- From: Simon Harper <simon.harper@manchester.ac.uk>
- Date: Thu, 20 Aug 2009 09:09:48 +0100
- To: Jim Allan <jimallan@tsbvi.edu>
- Cc: "'UAWG list'" <w3c-wai-ua@w3.org>
It seems then that the accessibility interface to canvas is the bit we should be working on as canvas seems like a mini-ua? We should start to make suggestions and give solutions to the html5 people IMO. Cheers Si. ======================= Simon Harper University of Manchester (UK) Human Centred Web Lab: http://hcw.cs.manchester.ac.uk My Site: http://hcw.cs.manchester.ac.uk/people/harper/ My Diary (Web): http://hcw.cs.manchester.ac.uk/people/harper/ phpicalendar/week.php My Diary (Subscribe): http://hcw.cs.manchester.ac.uk/diaries/harper/ SimonHarper.ics On 19 Aug 2009, at 18:53, Jim Allan wrote: > Thanks Simon. It's a nice statement. We all know, if a developer > can do > something they will. > > One troubling bit is >> 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. > > UAAG20 has > 3.1.1 Notification of Alternative Content: Provide a global option > for the > user to be notified of alternatives to rendered content (e.g., > short text > alternatives, long descriptions, captions). > > 3.1.2 Configurable Default Rendering: Provide the user with the global > option to set which type of alternative to render by default. If the > alternative content has a different height and/or width, then the > user agent > will reflow the viewport. (Level A) > > We had similar stuff in UAAG10. However no User Agents have yet > implemented > a way to easily get to the internal element "fall back content". > > Another troubling item is >> 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. > > This implies there is separate scripting for canvas. Separate from > javascript? A different instance? How does a user (or agent) turn off > scripting for just canvas? > > Jim > >> -----Original Message----- >> From: w3c-wai-ua-request@w3.org [mailto:w3c-wai-ua-request@w3.org] On > Behalf >> Of Simon Harper >> Sent: Wednesday, August 19, 2009 10:46 AM >> To: UAWG list >> Subject: The Canvas 2D API 1.0 Specification >> >> 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. >> >> ======================= >> >> Simon Harper >> University of Manchester (UK) >> >> Human Centred Web Lab: http://hcw.cs.manchester.ac.uk >> >> My Site: http://hcw.cs.manchester.ac.uk/people/harper/ >> >> My Diary (Web): http://hcw.cs.manchester.ac.uk/people/harper/ >> phpicalendar/week.php >> My Diary (Subscribe): http://hcw.cs.manchester.ac.uk/diaries/harper/ >> SimonHarper.ics >> >> >> >> >> > > >
Received on Thursday, 20 August 2009 08:10:20 UTC