+void Widget::set_animation_interval(const Time::TimeDelta &iv)
+{
+ if(iv<Time::zero)
+ throw invalid_argument("Widget::set_animation_interval");
+
+ anim_interval = iv;
+ signal_request_animation.emit(anim_interval);
+}
+
+void Widget::stop_animation()
+{
+ set_animation_interval(Time::zero);
+}
+