- From: Richard Schwerdtfeger <schwer@us.ibm.com>
- Date: Fri, 22 Jan 2010 16:36:15 -0600
- To: Maciej Stachowiak <mjs@apple.com>
- Cc: Steven Faulkner <faulkner.steve@gmail.com>, Ian Hickson <ian@hixie.ch>, public-canvas-api@w3.org, public-canvas-api-request@w3.org, HTML WG <public-html@w3.org>
- Message-ID: <OFA326703C.C6816E4A-ON862576B3.005E5580-862576B3.007C2B42@us.ibm.com>
Rich Schwerdtfeger Distinguished Engineer, SWG Accessibility Architect/Strategist public-canvas-api-request@w3.org wrote on 01/20/2010 06:39:19 AM: > Maciej Stachowiak <mjs@apple.com> > Sent by: public-canvas-api-request@w3.org > > 01/20/2010 06:39 AM > > To > > Steven Faulkner <faulkner.steve@gmail.com> > > cc > > Ian Hickson <ian@hixie.ch>, public-canvas-api@w3.org, HTML WG > <public-html@w3.org> > > Subject > > Re: Proposal: Canvas accessibility and a media querries approach for > alternative content (Action Item 6 in the HTML Accessibility Task Force) > > > On Jan 20, 2010, at 4:21 AM, Steven Faulkner wrote: > > > Hi Ian, > > > > >The click fires on the <canvas>, and the script is responsible for > > >propagating the click to the link to cause the navigation (the UA has no > > >idea that it corresponds to the <a>, so it can't happen automatically). > > > > so if the script propagates the click to the link element, it > would seem that the content of the canvas element should no longer > be considered 'fallback' as interaction and resulting actions are > routed through the a element in the canavas element for all users > not only those with disabilites. > > If you're using the contained DOM children as a model/controller in > this way, then indeed, it's not just 'fallback'. It becomes a way of > building your application logic in a way that also makes it very > easy to expose to assistive technologies. Doing it that way is an > option, however, not a technical requirement. You could just as > easily just assign window.location to navigate, in this example. > > > > > >On the other hand, if the user hits enter while the link is focused, the > > >event goes to the link and the UA does the navigation automatically. > > > > so if the link is focused and the user clicks on the region within > the focus rectangle then the click will pass to the link without the > need for the script? > > According to what Ian said, that won't happen. > > Furthermore, objects in a canvas need not be rectangular and in > general can be all sorts of funny shapes. While a rectangle might be > the best approximation we can do for focus purposes, it would not be > appropriate to force that restriction for hit testing. Not only > that, but visual objects in the canvas can stack, and knowing their > focus rectangles alone does not tell you the z-order, so even hit > testing of purely rectangular objects might not work right (z-order > might not match logical order and therefore might not be the order > in which things appear in the hidden/fallback/model DOM. Yes, both are true. The script for processing the canvas must manipulate the shadow DOM and perform the actions. That is fine. > > Regards, > Maciej > >
Received on Friday, 22 January 2010 22:36:55 UTC