- From: Richard Schwerdtfeger <schwer@us.ibm.com>
- Date: Thu, 19 Nov 2009 14:12:59 -0600
- To: Frank Olivier <franko@microsoft.com>
- Cc: Steven Faulkner <faulkner.steve@gmail.com>, 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>
- Message-ID: <OFE02B56B4.FFDC8D1D-ON86257673.006EFFF0-86257673.006F0D7E@us.ibm.com>
yep. I got all that.
Rich Schwerdtfeger
Distinguished Engineer, SWG Accessibility Architect/Strategist
Frank Olivier
<franko@microsoft
.com> To
Sent by: Richard
public-canvas-api Schwerdtfeger/Austin/IBM@IBMUS,
-request@w3.org Steven Faulkner
<faulkner.steve@gmail.com>
cc
11/19/2009 11:47 James Craig <jcraig@apple.com>,
AM "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] 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
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.stev
e@gmail.com>
Sent by: To
public-canvas-
api-request@w3 James Craig
.org <jcraig@appl
e.com>
11/17/2009 cc
04:56 AM
public-canva
s-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
regards
Stevef
2009/11/16 James Craig <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 | www.wat-c.org
Web Accessibility Toolbar -
http://www.paciellogroup.com/resources/wat-ie-about.html
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Received on Thursday, 19 November 2009 20:13:51 UTC