- From: Richard Schwerdtfeger <schwer@us.ibm.com>
- Date: Mon, 28 Feb 2011 14:45:55 -0600
- To: chaals@opera.com, Charles Pritchard <chuck@jumis.com>, public-html@w3.org, public-html-a11y@w3.org, public-html-request@w3.org
- Message-ID: <OF5D3EF9D5.D8AAAE1E-ON86257845.00715F4F-86257845.0072111F@us.ibm.com>
Ideally, it would be best to define a collection of drawing calls and bind that to an elements fallback content. When the drawing object changes position or dimensions it would be reflected in the accessible object bound to the drawing object. We think coords would work but it is really heavy weight. Rich Schwerdtfeger CTO Accessibility Software Group From: Richard Schwerdtfeger/Austin/IBM@IBMUS To: Charles Pritchard <chuck@jumis.com> Cc: public-html@w3.org, public-html-a11y@w3.org, chaals@opera.com Date: 02/28/2011 01:18 PM Subject: Re: Content positioning in Canvas fallback content feedback requested Sent by: public-html-request@w3.org Yes. All platform accessibility API provide a bounding rectangle for an Accessible Object. That is why CSS positioning does not quite give us what we want. Consequently, that is why I am suggesting we include allow coordinates to be passed in the canvas subtree. I would like to hear others thoughts on this. Shape is not essential. Rich Schwerdtfeger CTO Accessibility Software Group Inactive hide details for Charles Pritchard ---02/25/2011 05:09:06 PM---On 2/25/2011 2:23 PM, Richard Schwerdtfeger wrote: >Charles Pritchard ---02/25/2011 05:09:06 PM---On 2/25/2011 2:23 PM, Richard Schwerdtfeger wrote: > From: Charles Pritchard <chuck@jumis.com> To: Richard Schwerdtfeger/Austin/IBM@IBMUS Cc: public-html@w3.org, public-html-a11y@w3.org Date: 02/25/2011 05:09 PM Subject: Re: Content positioning in Canvas fallback content feedback requested On 2/25/2011 2:23 PM, Richard Schwerdtfeger wrote: One of the features that platform accessibility API have is bounding rectangles associated with accessible objects. Screen magnifiers use this information to allow the user to zoom to an arbitrary, visual object in view. AI Squared has asked that we provide this feature for the fallback content such that fallback content objects can be positioned, with dimensions relative to where they are drawn on the physical <canvas>. There are a couple of ways we see this can be done: - apply shape and coords similar to image maps in fallback content - Parially, using CSS positioning. Sounds like they want scrollIntoView and getClientRects to work: https://developer.mozilla.org/en/DOM/element.scrollIntoView https://developer.mozilla.org/en/DOM/element.getClientRects Are those the methods they are currently looking at when they receive focus events? Do they set focus prior to zooming into particular objects? ... We use CSS positioning to work with focus management on the last generation of browsers, and pass around getClientRects in our objects (so that we can use DOM or simple JS objects). SVG paths might work in current browsers. Some talk has been going on in the lists about SVG a11y. Partial CSS positioning might violate the notion that the fallback content can be viewed independently of the canvas content. Bounding rectangles would be too small to display text. It's possible that dataTransfer operations might rely on management of fallback content in the future.
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Received on Monday, 28 February 2011 20:46:46 UTC