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canvas and accessibility Re: consensus and last call

From: Charles McCathieNevile <chaals@opera.com>
Date: Thu, 25 Jun 2009 16:24:10 +0200
To: "David Singer" <singer@apple.com>, "HTMLWG WG" <public-html@w3.org>
Message-ID: <op.uv23mkpbwxe0ny@esws31067.es.deloitte.com>
On Thu, 25 Jun 2009 15:45:01 +0200, David Singer <singer@apple.com> wrote:

> At 12:23  +0100 24/06/09, Steven Faulkner wrote:

>> There is nothing hypothetical about the inaccessibility of canvas
>> content and accessible design is a cornertsone of W3C philosophy, so I
>> would suggest that unless it is resolved before October, it would
>> contribute to a delay.
> I (personally) feel that I should be spending more time on this issue  
> (accessibility of canvas) but in the limited time that I have scratched  
> my head over it, the result has been not much more than a few more  
> scratch marks.  If you have ideas, or want to chat about it, I'll try to  
> lend my ears...

There was a discussion about it in the PF working group a couple of weeks
ago. I would be happy to be involved in further discussion - along with
the same deep grooves you will be wearing in your head, my thoughts run
along the lines of building something like an ARIA tree as part of what
happens inside the canvas. It's not entirely clear how to navigate this
tree visually - you need associations with bits of the canvas perhaps, or
maybe authoring guidelines tha explain that you need to pick up on
navigation by that tree and respond to it.

But that would at least provide a mechanism by which authors who wanted to
could make something better than an entire alternative, becaus it would be
part of the code that controls the canvas already.

This is essentially authoring guidelines, rather than anything automated,
but canvas is for script authors - a step more complex than SVG and
therefore a step harder to generalise with easy-fit solutions. And it's
about as close as I can see to a solution (since "create a complete
alternative" isn't a solution to making canvas accessible, it's just a
reason to avoid it altogether - and that won't happen).

> [Mind you, the couple of times I have talked about debating the  
> structure of how to address media accessibility, which also needs work,  
> I have had no response. ... Can anyone hypothesize why my attempts to  
> start a discussion on this topic have gone nowhere?]

It's a really complicated topic, a lot of people have little to no
experience of media accessibility and how it works (especially once you go
beyond obvious things like captions), different people are interested in
different topics, and the HTML WG might have hundreds of people in it but
that's not a very big pond but it does have a serious risk of promoting

Those are just hypotheses. Not necessarily very good ones...



Charles McCathieNevile  Opera Software, Standards Group
       je parle français -- hablo español -- jeg lærer norsk
http://my.opera.com/chaals       Try Opera: http://www.opera.com
Received on Thursday, 25 June 2009 14:24:58 UTC

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