// SpaceXform.h

#ifndef SpaceXform_H
#define SpaceXform_H

// Abstract interface for a class that transforms a SpacePoint
// or SpacePointVector.
//
// Transformation may be invoked with xf.apply(spt) or xf(spt).
// Inverse may be applied with xf.inverse()(spt) or xf.invert(spt).
// In all cases the original value is unchanged and the transformed
// value is returned.

#include "spacegeom/SpacePoint.h"
#include "spacegeom/SpacePointVector.h"

class SpaceXform {

public:  // methods to be implemented in subclass

  // Return the inverse of this transformation.
  // The subclass manages its inverse--the inverse transformation
  // should be destroyed when and only when the original is destroyed.
  virtual const SpaceXform& inverse() const =0;

  // Transform a space point.
  virtual SpacePoint apply(const SpacePoint& spt) const =0;

  // Transform a space point vector.
  virtual SpacePointVector apply(const SpacePointVector& svec) const =0;

public:  // methods implemented here

  // destructor
  virtual ~SpaceXform();

  // Transform a space point.
  SpacePoint operator()(const SpacePoint& spt) const {
    return apply(spt);
  }

  // Transform a space point vector.
  SpacePointVector operator()(const SpacePointVector& svec) const {
    return apply(svec);
  }

  // Transform a space point with inverse transformation.
  SpacePoint invert(const SpacePoint& spt) const {
    return inverse().apply(spt);
  }

  // Transform a space point vector with inverse transformation.
  SpacePoint invert(const SpacePointVector& svec) const {
    return inverse().apply(svec);
  }

};

#endif