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Re: Example canvas element use - accessibility concerns

From: Alexander Surkov <surkov.alexander@gmail.com>
Date: Wed, 18 Feb 2009 23:26:07 +0800
Message-ID: <faf3cb2b0902180726re3fa11em718b74c5b25bdfb8@mail.gmail.com>
To: Robin Berjon <robin@berjon.com>
Cc: Philip Taylor <pjt47@cam.ac.uk>, Steven Faulkner <faulkner.steve@gmail.com>, HTML WG <public-html@w3.org>, W3C WAI-XTECH <wai-xtech@w3.org>, Janina Sajka <janina@rednote.net>
> Well the canvas text API gets text in, so it's possible that one could get
> text out.

I thought about that. I believe it's possible. It should be good for
simple cases but not for Bespin case because they draw caret,
selection - it means they should fire proper a11y events to AT - I
don't realize the way how to implement this.

Alex Surkov.


On Wed, Feb 18, 2009 at 11:16 PM, Robin Berjon <robin@berjon.com> wrote:
> On Feb 18, 2009, at 15:52 , Philip Taylor wrote:
>>
>> The main problem I see with adding built-in (as opposed to bolt-on)
>> accessibility to canvas is that I can't even begin to imagine any way that
>> could ever possibly work at all :-). That may be largely because my
>> imagination is limited - I'd be interested in concrete suggestions of how it
>> could be done. Otherwise I can't think of anything the spec could say to
>> help accessibility here.
>
> Well the canvas text API gets text in, so it's possible that one could get
> text out. The problem is: in what order. There are various heuristics that
> could be used (the order in which it's drawn, its rendered distance from the
> origin, or other more elaborate approaches). I'm not saying it's ideal, or
> even the right thing to do, but there certainly is information being
> provided by the developer to the canvas API that could be exposed to AT.
>
> There could, furthermore, be additional
> pushAnnotation(string)/popAnnotation() calls added to the API that could
> provide alternative text information about what is being painted. Again, I'm
> not sure that that's a good idea, I'm just indicating that there /might/ be
> options.
>
> Since Bespin is designed largely as an experiment (even if it is meant to
> continue) it might just be the right place/occasion to have such
> discussions.
>
> At first thought I would tend to consider that a good first step would be to
> write an authoring guide providing guidance as to when to use canvas and
> when to use something else.
>
> --
> Robin Berjon - http://berjon.com/
>    Feel like hiring me? Go to http://robineko.com/
>
>
>
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Received on Wednesday, 18 February 2009 15:26:48 GMT

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