Re: [g-a-devel] [discovered] any idea what could be causing the bug #171465 in gnome-mag

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

Hi Bill,

I discovered what is causing the error. The zoom_region->priv->pixmap 
and zoom_region->priv->scaled_pixbuf is not setted correctly when we 
have vertical split mode with the magnified area left part of the screen 
or horizontal split mode with the magnified area in the top of the screen.

I will try to develop an patch for it in this weekend. I will be busy 
today to do it, but if you want to test it and find easy to fix it do 
the following to make the error disappear:

alter the function zoom_region_create_pixmap to:

long width = 1024 * zoom_region->xscale;
long height = 768 * zoom_region->xscale;

and add the following to the function zoom_region_set_viewport after the 
dispose and allocation of zoom_region->priv->pixmap the following:

if (zoom_region->priv->scaled_pixbuf)
               g_object_unref (zoom_region->priv->scaled_pixbuf);
zoom_region->priv->scaled_pixbuf =
         gdk_pixbuf_new (GDK_COLORSPACE_RGB, FALSE, 8,
                 1024 * zoom_region->xscale + 1,
                 768 * zoom_region->yscale + 1);

Like you see I test it in 1024x768.

Now you can do what Dragan Sarbut described in the first post in 
bugzilla and now the magnification works.

By the way, I think that the space allocated, in the original code, to 
pixmap and scaled_pixbuf are too big, this is made this way to cache 
magnified areas?

Best regards,
Carlos.

Bill Haneman wrote:

> Hi Carlos:
>
> The problem with values being reset by gnopernicus is a gnopernicus 
> bug.  I do not know whether it is fixed in CVS HEAD or not.
>
> Once you set your system up for horizontal magnification, it is 
> expected to work correctly after restarting gnopernicus.   You should 
> only need to do this once, unless you are frequently changing your 
> magnified region bounds.  It also seems to me that for many reasons 
> you might get better results using fullscreen magnification instead; 
> this is documented in the Gnome Accessibility Guide for gnome 2.10.
>
> I cannot reproduce the problem you are seeing with horizontal 
> magnification on my system.
>
> Bill
>
> Carlos Eduardo Rodrigues Diogenes wrote:
>
> > Bill Haneman wrote:
> >
> > > Carlos
> > >
> > > Sorry, I think restarting gnopernicus is a perfectly reasonable 
> > > thing to do in this case.
> >
> >
> >
> > If it's work it's a solution, but in the user standpoint have to do 
> > this type of thing is not very confortable.
> >
> > > I do not see the bug on my system using gnopernicus.  Are you using 
> > > gnome-mag in standalone mode, is that what you are saying?
> >
> >
> >
> > I do it using gnopernicus. To be more precisely I'm using the 
> > 1024x768 resolution and put the following values in gnopernicus:
> >
> > Left: 359
> > Top: 0
> > Right: 1022
> > Bottom: 450
> >
> > Applyed and the magnified screen stay gray. I restarted gnopernicus 
> > and it still stay gray.
> >
> > I put too the following values to take an horizontal split mode:
> >
> > Left: 0
> > Top: 0
> > Right: 1022
> > Bottom: 350
> >
> > And the magnified screen stay gray too. Only a really small part of 
> > the user screen is magnified, this part is immediately below the 
> > magnified area.
> >
> > Other thing that I noticed is that if the Rigth option is set to 1023 
> > when gnopernicus is restarted the Left option is setted to 511.
> >
> > Carlos.
> >
> > > The steps in the control-client test you give is not something an 
> > > end-user would normally need to do.  I would recommend starting the 
> > > magnifier with 'magnifier -mh' if you want horizontal magnification.
> > >
> > > Bill
> > >
> > > > By the way... restart gnopernicus is not the right way to resolve 
> > > > the things, but I can't make the magnifier show the right image in 
> > > > any way and you say me that it's working in your system, so I can't 
> > > > go to anywhere. Do you have any idea what I could do?
> > > >
> > > > Maybe this way the question become more clear: In gnome-mag code, 
> > > > what could be causing this stranger behavior? Because I analyze the 
> > > > code and it appear ok, but It does not work properly.
> > > >
> > > > If you run in your prompt:
> > > >
> > > > #: magnifier -mv
> > > > #: ./control-client T
> > > > #: ./control-client b
> > > >
> > > > You stay with I gray magnifier screen, do you know why or where to 
> > > > start investigating to resolve this?
> > > >
> > > > > Bill
> >
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