W3C home > Mailing lists > Public > public-html@w3.org > July 2009

Re: Helping Canvas Tag Be Accessible

From: Anne van Kesteren <annevk@opera.com>
Date: Thu, 30 Jul 2009 19:05:19 +0200
To: "Richard Schwerdtfeger" <schwer@us.ibm.com>
Cc: "Steven Faulkner" <faulkner.steve@gmail.com>, "HTML WG" <public-html@w3.org>, "W3C WAI-XTECH" <wai-xtech@w3.org>
Message-ID: <op.uxv4e5go64w2qv@annevk-t60>
On Thu, 30 Jul 2009 18:11:25 +0200, Richard Schwerdtfeger <schwer@us.ibm.com> wrote:
> Actually, we provide the ARIA role="presentation" on a table used for
> layout and you are done. It is actually quite trivial. There is no need  
> in most cases to provide an elaborate style sheet unless there is some  
> reason the author can't use tables to meet their need.

I'm arguing not abusing tables has become simpler, you're saying the opposite. Interesting. I don't think encouraging <table role=presentation> is the right idea though. We should encourage people to use CSS for layout. (And yes, it would be nice if the CSS WG was quicker with defining flex/grid layouts.)


> Note: just be cause you provide the API does not mean that the author  
> needs to implement them in all cases. Again, all we are doing is providing  
> tools to the author.

If you're talking about the supposed accessibility API for <canvas> here the case where the author does not use it would be a loss for accessibility. I'm saying that might be the majority case and that it might therefore be better to provide people with tools at the right level of abstraction. Using CSS instead of presentational markup was just an example.

But before we start drafting an accessibility API for <canvas> I think we ought to study use cases a bit more and figure out what authors actually want. E.g. authors of advanced Web applications want a generic programmable low-level accessibility API rather than one that is DOM-based (WAI-ARIA) or built on top of <canvas>:

  http://rossboucher.com/2009/03/01/limitations-of-the-wai-aria/

That makes sense to me, although from what the examples he cited only Bespin is hard to make accessible and it is completely unclear whether applications such as Bespin need to use <canvas> in a few years.

My main point is that I think we're way too quick to argue that "<canvas> is inaccessible and here is how you solve it". We need to carefully consider what people are doing with <canvas>, what authors want, whether they might use such an API at all, etc.


-- 
Anne van Kesteren
http://annevankesteren.nl/
Received on Thursday, 30 July 2009 17:06:09 UTC

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