[Kde-accessibility] focus tracking

[Olaf Schmidt-Wischhöfer]

Hi Jos,

> Ok, thanks all for the responses. A couple of questions if you don't mind,
> to check I understand this properly:
> - AT-SPI does not have a way of tracking focus for magnification purposes?

AT-SPI does have a way to track focus, among a lot of other functionality.

To combine focus tracking with magnification, one needs an application that 
uses an accessibility API such as AT-SPI and that then informs the magnifier 
about the screen area that ought to be highlighted. In the Gnome accessibility 
world this is done by a full-featured screen reader named Orca.

The stable version of AT-SPI is CORBA-based and supported by Gtk, Firefox, 
OO.o and by the Java Accessibility bridge. The current development version
AT-SPI2 is D-Bus-based and aims to make it very easy to support it from Qt 
applications (including the ones from KDE). Proof-of-concept code for Qt 
support already exists, but it needs serious work to be fully functional. Many 
Qt applications will need improved support for the Qt Accessibility bridge 
before focus tracking and other more advanced accessibility features work 
without flaw. (A typical problem will be custom widgets and probably 
Plasmoids.)

> - So Gnome-Mag has developed an API for this, but it's currently CORBA based
> and thus needs changing - apps need to support this API for magnification to
> properly work

The magnification API needs to be supported both by the accessibility aid 
(Orca) and by the magnifier (gnome-mag, kwin, gnome-shell or Compiz).
It would make a lot of sense to use a common API for all these magnifiers.
I see no technical reason against such a cooperation, and I know of no
other reason hindering it, so I expect that when friendly asked, there would 
be interest from all of the various teams to cooperate on this.

For the KDE Plasma Desktop default configuration, it might be possible to 
automatically start a very small tool for simple focus-tracking that disables 
itself once Orca is started. It this tool supports the same magnification API 
as Orca, gnome-mag, kwin, gnome-shell and Compiz, then we get a maximum of 
interoperability.

Olaf