Re: [g-a-devel] Allowing assistive technologies to work with touch gestures.

[Luke Yelavich <luke yelavich canonical com>]

Please keep the CC in tact, this is a cross-list discussion.

On Mon, Nov 12, 2012 at 03:40:02PM EST, Jason White wrote:
> Luke Yelavich <luke yelavich canonical com> wrote:
>  
> > My initial thought is to implement some form of hand-off process, where an
> > assistive technology like Orca can request to take over control of gesture
> > processing at the root X window. This would require a desktop environment
> > that requires root X window gesture processing priority to register with an
> > arbitrator that manages who has access to the root X window for gesture
> > processing.  Orca would then register with the same arbitrator, and request
> > to be handed control of gesture processing, and possibly be given a pointer
> > to the relinquishing environments' code to allow for further gesture
> > processing to take place for the environment, if the gesture used is not one
> > that Orca listens for.
> > 
> > Since this is for assistive technologies, and given that at-spi is the
> > defacto standard for GUI environment accessibility on GNOME/Unity/QT, I
> > propose that this arbitrator could be added to at-spi. Its slightly outside
> > at-spi's scope, but any desktop environment that wishes to offer
> > accessibility will have this service running in the background, and I don't
> > see the point in writing another daemon to run in the user session just for
> > this arbitration process.
> 
> If I remember rightly, AT-SPI 2 already handles keyboard events (including the
> synthesis of keyboard input), so there is a precedent within the existing
> infrastructure for the above proposal.

Yes, it does.

> It would also be prudent to consider the implications of the anticipated move
> by desktop environments from X to Wayland for the proposal. We don't want
> accessibility infrastructure developers to be scrambling to catch up when a
> widely used desktop environment makes that transition, since it is known well
> in advance that this is likely to happen.

I plan to extend orca to use the geis interface, so it at least will not be exposed to that transition, at least from a touch point of view.

Luke