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Re: Accessible interactions with simple switch devices

From: Steve Lee <steve.lee@oucs.ox.ac.uk>
Date: Wed, 17 Nov 2010 10:28:23 +0000
Message-ID: <AANLkTi=NdJD2aWPNV+2G4M7HMsWCAw3mGmJKPpnBQyxq@mail.gmail.com>
To: Doug Schepers <schepers@w3.org>
Cc: public-webevents@w3.org
Thanks Doug

On 16 November 2010 23:12, Doug Schepers <schepers@w3.org> wrote:
> Thanks for writing.  We are just now ramping up the group, so expect to see
> more in the coming weeks.
> Regarding the scope of the group's work items, we have a deliberately narrow
> scope for the charter for 2 reasons:
> 1) We want to stay focused in order to complete the touch and intentional
> events in a timely fashion;
> 2) There is very likely some Intellectual Property around the area of touch
> interfaces, and we are treading very carefully to make sure we can best
> serve all our constituents.

Of course that makes perfect sense. It's just the WG name leads one to
believe it has a wider scope that it actually does for this charter.
Touch is also very relevant to accessibility as it offers alternative
modes of interaction that is often very intuitive.

> So, while it's not possible right now for us to create specific events for
> switch devices, some aspects of those devices should work with the
> high-level abstract "user action" or "intentional" events.  If that should
> prove to be inadequate, we can certainly revisit the issue when our group
> comes up for rechartering in 2012.

OK. Yes if browsers support switch devices the intentional events will
no doubt be useful with suitable Assistive technology providing
interactions. And for now it may be that the effort is best supported
on the operating system or native App Assitive Technology side of the
browser in the stack (though that is then platform specific).

> If you could summarize precisely what problems you ran into when trying to
> adapt a switch interface to DOM events, that would go a long way toward
> making sure we consider that when defining intentional events. It's quite
> possible that support for switches will simply come as a natural consequence
> of the model.

To be specific the issue was to be able to directly access switch
events in a web app. The reson was to allow web apps to directly
support interaction with user of these devices. .

These days switches are usually USB HIDs and appear as joysticks /
games controllers which are not quite 'first class; devices as far as
operating system is concerned. Thus they are not directly support by
most applications, and especially web browsers including the DOM/BOM .
Accordingly the usual approach is to have drivers that map to key or
pointer events or use overlay technology such as OSKs that map in
complex ways. For example see this brand new tutorial from Yahoo!


As we see the headlong rush towards web becoming the platform It would
be excellent to allow these devices to be included to allow innovation
in the space, plus it would provide a better web gaming experience
through joystick support :-).

Switch access via OSKs is incredibly slow and frustrating and needs
innovation. My thoughts are that make this possible in web apps will
reach more users.

Obviously these events would not be use in all web apps but would
allow for innovation and toolkit such as jQuery / Dojo could provide
support as part of the accessibility that they include.

As mentioned above switches appear to be joysticks so the low level
switch event parameters are basically

* Joystick #
* Switch #
* event (on or off)

in this model all logic and timing would then be up to the app to
resolve. Certainly there is room for discussion about the best
approach to handling such devices.

Full Measure
Received on Wednesday, 17 November 2010 10:28:58 UTC

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