Re: Created ACTION-280 - Write flash or canvas fallback content use case for intent for GL3

It seems like OBJECT and CANVAS elements, and their respective fallback 
content, are handled exactly the same, so I'm not sure why we duplicate 
all the discussion and examples rather than giving them once and saying 
they apply to OBJECT, CANVASS, and any others we can think of. If we 
were to keep them separate and provide separate sets of examples (in the 
case below, two for Flash but only one for Canvas) that could give the 
impression that there is a fundamental difference between how we expect 
UA to handle the two types of content.

It's good for examples to include what we consider to be recommended 
methods, or best practices. In this case, we probably want to recommend 
that UA provide user options to replace specific types of content with 
their fallback content (e.g. do it for Flash, but not for all images). 
We probably also want to recommend that the presence of fallback content 
be indicated to the user through the same mechanisms that are used for 
other types of alternative content (e.g alt, or longdesc); is putting an 
actionable element (e.g. an icon) after the rendered primary content 
(e.g. image, or flash) our recommendation? Doing so would of course 
raise the dreaded spectre of forcing content to reflow, with all that 
entails. Alternatives that avoid reflowing include a distinctive border 
around the element, or possibly providing an actionable element which is 
drawn overlapping the primary content. Overlapping indicators could be 
similar to the small arrow which Windows overlays onto an icon to 
indicate that it's a shortcut to something, or might take the form of a 
border that's drawn within the boundary of the element rather than 
outside it (thus again avoiding having to potentially reflow the 
content). Might be worth at least mentioning those as possible 
implementations. Also if the UA provides a context menu for actions 
available on an element, we should probably recommend that include any 
commands to select and display one form of the element's alternative 
content.

-------- Original Message  --------
Subject: Created ACTION-280 - Write flash or canvas fallback content use 
case for intent for GL3
From: Jim Allan <jimallan@tsbvi.edu>
To: 'UAWG list' <w3c-wai-ua@w3.org>
Date: 2/9/2010 12:26 PM
> Use Case Flash (OBJECT with fallback content)
> User has a browser with Flash enabled. A webpage has Flash content (OBJECT
> element) which is inaccessible to the user. The author has included
> 'fallback content' within the OBJECT element. 
> 1. The user disables flash content using browser UI controls and the
> fallback content becomes perceivable and usable. 
> 2. The user agent detect fallback content within the OBJECT. The browser
> inserts an actionable element (e.g. an icon) after the OBJECT. When the user
> activates the icon the fallback content opens in a new window, or appears in
> place of the primary OBJECT content.
>
> Use Case CANVAS (with fallback content)
> A webpage has CANVAS content which is inaccessible to the user. The author
> has included 'fallback content' within the CANVAS element. 
> 1. The user agent detect fallback content within the CANVAS. The browser
> inserts an actionable element (e.g. an icon) after the CANVAS. When the user
> activates the icon the fallback content opens in a new window, or appears in
> place of the CANVAS.
>
> HTML5 Definition of FALLBACK CONTENT
> http://www.w3.org/TR/html5/embedded-content-0.html 
>
> 3.2.5.1.6 Embedded content
>
> Embedded content is content that imports another resource into the document,
> or content from another vocabulary that is inserted into the document.
>
>     * audio
>     * canvas
>     * embed
>     * iframe
>     * img
>     * math
>     * object
>     * svg
>     * video
>
> Elements that are from namespaces other than the HTML namespace and that
> convey content but not metadata, are embedded content for the purposes of
> the content models defined in this specification. (For example, MathML, or
> SVG.)
>
> Some embedded content elements can have fallback content: content that is to
> be used when the external resource cannot be used (e.g. because it is of an
> unsupported format). The element definitions state what the fallback is, if
> any.
>
> Jim Allan, Accessibility Coordinator & Webmaster
> Texas School for the Blind and Visually Impaired
> 1100 W. 45th St., Austin, Texas 78756
> voice 512.206.9315    fax: 512.206.9264  http://www.tsbvi.edu/
> "We shape our tools and thereafter our tools shape us." McLuhan, 1964
>
>
>
>
>