Re: atk <-> MSAA once more

[Peter Korn <Peter Korn Sun COM>]

Hi Allin,

I'm afraid I'm not that expert at MSAA; I left the Windows screen reader 
business before MSAA was released.  However, based on my work on the Java 
Access Bridge for Windows, I'm guessing your going to need to translate a 
Win32 WindowID (and HWND or some such) to the top level GNOME GTK+ object, and 
from there use ATK to get the ATK_Accessible from that GTK+ top-level window. 
 Once you've done that, general code that you'll need to write would create 
proxy MSAA objects for each ATK_Accessible you find, populating it as 
appropriate (based on the sub-interfaces of ATK that are implemented, and 
translating the subset of ATK that MSAA implements).

The initial HWND->GTK+->ATK magic may prove tricky however; and I know nothing 
about the GTK+ port to Windows to help you further...


Regards,

Peter Korn
Sun Accessibility team

Allin Cottrell wrote:
> I'm following up on an issue I raised a few weeks back.  I got busy with 
> other things, but would still like to take a crack at bridging between 
> gtk/atk and MSAA to provide a measure of accessibility for gtk apps on 
> win32.
>
> So far I have made a Windows DLL of libgail (though I'm not quite sure 
> what that buys me) and have done some reading on MSAA.  I'd be grateful 
> if anyone could check my (still vague) understanding of what has to be 
> done.
>
> > From the MS docs, I gather than if Jaws (say) is to read the menus 
>
> from a gtk appplication, it proceeds by asking OLEACC to quiz the app.  
> OLEACC sends a WM_GETOBJECT message to the "server" (e.g. the gtk app).  
> The server either returns zero (in which case OLEACC attempts to 
> construct a proxy), or it returns an "Iaccessible object".  I'm 
> supposing that if the gtk app returns zero, OLEACC is not going to make 
> much headway trying to construct a proxy, since the app is not composed 
> of standard Windows controls.  Therefore (?), the app will have to build 
> and return an Iaccessible object.
>
> I can sort of see from the MS docs how one might go about constructing 
> an Iaccessible object.  What I'm very hazy on is how one would hook this 
> up with atk/gail.  Or how one would receive and recognize OLEACC's 
> WM_GETOBJECT message in the first place.
>
> Would this involve (something like) creating an intermediary process 
> which would listen for WM_GETOBJECT, and with which one's gtk app would 
> be "registered" in some way.  Is this roughly what gail does on gnome 
> (or is it at-spi that does that)?
>
> Sorry for all the questions.  It may be that I'm simply out of my depth 
> here, but I'm still keen to try if I can get a better handle on what's 
> required.
>
> Allin Cottrell
> Department of Economics
> Wake Forest University, NC
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