[libdazzle] animation: expand invalidation area for next invalidate

[Christian Hergert <chergert src gnome org>]

commit a6b1628f21210ef1a1c2d7fb3c6f7df21de56264
Author: Christian Hergert <chergert redhat com>
Date:   Sat Jun 24 15:11:16 2017 -0700

    animation: expand invalidation area for next invalidate
    
    We sometimes get a straggler line at the edge of a movement.
    Increasing this by 1 seems to work. My current guess is that
    the bounding box is not inclusive of the final pixel.

 src/animation/dzl-box-theatric.c |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)
---
diff --git a/src/animation/dzl-box-theatric.c b/src/animation/dzl-box-theatric.c
index 09b5375..8163453 100644
--- a/src/animation/dzl-box-theatric.c
+++ b/src/animation/dzl-box-theatric.c
@@ -154,6 +154,14 @@ on_toplevel_draw (GtkWidget      *widget,
 
   self->last_area = area;
 
+  /* The invalidation rectangle does not appear to be inclusive.
+   * This means that occcasionly we seem to have a stragler line.
+   * But setting this to one seems to make that go away for the
+   * current tests I have.
+   */
+  self->last_area.width += 1;
+  self->last_area.height += 1;
+
   return FALSE;
 }