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Re: Request for review of alt and alt value for authoring or publishing tools

From: Steven Faulkner <faulkner.steve@gmail.com>
Date: Wed, 16 Apr 2008 09:01:56 +0100
Message-ID: <55687cf80804160101t9f6d06aje914c268a2aaf9ae@mail.gmail.com>
To: "James Graham" <jg307@cam.ac.uk>
Cc: public-html@w3.org, "John Foliot" <foliot@wats.ca>, "Tomas Caspers" <tomas@tomascaspers.de>, wai-xtech@w3.org, wai-liaison@w3.org

hi graham,
> Can you give an example of the differences in behavior you would expect?


If a screen reader encounters an <img alt="" noalt>
instead of ignoring the image if it is <img> or <img alt=""> as it
does now (in most circumstances) it could simply announce the presence
of the graphic as it does now:
<img alt="useful text"> announces "graphic useful text"

 <img alt=""> or <img> announces nothing

future:
<img alt="useful text"> announces "graphic useful text"

<img alt="" noalt> announces "graphic"

<img> announces nothing

<img alt=""> announces nothing


By announcing the presence of the graphic (a cue), the user is alerted
that the image may contain important information, this could result in
the user paying closer attention to to graphic, for example,
increasing magnification if they are using a magnifier, to see if they
can discern anything from the pixels
or asking somebody to explain to them what the image is.

Screen magnifiers could add a border around the image to indicate that
it may be of interest. thus providing a visual cue for the user.



regards
stevef


On 15/04/2008, James Graham <jg307@cam.ac.uk> wrote:
> Steven Faulkner wrote:
> >
> > > There is *absolutely no practical difference* to the UA between omitting
> > > the alt="" attribute altogether, and having the alt="" attribute set to
> > > some magical reserved value. They are functionally identical, and user
> > > agents can get as much information from either.
> > >
> >
> > No. you are wrong.
> >
> > if <img alt=""> signals to an AT that an image can be safely ignored
> > (which is current usage).
> > then <img noalt> could signal that image should not be ignored by AT
> > <img> signals that neither can the image safely be ignored or that it
> > should not be ignored as it may contain something important.
> >
>
> I think this makes the incorrect assumption that a UA will be able to make a
> useful distinction between the @noalt case and the missing alt attribute
> case. In practice @noalt will end up on images that should have alt=""
> (because e.g. of developers misunderstanding the spec) and images that
> should not be ignored will have neither @alt nor @noalt. Therefore in the
> absence of an alt attribute or in the presence of a noalt attribute, the UA
> should do its level best to supply some useful information about the image,
> hopefully using something better than the crummy "read the filename"
> algorithm that AT vendors have employed to date.
>
> Can you give an example of the differences in behavior you would expect?
>
> --
> "Mixed up signals
> Bullet train
> People snuffed out in the brutal rain"
> --Conner Oberst
>


-- 
with regards

Steve Faulkner
Technical Director - TPG Europe
Director - Web Accessibility Tools Consortium

www.paciellogroup.com | www.wat-c.org
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Received on Wednesday, 16 April 2008 08:02:35 GMT

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