W3C home > Mailing lists > Public > public-canvas-api@w3.org > April to June 2010

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

From: Richard Schwerdtfeger <schwer@us.ibm.com>
Date: Mon, 17 May 2010 08:54:12 -0500
To: Frank Olivier <franko@microsoft.com>
Cc: "Cynthia Shelly" <cyns@microsoft.com>, "david.bolter@gmail.com" <david.bolter@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>, "surkov.alexander@gmail.com" <surkov.alexander@gmail.com>
Message-ID: <OFA59A53EC.3C028420-ON86257725.006F55BF-86257726.004C5FBE@us.ibm.com>
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? Since Frank's mappings make use of MSAA, which you use with IA2, 
it should work fine.

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 Schwerdtfeger
CTO Accessibility Software Group

Frank Olivier <franko@microsoft.com> 
Sent by: public-canvas-api-request@w3.org
05/11/2010 01:48 PM

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>

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 
.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 

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:


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 

Best Regards,

Rich Schwerdtfeger
CTO Accessibility Software Group
Received on Monday, 17 May 2010 14:13:11 UTC

This archive was generated by hypermail 2.4.0 : Friday, 17 January 2020 19:10:26 UTC