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

On Thu, 17 Dec 2009 21:09:03 +0100, Leonard Rosenthol <lrosenth@adobe.com>  
wrote:

> 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?

Perhaps, that there are people who prefer programming javascript to  
writing declarative markup.

Since I am not one of those people, I am astounded at the things I see  
people use javascript for in SVG when it could just as well be done with  
declarative code, but I recognise that this is a common enough pattern  
that I am not surprised there is a market for canvas.

More importantly, I think, the shadow DOM required for accessibility is  
*not* a full DOM, it is simply the ability to create the minimal skeleton  
needed to interact with and understand the app - anything decorative  
simply won't appear in the DOM, whereas it does in SVG.

Cheers

Chaals

> 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


-- 
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, 17 December 2009 22:54:34 UTC