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The Canvas 2D API 1.0 Specification

From: Simon Harper <simon.harper@manchester.ac.uk>
Date: Wed, 19 Aug 2009 16:46:01 +0100
Message-Id: <ED628671-A300-4500-A131-7C0E3B703433@manchester.ac.uk>
To: UAWG list <w3c-wai-ua@w3.org>
I was monitoring xtech and saw this going through

http://dev.w3.org/html5/canvas-api/canvas-2d-api.html


which says..

5. Accessibility Considerations

Authors should not use the canvas interface element in a document  
when a more suitable element is available. For example, it is  
inappropriate to use a canvas interface element to render a page  
heading: if the desired presentation of the heading is graphically  
intense, it should be marked up using appropriate elements (typically  
h1) and then styled using CSS and supporting technologies such as XBL.

When authors use the canvas interface element, they must also provide  
content that, when presented to the user, conveys essentially the  
same function or purpose as the bitmap canvas. This content may be  
placed as content of the canvas interface element. The contents of  
the canvas interface element, if any, are the element's fallback  
content.

In interactive visual media, if scripting is enabled for the canvas  
interface element, the canvas interface element represents an  
embedded element with a dynamically created image.

In non-interactive, static, visual media, if the canvas interface  
element has been previously painted on (e.g. if the page was viewed  
in an interactive visual medium and is now being printed, or if some  
script that ran during the page layout process painted on the  
element), then the canvas interface element represents embedded  
content with the current image and size. Otherwise, the element  
represents its fallback content instead.

In non-visual media, and in visual media if scripting is disabled for  
the canvas interface element, the canvas interface element represents  
its fallback content instead.



they say...

Techniques and additional APIs to make specific uses of canvas  
interface elements more widely accessible are under discussion, and  
will be reflected in this draft as progress is made.

I wonder what these are?


Cheers
Si.

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Simon Harper
University of Manchester (UK)

Human Centred Web Lab: http://hcw.cs.manchester.ac.uk

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Received on Wednesday, 19 August 2009 15:46:39 GMT

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