Canvas + DOM == SVG? (was FW: ACTION-133: Develop an accessibility API and model for canvas)

If one of the big reasons for pushing Canvas over SVG is that it is "DOM-less" and thus is lighter-weight (and theoretically higher performing) AND if they need to add a DOM (shadow or otherwise) to Canvas for accessibility AND SVG support is already present - why then even bother with Canvas?

What am I missing?

Leonard

From: public-html-request@w3.org [mailto:public-html-request@w3.org] On Behalf Of Paul Cotton
Sent: Thursday, December 17, 2009 12:08 PM
To: public-html@w3.org
Subject: FW: ACTION-133: Develop an accessibility API and model for canvas as well as attributes to specify alternative content

FYI.

Paul Cotton, Microsoft Canada
17 Eleanor Drive, Ottawa, Ontario K2E 6A3
Tel: (425) 705-9596 Fax: (425) 936-7329

From: Richard Schwerdtfeger [mailto:schwer@us.ibm.com]
Sent: Tuesday, December 15, 2009 4:55 PM
To: Paul Cotton
Cc: Maciej Stachowiak; Sam Ruby
Subject: Re: ACTION-133: Develop an accessibility API and model for canvas as well as attributes to specify alternative content


Paul,

At this point the canvas working group is in agreement that we need a shadow DOM with support for ARIA semantics. We have some test samples and we need to get browser support to expose the shadow DOM to the accessibility API.

We are also discussing provisions for alternative renderings triggered via CSS 3 media queries in line with what David Singer is proposing for <video>. The reason for this is that the default canvas UI may be complex enough visually that an alternative presentation may often be necessary to be accessible. What is clear now is that some of the needed properties we would need are absent in the current CSS3 media queries specification as well as the the modalities. It would appear that these CSS properties are also absent in David's proposal. I hope to discuss these issues on this Thursdays call.

Rich


Rich Schwerdtfeger
Distinguished Engineer, SWG Accessibility Architect/Strategist

[cid:1__=09BBFC1EDFFFBB538f9e8a93df938@us.ibm.com]Paul Cotton ---12/15/2009 01:12:46 PM---http://www.w3.org/html/wg/tracker/actions/133
Paul Cotton <Paul.Cotton@microsoft.com>

12/15/2009 01:11 PM


To


Richard Schwerdtfeger/Austin/IBM@IBMUS


cc


Maciej Stachowiak <mjs@apple.com>, Sam Ruby <rubys@intertwingly.net>


Subject


ACTION-133: Develop an accessibility API and model for canvas as well as attributes to specify alternative content








http://www.w3.org/html/wg/tracker/actions/133

This action is due this week. Can you give us a status report? If this will not be done what is a realistic delivery date?

/paulc

Paul Cotton, Microsoft Canada
17 Eleanor Drive, Ottawa, Ontario K2E 6A3
Tel: (425) 705-9596 Fax: (425) 936-7329