Re: Please vote on the canvas accessibility proposal

Rich Schwerdtfeger
Distinguished Engineer, SWG Accessibility Architect/Strategist

Silvia Pfeiffer <silviapfeiffer1@gmail.com> wrote on 02/25/2010 07:02:40
PM:

> Silvia Pfeiffer <silviapfeiffer1@gmail.com>
> 02/25/2010 07:02 PM
>
> To
>
> Richard Schwerdtfeger/Austin/IBM@IBMUS
>
> cc
>
> Steven Faulkner <faulkner.steve@gmail.com>, Ian Hickson
> <ian@hixie.ch>, public-canvas-api@w3.org, "public-html-a11y@w3.org"
> <public-html-a11y@w3.org>, public-html-a11y-request@w3.org
>
> Subject
>
> Re: Please vote on the canvas accessibility proposal
>
> On Fri, Feb 26, 2010 at 2:19 AM, Richard Schwerdtfeger
> <schwer@us.ibm.com> wrote:
> >
> > Silvia, For the 12th time now. adom is not a statement of
accessibility. It
> > simply says to use the subtree as the accessibility mapping as intended
by
> > the author. It is NOT  A COMPLIANCE STATEMENT. It is a way for
theauthor to
> > associate their subtree of canvas as their accessibility implementation
of
> > canvas.
>
> Sorry, but if people that have held discussions with your for weeks
> still do not understand your meaning about @adom, how is a Web
> developer supposed to?
>
> Also, if I have understood the previous discussion correctly, then
> everything that is inside the <canvas> is already by definition both
> accessibility and fallback markup. There is no distinction being made
> between the two. Any subtree inside the <canvas> is already associated
> as an accessibility implementation of canvas.
>
> Anyway - maybe it makes sense to provide some explicit examples of the
> use of @adom and how it will make a difference to the interpretation.
> I think concrete markup will expose the use case more than any
> argument will.
>
>
> > I need you and Ian to point me to the text in the proposal that makes
the
> > claim you are both making.
>
> I am not making any claims. I am asking questions and making logical
> deductions from the answers I am getting.
>

It would be better if you had read the proposal and not the Ian chatter..

>
> >> accessibility. What if the Web developer thinks they have made the
> >> subtree accessible, but have in fact forgotten to add aria attributes
> >
> > What if they forget to do this in the areamap example? What if they
forget
> > to do this elswhere in the document?
>
> There is no markup elsewhere in HTML claiming there is accessibility
> information available for an element. The claim that accessibility
> information is available should not be made by the Web developer, but
> by a user or a tool that checks for accessibility markup.
>
>
Again. I will take a different tactic with the proposal. It is clear that
whenever accessibility is referred to it is
a compliance statement.

> > Ian's example was a non-interactive picture on the web page. This about
the
> > most trivial accessibility issue to address. Are you trying to tell
everyone
> > that <canvas> is going to be used to create non-interactive pictures
most of
> > the time? If that is the case I would suggest dumping it from HTML 5.
>
> No, I also stated that Ian's picture was simple and that there are
> probably others where there is tighter integration between the
> accessibility data inside the <canvas> and the <canvas> itself. Please
> read my replies fully.
>
>
> >> I think a tool that needs to evaluate whether something is accessible
> >> cannot rely on an attribute but has to do the hard work of actually
> >> walking through the DOM tree and identifying whether there is actual
> >> effort done in providing accessibility markup.
> >>
> > Exactly, and it needs to know what part of the web page to test. That
is all
> > adom is doing for the test tool.
>
> But ... the part that it needs to test is inside the <canvas> element.
> There is no need to express where it is. I really don't follow.
>
> Honestly, do provide some example markups that show the difference
> that the element makes. Thus far it's all theoretical and one cannot
> have factual discussions about theories, only theological ones.
>
There are examples on the canvas api discussion list posted by Apple,
Microsoft, IBM, and the University of Illinois.
If you would read those you would not be making assumptions about the basis
for peoples statements.

Rich
>
> Best Regards,
> Silvia.