Re: [g-a-devel] Questions about the gnome-mag design

[Carlos Eduardo Rodrigues Diogenes <cerdiogenes yahoo com br>]

Bill Haneman wrote:

> Carlos
>
> Try specifying the screen number in your call, for instance:
>
> magnifier -mv -t myip:0.0 -s myip:0.0

Yes, this work, but the delay to show the magnified area is worst then I 
executing the application in my machine. I think that the X traffic is 
too high.

> However I have never tested the magnifier with source and target the 
> same, but both remote.
> You might also try
>
> magnifier -display myip:0.0 -mv
>
> or setting the DISPLAY env variable before starting the magnifier.  
> One of those should work I think.
>
> Bill
>
> Carlos Eduardo Rodrigues Diogenes wrote:
>
> > Bill Haneman wrote:
> >
> > > (sorry for replying to myself - this is a clarification)
> > > Bill Haneman wrote:...
> > >
> > > > Also, there are situations where the magnifier service may need to 
> > > > run on a different host from the client.  For instance, if you are 
> > > > running a remote application, you don't really want the magnifier 
> > > > to run remotely as well, because of the much larger amount of X 
> > > > traffic and the CPU requirements of the magnification service.  
> > > > CORBA allows this at least in theory (although our current 
> > > > 'bonobo-activation' mechanism does not recognize remote servers).
> > The CPU requirements isn't is a big problem, because if you start the
> > gnome-mag in a remote machine, probably, this machine will have a better
> > CPU than the machine that is running the X Server. The X traffic is
> > really important, but I think that it's not a big problem, because we
> > have solutions like vino and xdmcp that works really fine, and how
> > gnome-mag uses the DAMAGE extension this problem is minimized. I raised
> > this aspect, because here in Brazil we have many places with old
> > machines, that will not support a good magnifier without delay, so is
> > more cheap buy a good server and use the old machines like dummy 
> > terminals.
> >
> > > By this I mean that "bonobo-activation-server" doesn't report remote 
> > > magnification services to a client which is requesting an instance 
> > > of gnome-mag.  However, gnome-mag should work fine with remote _X 
> > > servers_ as far as I know - at least, I have used this feature in 
> > > the past.  (Carlos, did you get this working on your system? Maybe a 
> > > bug somewhere?)
> >
> >
> >
> > no... here is the output of what I get when I call gnome-mag with this
> > command line in the remote machine:
> >
> > #: magnifier -mv -t myip:0 -s myip:0
> >
> > (magnifier:19579): Bonobo-WARNING **: Assigning a default value to a non
> > readable property 'source-display-screen'
> >
> > (magnifier:19579): Bonobo-WARNING **: Assigning a default value to a non
> > readable property 'target-display-screen'
> >
> > (magnifier:19579): Gdk-CRITICAL **: gdk_display_get_screen: assertion
> > `ScreenCount (GDK_DISPLAY_X11 (display)->xdisplay) > screen_num' failed
> >
> > (magnifier:19579): Gdk-CRITICAL **: gdk_screen_get_root_window:
> > assertion `GDK_IS_SCREEN (screen)' failed
> >
> > (magnifier:19579): Gdk-CRITICAL **: gdk_display_get_screen: assertion
> > `ScreenCount (GDK_DISPLAY_X11 (display)->xdisplay) > screen_num' failed
> >
> > (magnifier:19579): Gdk-CRITICAL **: gdk_screen_get_root_window:
> > assertion `GDK_IS_SCREEN (screen)' failed
> >
> > (magnifier:19579): Gdk-CRITICAL **: gdk_display_get_screen: assertion
> > `ScreenCount (GDK_DISPLAY_X11 (display)->xdisplay) > screen_num' failed
> >
> > (magnifier:19579): Gdk-CRITICAL **: gdk_screen_get_width: assertion
> > `GDK_IS_SCREEN (screen)' failed
> >
> > (magnifier:19579): Gdk-CRITICAL **: gdk_display_get_screen: assertion
> > `ScreenCount (GDK_DISPLAY_X11 (display)->xdisplay) > screen_num' failed
> >
> > (magnifier:19579): Gdk-CRITICAL **: gdk_screen_get_height: assertion
> > `GDK_IS_SCREEN (screen)' failed
> >
> > (magnifier:19579): Gdk-CRITICAL **: gdk_display_get_screen: assertion
> > `ScreenCount (GDK_DISPLAY_X11 (display)->xdisplay) > screen_num' failed
> >
> > (magnifier:19579): Gdk-CRITICAL **: gdk_screen_get_width: assertion
> > `GDK_IS_SCREEN (screen)' failed
> >
> > (magnifier:19579): Gdk-CRITICAL **: gdk_display_get_screen: assertion
> > `ScreenCount (GDK_DISPLAY_X11 (display)->xdisplay) > screen_num' failed
> >
> > (magnifier:19579): Gdk-CRITICAL **: gdk_screen_get_height: assertion
> > `GDK_IS_SCREEN (screen)' failed
> >
> > (magnifier:19579): Gdk-CRITICAL **: gdk_display_get_screen: assertion
> > `ScreenCount (GDK_DISPLAY_X11 (display)->xdisplay) > screen_num' failed
> >
> > (magnifier:19579): Gdk-CRITICAL **: gdk_screen_get_root_window:
> > assertion `GDK_IS_SCREEN (screen)' failed
> >
> > (magnifier:19579): Gdk-CRITICAL **: gdk_display_get_screen: assertion
> > `ScreenCount (GDK_DISPLAY_X11 (display)->xdisplay) > screen_num' failed
> >
> > (magnifier:19579): Gdk-CRITICAL **: gdk_screen_get_root_window:
> > assertion `GDK_IS_SCREEN (screen)' failed
> >
> > (magnifier:19579): Gdk-WARNING **: gdkdrawable-x11.c:904 drawable is not
> > a pixmap or window
> > The program 'magnifier' received an X Window System error.
> > This probably reflects a bug in the program.
> > The error was 'BadDrawable (invalid Pixmap or Window parameter)'.
> >   (Details: serial 9 error_code 9 request_code 154 minor_code 1)
> >   (Note to programmers: normally, X errors are reported asynchronously;
> >    that is, you will receive the error a while after causing it.
> >    To debug your program, run it with the --sync command line
> >    option to change this behavior. You can then get a meaningful
> >    backtrace from your debugger if you break on the gdk_x_error() 
> > function.)
> >
> > > If we can get the bonobo-activation-server to return the CORBA 
> > > object ID of a remote gnome-mag service (or hack some other 
> > > mechanism for getting the object ID), then a remote client (for 
> > > instance, a remote instance of gnopernicus) can talk to a local 
> > > gnome-mag service through the bonobo/CORBA IPC interface.
> > >
> > > Bill
> > >
> > > > This sort of case is probably more common in some corporate 
> > > > environments, but we are not sure just how important it will be in 
> > > > the future.