[virt-tools-list] [PATCH virt-viewer] Don't resize guest display on zoom change

[Marc-André Lureau]

ack

----- Original Message -----
> still need review on this.  haven't noticed any regressions in the past week.
> 
> 
> ----- Original Message -----
> > From: "Jonathon Jongsma" <jjongsma at redhat.com>
> > To: virt-tools-list at redhat.com
> > Sent: Thursday, March 6, 2014 4:15:25 PM
> > Subject: [virt-tools-list] [PATCH virt-viewer] Don't resize guest display
> > on	zoom change
> > 
> > When the zoom level is changed, the virt-viewer window gets resized. But we
> > don't want this to trigger a resize of the guest display. But occasionally
> > rounding errors cause the guest display to be reconfigured when zooming
> > out.
> > To
> > fix this, we first check whether the current size is the preferred size.
> > If
> > it
> > is, we don't send down a resize command to the guest.
> > 
> > In addition to preventing guest resizes in response to zooming, it also
> > improves
> > the behavior when the guest display resolution is changed from within the
> > guest.
> > Before this change, we'd have the following behavior:
> >     A. guest changes display to WxH
> >     B. client gets notified of change and resizes the window to WxH
> >     C. client responds to window resize by sending a new monitor config
> >     command to the guest
> > 
> > With this change, the extra step C will be avoided because we're already at
> > the
> > preferred size.
> > 
> > Resolves: rhbz#1004051
> > ---
> > 
> > Here's a more complete patch that doesn't cause the regression I mentioned
> > in
> > the last email.
> > 
> > A quick description of the regression: when more tha one display was
> > enabled,
> > the displays would initially show up at the right size and then be resized
> > down
> > to very small (<400x400) size.
> > 
> > Quick summary of the cause of the regression: windows are created with a
> > default
> > size of 400x400.  When the display is initially added to the window and
> > shown,
> > it will cause an initial allocation of slightly less than 400x400, followed
> > by a
> > resize to the actual the size of display. It's a bit surprising that this
> > ever
> > worked properly, but my previous patch was enough to violate some
> > assumptions,
> > causing it to break.
> > 
> > The solution is to ignore all allocations that happen before the widget is
> > mapped to screen. We really don't want to be sending guest resize commands
> > due
> > to allocations that aren't due to explicit user actions.
> > 
> > 
> >  src/virt-viewer-display-spice.c | 21 ++++++++++++++++++++-
> >  1 file changed, 20 insertions(+), 1 deletion(-)
> > 
> > diff --git a/src/virt-viewer-display-spice.c
> > b/src/virt-viewer-display-spice.c
> > index d13fbda..a803ab0 100644
> > --- a/src/virt-viewer-display-spice.c
> > +++ b/src/virt-viewer-display-spice.c
> > @@ -190,9 +190,28 @@ virt_viewer_display_spice_mouse_grab(SpiceDisplay
> > *display G_GNUC_UNUSED,
> >  
> >  static void
> >  virt_viewer_display_spice_size_allocate(VirtViewerDisplaySpice *self,
> > -                                        GtkAllocation *allocation
> > G_GNUC_UNUSED,
> > +                                        GtkAllocation *allocation,
> >                                          gpointer data G_GNUC_UNUSED)
> >  {
> > +    GtkRequisition preferred;
> > +
> > +    /* ignore all allocations before the widget gets mapped to screen
> > since
> > we
> > +     * only want to trigger guest resizing due to user actions
> > +     */
> > +    if (!gtk_widget_get_mapped(GTK_WIDGET(self)))
> > +        return;
> > +
> > +    /* when the window gets resized due to a change in zoom level, we
> > don't
> > want
> > +     * to re-size the guest display.  So if we get an allocation event
> > that
> > +     * resizes the window to the size it already wants to be (based on
> > desktop
> > +     * size and zoom level), just return early
> > +     */
> > +    gtk_widget_get_preferred_size(GTK_WIDGET(self), NULL, &preferred);
> > +    if (preferred.width == allocation->width
> > +        && preferred.height == allocation->height) {
> > +        return;
> > +    }
> > +
> >      if (self->priv->auto_resize != AUTO_RESIZE_NEVER)
> >          virt_viewer_display_spice_monitor_geometry_changed(self);
> >  
> > --
> > 1.8.5.3
> > 
> > _______________________________________________
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> > virt-tools-list at redhat.com
> > https://www.redhat.com/mailman/listinfo/virt-tools-list
> > 
> 
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