+bool
+CanvasView::on_duck_angle_changed(const synfig::Angle &rotation,const synfigapp::ValueDesc& value_desc)
+{
+ // \todo will this really always be the case?
+ assert(value_desc.get_value_type() == ValueBase::TYPE_ANGLE);
+ return canvas_interface()->change_value(value_desc, value_desc.get_value(get_time()).get(Angle()) + rotation);
+}
+