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Re: Request for advice on <canvas> accessibility

From: Ian Hickson <ian@hixie.ch>
Date: Thu, 9 Jul 2009 23:09:51 +0000 (UTC)
To: W3C WAI-XTECH <wai-xtech@w3.org>, HTMLWG WG <public-html@w3.org>
Cc: James Craig <jcraig@apple.com>, Steven Faulkner <faulkner.steve@gmail.com>, Joshue O Connor <joshue.oconnor@cfit.ie>, Catherine Roy <ecrire@catherine-roy.net>, Debi Orton <oradnio@gmail.com>, Gez Lemon <gez.lemon@gmail.com>, Jason White <jason@jasonjgw.net>, John Foliot <foliot@wats.ca>, Laura Carlson <laura.lee.carlson@gmail.com>, Leif Halvard Silli <lhs@malform.no>, "Patrick H. Lauke" <redux@splintered.co.uk>, Philip TAYLOR <p.taylor@rhul.ac.uk>, Robert J Burns <rob@robburns.com>, Roger Johansson <roger@456bereastreet.com>, Shelley Powers <shelleyp@burningbird.net>, Steve Faulkner <sfaulkner@paciellogroup.com>
Message-ID: <Pine.LNX.4.62.0907092302480.23663@hixie.dreamhostps.com>
On Fri, 26 Jun 2009, James Craig wrote:
> 
> I, admittedly, haven't thought about this problem in depth, but it seems 
> that canvas (or any DOM element for that matter) could be special-cased 
> to allow a programmatic representation of the data displayed, along with 
> an any relevant accessibility information and interaction methods. I 
> have no ideas for how to make this "automatic" like you request, but I'm 
> sure we can come to a reasonable solution that would allow 
> accessibility-conscious authors to make their canvas-based applications 
> accessible.

On Sat, 27 Jun 2009, Joshue O Connor wrote:
> 
> Good stuff Ian. It will be great for us to get our heads together and 
> work this one out. It is a fantastic challenge and opportunity for 
> closer collaboration :-)

How can I help? I really don't know how to approach this problem, and I 
really would like the input of the WAI groups on this matter. Is there 
some way to follow the WAI's work on this? What is the process by which 
the WAI can provide advice on such topics?


On Sat, 27 Jun 2009, Steven Faulkner wrote:
> 
> I would suggest 3 things:
> 
> 1. For a problem that has stumped you we need as much technical 
> expertise as is possible, so have included the HTML WG in this email.

Oops; I intended to do so, my apologies.


> 2. we use an example that embodies the problem: 
> http://people.mozilla.com/~jdicarlo/piemenus.html contains 2 examples of 
> UI controls rendered using canvas.

I'm certainly happy to look at other cases also. The main reason I 
suggested the HTML5 issues list graph:

   http://www.whatwg.org/issues/data.html

...is that it isn't a demo, so if there is anything that can be done to 
make it accessible, I'd like to do that, so that the graph is actually 
more accessible.


> 3. rephrase the question:  what would need to be added to the canvas API 
> so that the UI controls in the example could have programmtic focus 
> (like an area on an image map) and name, role and state information 
> exposed to accessibility APIs, without expecting the author to 
> completely recreate the UI controls in HTML.

I think this is definitely one of the things that would need addressing, 
yes.

-- 
Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'
Received on Thursday, 9 July 2009 23:10:30 UTC

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