// PropXYXY.h

#ifndef PropXYXY_H
#define PropXYXY_H

// Propagates tracks from one XYPlane to another in a constant field.
//
// Propagation will fail if either the origin or destination is 
// not a XYPlane.
// Propagator works incorrectly for tracks with very small curvatures

#include "trfbase/PropDirected.h"
#include "trfbase/ObjDoublePtr.h"

namespace trf {

class PropXYXY : public PropDirected {

private:  // attributes

  ObjDoublePtr _bfield;

private:

  // output stream
  void ostr(std::ostream& stream) const;

public:  // static methods

  // Return the type name.
  static TypeName get_type_name() { return "PropXYXY"; }

  // Return the creator.
  static ObjCreator get_creator();

  // Return the type.
  static Type get_static_type() { return get_creator(); }

public:

  // constructor from magnetic field in Tesla.
  PropXYXY(ObjDoublePtr bfield);

  // destructor
  ~PropXYXY();

  // Clone.
  Propagator* new_propagator( ) const;

  // propagate a track without error in the specified direction
  PropStat vec_dir_prop( VTrack& trv, const Surface& srf,
			 PropDir dir,TrackDerivative* pder =0 ) const;

  // return the magnetic field
  double get_bfield() const;

  // Return the type.
  Type get_type() const { return get_static_type(); }

  // Write the object data.
  ObjData write_data() const;

};

}  // end namespace trf

#endif