Re: hit testing and retained graphics

On Thu, Jul 7, 2011 at 10:38 AM, Charles Pritchard <chuck@jumis.com> wrote:
> On 7/7/2011 10:07 AM, Doug Schepers wrote:
>> 1) Make AT that is is "smart" enough to identify an important shape, zoom
>> in on it, and track it if it is moving (this seems like a hard problem, but
>> wouldn't need any changes to specs);
>
> As rendering engines push more into the graphics card, ATs have less
> opportunity to apply direct heuristics to the screen.
> Also, these are computing devices; forcing vision recognition for virtual
> components is a last resort. It's slow, too.

Agreed that image recognition is not a solution we should care about
right now, given that it's an AI-hard problem.  Given sufficient
hardware and software increases, though, it will arrive as a useful
solution eventually (and will, eventually, solve *all* accessibility
problems).  ^_^


>> 2) Make the shape, size, and position information available through a
>> special accessibility API, updated and maintained in parallel to changes to
>> the rendered shape;
>
> This API already exists (with shape as an exception); it's the accessibility
> tree and its implemented by most vendors as a separate
> tree which is updated when changes are made to the DOM tree.

This is incorrect.  Size and position are *not* drawn from the
accessibility subtree.  All three pieces of information that Doug
listed have to be explicitly indicated by the author in your proposal.

(I could see a solution where this isn't the case, and the DOM
actually *does* act as a form of scene graph, but that probably
requires a new context to be written.  It's also remarkably similar to
Doug's proposal to put Canvas in SVG.)

~TJ