not need to be said - perhaps HTML5 already cover
> this.)

Again, this presumes the browser supports HTML5's <figure> and <figcaption> element, which older browsers do not (and will not).

> (3) If the picture is presentational (has empty alt), then the img, if any, would
> need to have empty alt as well.

If I am reading this correctly, you want the spec to state that an @alt value of blank should be repeated on the <img>. If so, the wording already says that. The spec says to match the value, and blank is still a value.

> But other than that, then I think an <img> as child of <picture> needs to be
> conformance checked/authors as if the <picture> element did not exist.
> In bug 18384 [2], we discuss other ways to provide fallback. Perhaps those
> methods should be reserved to situations when picture is given, by the
> author, another role than "img" or "presentation" - e.g. if it has 'document'
> role. Thus, it may be necessary to specify further rules about the fallback so
> that the fallback is not used in ways which are inconsistent with its role as
> alternative text.

This is where I wonder if @longdesc was ignored prematurely.
Received on Thursday, 30 August 2012 13:18:58 UTC

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