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RE: hit testing and retained graphics

From: Frank Olivier <Frank.Olivier@microsoft.com>
Date: Mon, 20 Jun 2011 15:57:20 +0000
To: Richard Schwerdtfeger <schwer@us.ibm.com>, "chuck@jumis.com" <chuck@jumis.com>, "Mike@w3.org" <Mike@w3.org>, "david.bolter@gmail.com" <david.bolter@gmail.com>, Cynthia Shelly <cyns@microsoft.com>
CC: "public-canvas-api@w3.org" <public-canvas-api@w3.org>, "public-html-a11y@w3.org" <public-html-a11y@w3.org>, "public-html@w3.org" <public-html@w3.org>
Message-ID: <91175A762AB48840AF1473514B26B4752B03A106@TK5EX14MBXC263.redmond.corp.microsoft.com>
I would leave hit testing up to the (javascript) author. I would recommend that they set existing x,y position, z-index attributes on the DOM objects in the canvas subtree to report what the UI 'looks like' to AT tools. This way, the AT tools don't need to change - this part of the DOM is no different to them than any other part - and authors need to be annotating canvas DOM objects with correct information anyway (labels, aria attributes, etc).

From: Richard Schwerdtfeger [mailto:schwer@us.ibm.com] 
Sent: Friday, June 17, 2011 11:42 AM
To: chuck@jumis.com; Frank Olivier; Mike@w3.org; david.bolter@gmail.com; Cynthia Shelly
Cc: public-canvas-api@w3.org; public-html-a11y@w3.org; public-html@w3.org
Subject: hit testing and retained graphics

Charles, Frank, Mike,

I am back from vacation. How far do we need to go with hit testing? Right now I am looking at associating a closed draw path with a DOM object in the canvas subtree. We would then need to address the routing of pointing device input events to the DOM object. The drawing path can be used to provide bound information to platform accessibility API.

Do we need to bind any other drawing properties to the canvas object - similar to the way device context's are handled on graphic subsystems like Windows?

Mike, I am including you as before I went on vacation you indicated that a number of developers desired this feature and wanted to be involved.

Rich


Rich Schwerdtfeger
CTO Accessibility Software Group
Received on Monday, 20 June 2011 15:58:03 GMT

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