Re: Gnopernicus

[Bill Haneman <bill haneman sun com>]

On Thu, 2002-08-22 at 15:28, Richard Schwerdtfeger wrote:
> 
> Hi Bill,
> 
> I understand that there are problems with the Linux X-server implementation
> that prohibit magnification. Would you please detail me the changes needed
> to support magnification that are implemented on Solaris systems.

Hi Rich:

Well, that issue is somewhat outdated; we've gone ahead and implemented
most of a marginally-preformant magnification solution for Linux.  We
are hoping to include some special new XServer stuff for getting global
expose/dirty-region notifications, etc. which will be important later
on, but we have an interim solution that's looking better than our
assessment of, say, 2-3 months ago.

There is however one important missing piece; fullscreen magnification
requires two X screens.  This is a problem for most people's Linux
setups, for obvious reasons which include limited support for multiple
video cards, etc.  Xvfb doesn't do the trick since it doesn't do
keyboard events, etc.

So what we need is a "virtual screen" DDX for the X server; presumably
using system memory.  Applications (e.g. the normal GNOME desktop) would
write to this virtual screen, to which the keyboard and mouse would be
connected, and the magnification service (which has a 'reference
implementation' in "gnome-mag") would grab pixels from the virtual
screen via normal X API and display the magnified result on the physical
X screen.

I am not sure what the current limits of the XFree86 server are with
respect to multiple screens; however even if two XServers were required,
this would still work (albeit possibly a little more slowly).  In fact
gnome-mag can be used in fullscreen mode now by specifying two X screens
which may not be on the same host.  Of course this is not terribly
performant, but the missing piece is just the "virtual screen" for
XFree86.

As I said there will be other features which we'll want, going forward,
but this is the only one that I know of that is a significant blocker
for Linux fullscreen magnification at this time. 

Thanks and best regards,

Bill

> 
> Rich
> 
> 
> Rich Schwerdtfeger
> Senior Technical Staff Member
> IBM Accessibility Center
> Research Division
> EMail/web: schwer us ibm com
> 
> "Two roads diverged in a wood, and I -
> I took the one less traveled by, and that has made all the difference.",
> Frost
> 
> 
> 
>                                                                                                                                         
>                       Bill Haneman                                                                                                      
>                       <bill haneman sun        To:       Richard Schwerdtfeger/Austin/IBM IBMUS                                         
>                       .com>                    cc:       Adi Dascal <ad baum ro>, gnome-accessibility-list gnome org, Michael Meeks     
>                                                 <michael ximian com>                                                                    
>                       08/22/2002 05:14         Subject:  Re: Gnopernicus                                                                
>                       AM                                                                                                                
>                                                                                                                                         
>                                                                                                                                         
> 
> 
> 
> Hi Rich:
> 
> I am glad that you are seeing some information from at-poke now and that
> you are making some headway.  Sorry that I haven't been more available
> to assist.
> 
> As you no doubt have observed, this stack is still a work-in-progress,
> though the infrastructure is substantially complete and API stable now
> (at least to a "1.0" state).  Gnopernicus and the applications' own
> accessibility support are necessarily lagging the infrastructure a
> little.
> 
> You might find 'gok' (the gnome onscreen keyboard) of interest, CVS
> module "gok"; despite some window manager interaction issues at present
> which limit its use in other than "Dwell Mode", it is a good demo of
> things to come with respect to support for mobility disorders.
> 
> The Gnopernicus magnification support is in its infancy, so I wouldn't
> be concerned if it does not work yet; the speech and braille output
> should be in a working (if not bug-free) state.
> 
> BTW, support for Java applications requires installation of the "Java
> Accessibility Bridge for GNOME" (cvs module java-bridge).
> 
> Best regards,
> 
> Bill
> 
> On Wed, 2002-08-21 at 21:34, Richard Schwerdtfeger wrote:
> >
> > I grabbed the latest Gnome update off of Ximian. atk-poke works although
> > some of the object data seems incomplete. Michael had asked about this
> > earlier.
> >
> > Now if I try and build gnopernicus I get aproblem where the build is
> > looking for gnome-mag-1.0. This is new. Where might it be?
> >
> > I cannot build. Am I missing a CVS package?
> >
> >
> > Rich Schwerdtfeger
> > Senior Technical Staff Member
> > IBM Accessibility Center
> > Research Division
> > EMail/web: schwer us ibm com
> >
> > "Two roads diverged in a wood, and I -
> > I took the one less traveled by, and that has made all the difference.",
> > Frost
> >
> >
> >
> >
> 
> >                       "Adi Dascal"
> 
> >                       <ad baum ro>             To:       "Michael Meeks"
> <michael ximian com>
> >                                                cc:       Richard
> Schwerdtfeger/Austin/IBM IBMUS, <gnome-accessibility-list gnome org>
> >                       08/22/2002 12:22         Subject:  Re: Gnopernicus
> 
> >                       PM
> 
> >
> 
> >
> 
> >
> >
> >
> > You are right Michael, only removing the directory it's not safe.(but
> > sometimes works, so this is the easy way, but not guaranted). A guaranted
> > way is described in the README file.(how to kill the daemon and so on).
> >
> > Adi.
> >
> > ----- Original Message -----
> > From: "Michael Meeks" <michael ximian com>
> > To: "Adi Dascal" <ad baum ro>
> > Cc: "Richard Schwerdtfeger" <schwer us ibm com>;
> > <gnome-accessibility-list gnome org>
> > Sent: Tuesday, August 20, 2002 4:18 PM
> > Subject: Re: Gnopernicus
> >
> >
> > >
> > > On Thu, 2002-08-22 at 16:30, Adi Dascal wrote:
> > > > building it, please erase the ~/.gconf/apps/gnopernicus directory.
> > >
> > > Ahh; I remember now - in addition to removing that directory, you badly
> > > need to kill gconfd first; there are 2 (~compatible) incarnations of
> > > gconfd -1 and -2, so:
> > >
> > > killall -9 gconfd-1 ; killall -9 gconfd-2
> > >
> > > [NB. pkill is better on Solaris ;-]
> > >
> > > Otherwise the daemon will cache state and return old key values I
> > > believe,
> > >
> > > Regards,
> > >
> > > Michael.
> > >
> > > --
> > >  mmeeks gnu org  <><, Pseudo Engineer, itinerant idiot
> > >
> >
> >
> >
> >
> >
> >
> > _______________________________________________
> > gnome-accessibility-list mailing list
> > gnome-accessibility-list gnome org
> > http://mail.gnome.org/mailman/listinfo/gnome-accessibility-list
> 
> 
> 
> 
> 
> 
>