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Re: HTML Canvas 2D Context API change proposal for magnifier focus and caret/selection tracking

From: David Bolter <david.bolter@gmail.com>
Date: Mon, 17 May 2010 13:45:59 -0400
Message-ID: <4BF180D7.7040909@gmail.com>
To: Richard Schwerdtfeger <schwer@us.ibm.com>
CC: Frank Olivier <franko@microsoft.com>, Cynthia Shelly <cyns@microsoft.com>, "janina@rednote.net" <janina@rednote.net>, "mike@w3.org" <mike@w3.org>, "mjs@apple.com" <mjs@apple.com>, Canvas API <public-canvas-api@w3.org>, "public-canvas-api-request@w3.org" <public-canvas-api-request@w3.org>, HTML Accessibility Task Force <public-html-a11y@w3.org>, "surkov.alexander@gmail.com" <surkov.alexander@gmail.com>
Hi Rich,

Thanks for driving this -- I know it has been a slog as we are all busy 
(and perhaps unsure of the right solution). Just a few 
comments/questions inline:

On 17/05/10 9:54 AM, Richard Schwerdtfeger wrote:
> Thank you for the quick response Frank. I have fixed the typo.
> David, Alex,  Does the accessibility API mapping and this approach work
> for you?

I don't see any show stoppers but we haven't dug into implementation. 
The main concerns I have is actual browser implementation and author 
>   Since Frank's mappings make use of MSAA, which you use with IA2,
> it should work fine.

I'm not sure what the 'mappings' refer to? Franks' implementation notes 
regarding caretBlinkRate and setCaretSelection make sense to me.

Did you catch Alexander's questions from May 12th?

> Maciej, will these 2D Context API changes work for Apple? I tried to make
> sure that the API changes would support selection tracking on Macs. If you
> could respond I would appreciate it. I sent the first draft of this to
> Apple on April 11 and received no feedback. Since then the changes have
> been editorial. I am doing my best to not have accessibility be a barrier
> to HTML 5 getting through last call.
> At this point the NoNav attribute for the<canvas>  element has passed
> through the accessibility tools task force. The combination of this change
> with nonav should address canvas accessibility. Charles has a change to
> canvas that would allow an image map to be used as the accessible fallback
> content for<canvas>. For many instances this may be easier than nonav.
> Either scenario would require this proposal.
> Best regards,
> Rich
> Rich Schwerdtfeger
> CTO Accessibility Software Group
> Frank Olivier<franko@microsoft.com>
> Sent by: public-canvas-api-request@w3.org
> 05/11/2010 01:48 PM
> To
> Richard Schwerdtfeger/Austin/IBM@IBMUS, "david.bolter@gmail.com"
> <david.bolter@gmail.com>, "surkov.alexander@gmail.com"
> <surkov.alexander@gmail.com>, "janina@rednote.net"<janina@rednote.net>,
> "mike@w3.org"<mike@w3.org>, "mjs@apple.com"<mjs@apple.com>, Canvas API
> <public-canvas-api@w3.org>, "public-canvas-api-request@w3.org"
> <public-canvas-api-request@w3.org>, HTML Accessibility Task Force
> <public-html-a11y@w3.org>, "'Maciej Stachowiak'"<mjs@apple.com>, "Cynthia
> Shelly"<cyns@microsoft.com>
> cc
> Subject
> RE: HTML Canvas 2D Context API change proposal for magnifier focus  and
> caret/selection tracking
> .caretBlinkRate() can be wired up to GetCaretBlinkTime in Windows. See
> http://msdn.microsoft.com/en-us/library/ms648401(VS.85).aspx
> .setCaretSelection can be wired up to SetCaretPos; MSDN has some good
> documentation on this.
> SetFocus() http://msdn.microsoft.com/en-us/library/ms646312(VS.85).aspx
> can be used for focus management for .drawFocusRing; one approach would be
> to use a child window at the x,y coordinates.
> Typo:>/p>  in the setCaretSelectionPos(element, x, y) steps section.
> From: Richard Schwerdtfeger [mailto:schwer@us.ibm.com]
> Sent: Monday, May 10, 2010 1:43 PM
> To: david.bolter@gmail.com; surkov.alexander@gmail.com; Frank Olivier;
> janina@rednote.net; mike@w3.org; mjs@apple.com; Canvas API;
> public-canvas-api-request@w3.org; HTML Accessibility Task Force; 'Maciej
> Stachowiak'; Cynthia Shelly
> Subject: Re: HTML Canvas 2D Context API change proposal for magnifier
> focus and caret/selection tracking
> I would like to have all user agent developers to please provide
> feedback/changes they would like to see made to the proposal by Monday so
> that I may make any necessary changes to the final draft for May 24, 2010
> to submit for a straw pole vote on May 27 in the HTML accessibility task
> force.
> Frank Olivier is going through the proposal with a fine tooth comb and
> will submit feedback on Thursday in terms of how these changes will map to
> the Windows accessibility API. These simple changes can all be made in
> MSAA as I see it so they will also be applicable to Firefox. That said, I
> would like both David and Alex to review the comments from Frank and
> submit them to the list. There seems to be a gap on Linux that we may need
> to fill. I am not aware of an ATK API to have a magnifier track the caret
> screen position. This may need to be added.
> As for Apple I would ask Maciej to look the changes and say if it can be
> mapped in some way to the Mac OSX accessibility protocol either now or in
> the future and if there are any changes that need to be made to the
> proposal. I plan on wrapping this up next week.
> Frank indicated that the HTML working group may wish to tweak the API or
> API parameter names. Personally, that is not an issue for me as long as
> they are well documented which given the feedback I have as of today the
> changes made the API modifications clearer. Changes reside between<ZZ>
> and</ZZ>
> I know the HTML working group would like to wrap this all up quickly so I
> urge you all to review and provide feedback in the requested time frame.
> Here is the proposal with the attached changes in HTML format:
> http://lists.w3.org/Archives/Public/public-canvas-api/2010AprJun/0021.html
> There will be no Canvas Accessibility API meeting on Monday, May 17, 2010
> as I am traveling but I will have access to email and look forward to your
> feedback.
> Best Regards,
> Rich
> Rich Schwerdtfeger
> CTO Accessibility Software Group
Received on Monday, 17 May 2010 17:46:44 UTC

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