Fwd: Please vote on the canvas accessibility proposal

forwarded at janinas request

---------- Forwarded message ----------
From: Steven Faulkner <faulkner.steve@gmail.com>
Date: 23 February 2010 13:41
Subject: Re: Please vote on the canvas accessibility proposal
To: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
Cc: Frank Olivier <franko@microsoft.com>, Richard Schwerdtfeger <
schwer@us.ibm.com>, Cynthia Shelly <cyns@exchange.microsoft.com>, Andi
Snow-Weaver <andisnow@us.ibm.com>, "janina@rednote.net" <janina@rednote.net>,
"jongund@uiuc.edu" <jongund@uiuc.edu>, "cooper@w3.org" <cooper@w3.org>,
David Bolter <david.bolter@gmail.com>, "public-html-a11y@w3.org" <
public-html-a11y@w3.org>


Hi Sylvia,

>  - ATs will read content like 'please upgrade your browser' instead of
useful text.

>Where does that come from? Wouldn't they just see the canvas element
>and try to do something useful with it?

This is an example of the sort of content  developers are already including
inside the canvas element. I looked at www.canvasdemos.com I could not
find ANY with fallback (most provided zero fallback) that would be useful
for AT users:


http://concentriclivers.com/slippymap.html
<canvas id="map" width="500" height="500"  onmousedown="mouseDown(event);"
onmousemove="mouseMove(event);"   onmouseup="mouseUp();" onmouseout=
"mouseOut();">Your  browser doesn't support canvas elements.</canvas>
 http://labs.jam3.ca/wp-content/uploads/2010/02/canvasVoxels.html

<canvas id="myCanvas" width="100" height="100">
		Your browser does not support the canvas
	</canvas>
      <audio src="houseofcards.mp3" autoplay="autoplay" loop="2000">
		Your browser does not support the audio element.
	</audio>  		

<http://labs.jam3.ca/wp-content/uploads/2010/02/canvasVoxels.html>

http://www.snappymaria.com/canvas/FunctionPlotter.html
<canvas onmouseout="releaseCanvas();" onmouseup="releaseCanvas();"
onmousemove="slideCanvas(event);" onmousedown="clickCanvas(event);"
height="480" width="640" id="mainCanvas">
It looks like your browser does not support Canvas.
Try FireFox, Chrome, Opera, or Safari instead.
</canvas>

regards
stevef

On 23 February 2010 04:46, Silvia Pfeiffer <silviapfeiffer1@gmail.com>wrote:

> On Tue, Feb 23, 2010 at 3:33 PM, Frank Olivier <franko@microsoft.com>
> wrote:
> > The adom attribute doesn't indicate that the author did a *good* job of
> adding accessible content that will represent the information contained in
> the canvas - no technology or spec text can guarantee that.
> >
> > It merely indicates that the author believes that they have created some
> content that an AT should use.
> >
> > If we don't have the adom attribute:
> >  - Accessibility checkers will not have the ability to programmatically
> scan for compliance.
>
> How so? Wouldn't the content of the canvas be available to any
> program, including a11y checkers?
>
>
> >  - ATs will read content like 'please upgrade your browser' instead of
> useful text.
>
> Where does that come from? Wouldn't they just see the canvas element
> and try to do something useful with it?
>
> Sorry for the dumb questions. Thanks for your help in making me understand.
>
> Cheers,
> Silvia.
>



-- 
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



-- 
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