Re: X.Org work on accessibility

[Bill Haneman <Bill Haneman Sun COM>]

Hi Brandt:

(This discussion might be better suited to gtk-devel-list gnome org 
I have cross-posted there, please reply to only one or the other)

There is ongoing work in GTK in exactly this area, and I am active in 
working out the architecture.  At the moment there is a toolkit layer, 
"ATK", which will be implemented on/by GTK+ widgets in GTK+-2.0.  This 
is a C binding to accessibility properties for UI widgets, abstracting 
their state and properties for presentation to assistive technologies.  
Since ATK is "in process", the ATK abstraction layer will be bridged to 
an "out of process" service provider interface (The Gnome Accessibility 
SPI, now called "GAEL" for Gnome Accessibility Enabling Library).

ATK has no explicit GTK+ dependencies, though GTK+ does depend on it.  I 
have had preliminary discussions with KDE/Qt developers, and one 
possibility being discussed is that Qt widgets could use ATK for their 
accessibility support, and thus both GTK+ and Qt could use the same 
"bridge" to the common SPI.  Alternatively, KDE/Qt can provide their own 
toolkit-appropriate framework and bridge it to the common SPI.  
Similarly, the Java Accessibility API will be bridged on linux/solaris 
to this SPI, providing transparent accessibility support for Java 
applications in the same way as GTK+ apps.  Similar bridges can be built 
for OpenOffice toolkits, gecko, and any other toolkits that coexist on 
the desktop (yes, even Motif if you want ;-).

The current plan is for the SPI to use CORBA as its IPC implementation, 
but we will provide a library of C bindings for use by assistive 
technologies so that vendors will not have to deal with CORBA directly 
if they don't want to.

The current status and roadmap:  ATK is soon to be uploaded to GNOME 
CVS, in time for GTK+-2.0 freeze.  An external, dynamically loadable 
module which contains the actual implementations of ATK on various 
widgets is in development and will be packaged with GNOME 2.0.  The SPI 
is still taking shape, though we would like very much to have its 
architecture and API in place within a few weeks.

Have a look at 
http://developer.gnome.org/projects/gap
for more information on the project.

We'd love to hear from you and hope that we can work together to make 
ATK, and even more importantly, GAEL, applicable to and usable by the 
widest range of applications and toolkits.  Without a standard 
accessibility framework for the desktop, we cannot achieve a high degree 
of accessibility across a wide range of *nix desktops.  (Note that ATK 
and SPI are not dependent on X, and there is no fundamental reason why 
cross-toolkit accessibility support should be tied to X).

Best regards,

Bill


>
>Greetings,
>
>I am leading a task force on accessibility (to information technology,
>for persons with disabilities) in X.Org, the "standard bearer" of the X
>Window System.  We have recently begun to discuss adding support at the
>Xlib layer (approximately) to permit toolkits to expose an interface
>that would enable, e.g., screen readers and other forms of assistive
>technology to be developed for applications built on X.  Currently we
>have an implementation that is (too) specific to Motif, and we would
>like (a) to re-specify it in a toolkit neutral manner, and (b) foster
>adoption by toolkit developers.  (That's an oversimplification, but
>adequate for now.)
>
>So I'm writing to you, virtual hat in virtual hand, to ask whether
>anyone out there has interest in pursuing this in any form, and whether
>there's already work going on in accessibility related to toolkits such
>as GTK.
>
>Although I'm leading this work in X.Org, I see it as having relevance 
to
>anyone building toolkits on the X Windows platform.  I'd like to
>identify all those interested in participating (at any level) in this
>development, or, if a similar effort is already well underway within 
the
>GNOME or GTK communities, I'd like to get connected to it.  Any advice,
>pointers, etc., would be appreciated.
>
>Let me leave you with a couple of relevant pointers:
>
>X.Org homepage at: http://www.x.org
>
>(Now moribund) Disability Action Committee for X:
>http://trace.wisc.edu/world/computer_access/dacx/
>
>An interesting paper on X-Windows accessibility:
>http://trace.wisc.edu/docs/x_win_disability/x_disabl.htm
>
>Best regards,
>/Brant Cheikes
>
>
------
Bill Haneman x19279
Gnome Accessibility / Batik SVG Toolkit
Sun Microsystems Ireland