Re: Proposal: Canvas accessibility and a media querries approach for alternative content (Action Item 6 in the HTML Accessibility Task Force)

There may be situations where you need entirely different content to do the
work. The scenario suggested would work for 2D graphs but not other things
like a subway map. I provided an example use case in a previous post of the
subway map.

Rich Schwerdtfeger
Distinguished Engineer, SWG Accessibility Architect/Strategist


                                                                           
             raman@google.com                                              
             (T.V Raman)                                                   
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             public-html-reque         singer@apple.com                    
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                                       ian@hixie.ch, Richard               
                                       Schwerdtfeger/Austin/IBM@IBMUS,     
             01/15/2010 01:57          public-canvas-api@w3.org,           
             PM                        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)                              
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           




David,

You've understood things correctly, and the way you phrase it is
exactly the right way to think about fall-back content.

David Singer writes:
 > On Jan 12, 2010, at 14:52 , Ian Hickson wrote:
 > >
 > > I don't understand why we would want, or need, to make the accessible
 > > canvas DOM any different than the regular fallback DOM.
 > >
 >
 >
 > I may be misunderstanding the question, and if so, I apologize.
 >
 > If I have some kind of scientific visualization with controls that I do
in canvas, and there really isn't a way to do that without canvas (i.e. no
real way to draw it), my fallback for browsers not capable of canvas may be
"we regret the loss of picture", whereas my shadow for the accessible user
using canvas may well be a set of controls -- check-boxes ('Gravity
morphing?') sliders ('Phi incursion angle!'), buttons ('fire photon
torpedo!') and so on.
 >
 > If I am right, I would tend to ask the opposite: how can we be sure that
the fallback for non-canvas-capable browsers will essentially always be the
same as the shadow for canvas-capable browsers needing accessible access?
 >
 > David Singer
 > Multimedia and Software Standards, Apple Inc.
 >