double _drag_distance; ///< total x movement of the drag, in units
double _last_drag_fraction; ///< last y position of the drag, as a fraction
std::list<double> _always_in_view;
double _drag_distance; ///< total x movement of the drag, in units
double _last_drag_fraction; ///< last y position of the drag, as a fraction
std::list<double> _always_in_view;