@@ -678,8 +678,9 @@ class ZoomToAnimation(MoveToAnimation):

         rect = self.dot_widget.get_allocation()

         visible = min(rect.width, rect.height) / self.dot_widget.zoom_ratio

         visible *= 0.9

-        desired_middle_zoom = visible / distance

-        self.extra_zoom = min(0, 4 * (desired_middle_zoom - middle_zoom))

+        if distance > 0:

+            desired_middle_zoom = visible / distance

+            self.extra_zoom = min(0, 4 * (desired_middle_zoom - middle_zoom))

     def animate(self, t):

         a, b, c = self.source_zoom, self.extra_zoom, self.target_zoom