- From: Greg Lowney <gcl-0039@access-research.org>
- Date: Tue, 09 Feb 2010 15:23:20 -0800
- To: WAI-UA list <w3c-wai-ua@w3.org>
- Message-ID: <4B71EE68.4090805@access-research.org>
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 > > > > >
Received on Tuesday, 9 February 2010 23:25:44 UTC