[orca-list] ATK vs iaccessible2 (again)

[Bill Cox <waywardgeek gmail com>]

I know Willie has answered this is the past: moving to iaccessible2 is
a bad idea.  However, I've been reading a bit about it, so I thought
I'd bring it up again.

So far as I can tell, iaccessible2 is the Windows interface to
Firefox, Adobe Acrobat, and Qt applications like Skype.  This
interface gets hammered every day by JAWs users, and bugs get fixed at
a better rate than what we can do.  Willie and the ATK guys were
involved in iaccessible2 development, so that it could encompass most
of what's needed by both Windows and Gnome.  However, it still falls
short in several areas which are documented here:

http://www.linuxfoundation.org/collaborate/workgroups/accessibility/iaccessible2/overview#Comparison_to_the_UNIX_ATK

In reality, these limitations in iaccessible2 aren't very important,
IMO.  Programmer's don't set image descriptions, and bugs in GTK+ keep
us from hearing them anyway, while imates through iaccessible2 are
often described by JAWs.  Programmers never add a label relationship
between a checkbox and other controls in a treeview, which may be why
you never hear the checkbox toggle.  There are rich aspects to ATK
still not found in iaccessible2.  However, iaccessible2 works better
with WAI-ARIA, which includes the Firefox model of JavaScript
controls.  These things are still fairly broken in Orca/ATK.  The
iaccessible2 interface to FireFox is solid, as it gets hammered every
day by thousands of users.  Iaccessible2 has more controls, and some
ARIA widgets, and possibly Qt widgets, are hard to model in ATK.

Qt has a dbus interface, since qt4.3, though I can't figure out how to
enable it!  So, the default plan, which no one is working on as far as
I can tell, is to write an iaccessible2 to ATK converter.  That way,
Orca can continue to work as-is without modification, and we'll get
some support for Qt apps like Skype, and maybe Adobe Acrobat Reader.
I assume we'll continue to interface to Firefox throught their buggy
and poorly maintained ATK interface, and continue to work with Gnome
applications through the buggy ATK widget interface.  We can fix bugs,
so we can make this work.

However, what would happen if instead, we wrote an ATK to iaccessible2
converter, and switched Orca over to the somewhat modified dbus
interface?  Would that allow us to switch to the iaccessible2
interface to Qt, Firefox, and Adobe Acrobat with fewer problems?  Or,
do we really beleive that ATK encompasses iaccessible2 more easily
than the other way around?

If we could get on the iaccessible2 bandwagon, we could benefit from
all the Windows bug fixing, and also help consolidate support for the
standard.  As is, iaccessible2 is nothing more than a non-Microsoft
Windows accessibility API.

What do you think?
Bill