Re: Please vote on the canvas accessibility proposal

Rich Schwerdtfeger
Distinguished Engineer, SWG Accessibility Architect/Strategist

public-canvas-api-request@w3.org wrote on 02/24/2010 04:34:14 PM:

> Ian Hickson <ian@hixie.ch>
> Sent by: public-canvas-api-request@w3.org
>
> 02/24/2010 04:34 PM
>
> To
>
> Richard Schwerdtfeger/Austin/IBM@IBMUS
>
> cc
>
> public-canvas-api@w3.org, "public-html-a11y@w3.org"
<public-html-a11y@w3.org>
>
> Subject
>
> Re: Please vote on the canvas accessibility proposal
>
> On Wed, 24 Feb 2010, Richard Schwerdtfeger wrote:
> > >
> > > > It also does not mean it is accessible if you are saying the canvas

> > > > can only act as a bitmap.
> > >
> > > I don't see how something that "conveys essentially the same function

> > > or purpose", when presented to the user, can be anything _but_
> > > accessible.
> >
> > You are saying that it has the same function as the "bitmap" canvas. I
read
> > this as having the function of a bitmap.
>
> The bitmap canvas is the image rendered by the <canvas> element in visual

> media.
>
>
> > Also, fallback content could provide similar function (essentially the
> > same) but that does not mean the same function of the canvas as it is
> > rendered.
>
> Indeed. But we still have to expose it to the user.
>
You can when <canvas> is not being rendered.
>
> > So, if what you are saying is true most or a vast majority of canvas
> > implementations are in non-compliance.
>
> Assuming you mean pages that use <canvas>, and not <canvas>
> implementations, then yes -- most aren't accessible. It's a terrible
state
> of affairs, that won't be helped by making it even harder to get
> accessibility right by adding an unintuitive attribute that has to be
> added in order for the fallback content to be accessible.
>
The proposal does not state that. adom says use what is in the subtree as
the authors implementation of the accessible canvas. It also does not say
that is what is in the subtree is fallback content at the time it is set to
true.

I think I am repeating myself for the 11th time now. adom is not a
compliance statement like it is pixie dust. How does adom state that
"fallback content" is accessible in the proposal? Where does it say that it
is always fallback content?

To be honest. All you seem to be doing is bring up the same irrelevant
comments.

>
> > img alt is the most simplistic example and only conveys the text
> > equivalent aspect of accessibility. If you know <canvas> behaves like
an
> > image or bitmap then that would be a good start. If you go to something

> > like bespin, which is not a bitmap then we have a problem.
>
> Bespin is a great demo, but it's a horrible misuse of <canvas>.
>
You can say that but it does not make it go away.
>
> > Perhaps we are arguing semantics but clearly the current wording has
not
> > helped to promote accessible canvas development.
>
> I doubt many authors have read the current wording. Adding attributes
that
> make getting this right even more complicated certainly isn't going to
> help matters, IMHO.
>
> --
> Ian Hickson               U+1047E                )\._.,--....,'``.    fL
> http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
> Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'
>