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Re: hit testing and retained graphics

From: Benjamin Hawkes-Lewis <bhawkeslewis@googlemail.com>
Date: Sun, 3 Jul 2011 09:18:28 +0100
Message-ID: <CAEhSh3fACzYEWi=4hTH6LuBBBR_m8kDz8jwX8LCobh=REVMA_w@mail.gmail.com>
To: Charles Pritchard <chuck@jumis.com>
Cc: Steve Faulkner <faulkner.steve@gmail.com>, Henri Sivonen <hsivonen@iki.fi>, Sean Hayes <Sean.Hayes@microsoft.com>, "E.J. Zufelt" <everett@zufelt.ca>, Paul Bakaus <pbakaus@zynga.com>, "Tab Atkins Jr." <jackalmage@gmail.com>, John Foliot <jfoliot@stanford.edu>, Charles McCathieNevile <chaals@opera.com>, Richard Schwerdtfeger <schwer@us.ibm.com>, Cameron McCormack <cam@mcc.id.au>, Cynthia Shelly <cyns@microsoft.com>, "david.bolter@gmail.com" <david.bolter@gmail.com>, Frank Olivier <Frank.Olivier@microsoft.com>, "Mike@w3.org" <Mike@w3.org>, "public-canvas-api@w3.org" <public-canvas-api@w3.org>, "public-html@w3.org" <public-html@w3.org>, "public-html-a11y@w3.org" <public-html-a11y@w3.org>
On Sun, Jul 3, 2011 at 3:32 AM, Charles Pritchard <chuck@jumis.com>
>>> I don't see why you would have to duplicate the whole accessibility
>>> stack  to provide focus tracking for a screen magnifier, can you
>>> explain this a bit further?
>> The remote system access server would need to translate the remote
>> applications (as accessed by the accessibility tree plus custom
>> hooks) into DOM. To support custom views/controls for which we do not
>> have semantics in the web stack or to provide any
>> application-specific customizations, local AT would have to make
>> special interpretations of the DOM (either directly or as exposed to
>> the accessibility API). Thus, the accessibility stack (converting
>> remote applications into accessible interfaces) would need to be
>> duplicated.
>> If you disagree, can you explain precisely what you think the remote
>> system access server on the one hand, and local AT on the other,
>> would need to do?
> They can limit their protocol to sending information to elements which
> gain focus, for high-latency/bandwidth constrained environments;

Doesn't detecting the size and position of the focused object require
the remote access server to inspect the accessibility tree *plus custom

> they could enable a protocol along websockets which allows them to
> pass platform specific commands for Accessibility tree queries (such
> as Microsoft's UIA or Apple's UIAutomation);

Do you mean commands issued by client AT?

Doesn't detecting the size and position of the focused object require
the client AT to send commands to inspect the accessibility tree *plus
custom hooks*?

> arbitrary amount of introspection and heuristics.

That's a bit hand-wavy!

Benjamin Hawkes-Lewis
Received on Sunday, 3 July 2011 08:19:09 UTC

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