Re: handling focus

does the proposed solution mean that a method to hide 'fallback' will be
required?

<canvas>
shadow dom elements

<fallback>
your browser does not support canvas
</fallback>
</canvas>

regards
steve
2009/11/19 Richard Schwerdtfeger <schwer@us.ibm.com>

>  yep. I got all that.
>
>
> Rich Schwerdtfeger
> Distinguished Engineer, SWG Accessibility Architect/Strategist
>
> [image: Inactive hide details for Frank Olivier ---11/19/2009 11:50:17
> AM---We discussed this at the HTML 5 Canvas accessibility breako]Frank
> Olivier ---11/19/2009 11:50:17 AM---We discussed this at the HTML 5 Canvas
> accessibility breakout session. The two main reasons for creating a way to
> draw an ‘OS
>
>
>     *Frank Olivier <franko@microsoft.com>*
>             Sent by: public-canvas-api-request@w3.org
>
>             11/19/2009 11:47 AM
>
>
> To
>
> Richard Schwerdtfeger/Austin/IBM@IBMUS, Steven Faulkner <
> faulkner.steve@gmail.com>
> cc
>
> James Craig <jcraig@apple.com>, "public-canvas-api@w3.org" <
> public-canvas-api@w3.org>, "public-canvas-api-request@w3.org" <
> public-canvas-api-request@w3.org>, Alexander Surkov <
> surkov.alexander@gmail.com>
> Subject
>
> RE: handling focus
>
> We discussed this at the HTML 5 Canvas accessibility breakout session.
>
> The two main reasons for creating a way to draw an ‘OS styled’ focus
> rectangle was:
> (1) The user gets to see the focus rectangle drawn in the correct ‘big
> yellow border/high contrast’ style (if the user set their display to be in
> black-on-white/white-on-black/big yellow focus rectangle high contrast mode)
> (2) If the user is zooming the screen using a magnifier, the user agent can
> tell the OS where focus is inside the canvas; the magnifier can then pan to
> the correct location on the screen.
>
>
> *From:* public-canvas-api-request@w3.org [
> mailto:public-canvas-api-request@w3.org <public-canvas-api-request@w3.org>]
> *On Behalf Of *Richard Schwerdtfeger*
> Sent:* Tuesday, November 17, 2009 5:57 AM*
> To:* Steven Faulkner*
> Cc:* James Craig; public-canvas-api@w3.org;
> public-canvas-api-request@w3.org; Alexander Surkov*
> Subject:* Re: handling focus
>
> Steve,
>
> Excellent point. So what you really want is the ability to set the focus
> location in the visual canvas which then translates to an accessibility API
> mapping. I was concerned that you were going to try and effect the drawing
> on the visual canvas. That would not work as the developer would not
> appreciate it.
>
> The only way to do this would be to bind a rectangle to the shadow DOM
> object. ATs will be doing an objectFromPoint, etc. on the focusable object.
> We would need some script to set the "visible" rectangle on the Shadow DOM
> object. Where the visible rectangle actually refers to the object in the
> canvas with focus.
>
> Rich
>
>
> Rich Schwerdtfeger
> Distinguished Engineer, SWG Accessibility Architect/Strategist
>
> [image: Inactive hide details for Steven Faulkner ---11/17/2009 04:57:20
> AM---Hi James,]Steven Faulkner ---11/17/2009 04:57:20 AM---Hi James,
>
>
>       *Steven Faulkner <faulkner.steve@gmail.com>*
>                         Sent by: public-canvas-api-request@w3.org
>
>                         11/17/2009 04:56 AM
>
>    To
>
> James Craig <jcraig@apple.com>
> cc
>
> public-canvas-api@w3.org
> Subject
>
> Re: handling focus
>
>
>
> Hi James,
>
> >In the shadow DOM proof of concept I developed, I just drew the focus ring
> with the canvas. I don't see any need to have a native focus ring drawn on
> top of >the canvas. I'd say, leave a custom view like canvas for the author
> to manage.
>
> How do AT such as screen magnifiers provide focus highlighting of
> interactive parts of the canvas if native focus is not provided?
> How are they able to follow and bring currently focused elements into the
> viewport if there focus is not programmatically exposed provided?
> I consider a solution that does not satisfy the following section 508
> criteria [1] as inadequate and have yet to see any proposal that satisfies
> this:
>
> § 1194.21 Software applications and operating systems.
> (c) A well-defined on-screen indication of the current focus shall be
> provided that moves among interactive interface elements as the input focus
> changes. The focus shall be programmatically exposed so that assistive
> technology can track focus and focus changes.
>
> [1] *http://www.section508.gov/index.cfm?FuseAction=Content&ID=12#Software
> * <http://www.section508.gov/index.cfm?FuseAction=Content&ID=12#Software>
>
> regards
> Stevef
> 2009/11/16 James Craig <*jcraig@apple.com* <jcraig@apple.com>>
>
>    On Nov 16, 2009, at 5:27 AM, Steven Faulkner wrote:
>
>       > at TPAC the provision of a method to draw focus rectangles on a
>       canvas was discussed, and it appeared that this was considered necessary,
>
>       In the shadow DOM proof of concept I developed, I just drew the
>       focus ring with the canvas. I don't see any need to have a native focus ring
>       drawn on top of the canvas. I'd say, leave a custom view like canvas for the
>       author to manage.
>
>       > how does this fit in with the use of active-descendent to track
>       focus in a shadow DOM?
>
>       Only using 'active-descendant' would allow for a shadow DOM as deep
>       as one managed focus widget. This is fine, but a standard focus model inside
>       the shadow DOM is necessary, too. Otherwise you'd need to render a separate
>       canvas element for every complex widget, so something as complex as Bespin
>       could never be achieved by using a single active descendant.
>
>
>
>
> --
> with regards
>
> Steve Faulkner
> Technical Director - TPG Europe
> Director - Web Accessibility Tools Consortium*
> **
> **www.paciellogroup.com* <http://www.paciellogroup.com/> | *www.wat-c.org*<http://www.wat-c.org/>
> Web Accessibility Toolbar - *
> http://www.paciellogroup.com/resources/wat-ie-about.html*<http://www.paciellogroup.com/resources/wat-ie-about.html>
>
>


-- 
with regards

Steve Faulkner
Technical Director - TPG Europe
Director - Web Accessibility Tools Consortium

www.paciellogroup.com | www.wat-c.org
Web Accessibility Toolbar -
http://www.paciellogroup.com/resources/wat-ie-about.html