[PATCH] xwayland: Use frame geometry for resizing shell surface

[Pekka Paalanen]

On Mon, 25 Aug 2014 10:17:48 +0200
"Nils Chr. Brause" <nilschrbrause at gmail.com> wrote:

> I also noticed this in current master. This seems to fix the problem. :)
> 
> Reviewed-by: Nils Chr. Brause <nilschrbrause at gmail.com>
> 
> 
> 
> On Thu, Aug 21, 2014 at 2:51 AM, Ondřej Majerech <majerech.o at gmail.com>
> wrote:
> 
> > We want to set the size of the entire window, not just the input area.
> > This fixes the bug where resizing an X client under XWayland would make
> > the window snap to a smaller size, and the pointer would then stay a
> > distance away from the frame.
> >
> > Signed-off-by: Ondřej Majerech <majerech.o at gmail.com>
> > ---
> >  xwayland/window-manager.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/xwayland/window-manager.c b/xwayland/window-manager.c
> > index f1523f5..36df855 100644
> > --- a/xwayland/window-manager.c
> > +++ b/xwayland/window-manager.c
> > @@ -1009,7 +1009,7 @@ weston_wm_window_draw_decoration(void *data)
> >                                           input_x, input_y, input_w,
> > input_h);
> >
> >                 shell_interface->set_window_geometry(window->shsurf,
> > -                                                    input_x, input_y,
> > input_w, input_h);
> > +                                                    x, y, width, height);
> >         }
> >  }

Hi,

this patch does indeed fix the problem, but I do not understand why.

There is just one wl_surface, I assume. There is the shadow region of
the decorations. I would think that the input region is the surface
region without the shadow region. Why is the input region different
from the window geometry, should those not be the same values here?

The function starts with:

	weston_wm_window_get_frame_size(window, &width, &height);
	weston_wm_window_get_child_position(window, &x, &y);

So width,height becomes the frame width,height, which does not include
shadows, I believe. That seems ok.

x,y become the top-left corner of the window content in wl_surface
coordinates? But that's not the right geometry, you should be including
the decorations too? Or if not decorations, then isn't widht,height
wrong because those include decorations?

Now, input_{x,y,w,h} are the frame's input rect, including also the
actual window content with the decorations. Why does using those go so
far off?

This is a screenshot of the problem:
http://people.collabora.com/~pq/xwayland-resize-cursor-geometry-bug.png

As you can see, the cursor is roughly twice as much off the corner as
is the shadow width.

I think there might be something else broken, and this just hides the
real bug. Can you explain?


Thanks,
pq