/*=========================================================================

  Program:   Visualization Toolkit
  Module:    $RCSfile: vtkWarpTransform.h,v $

  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
  All rights reserved.
  See Copyright.txt or http://www.kitware.com/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notice for more information.

=========================================================================*/
// .NAME vtkWarpTransform - superclass for nonlinear geometric transformations
// .SECTION Description
// vtkWarpTransform provides a generic interface for nonlinear 
// warp transformations.
// .SECTION see also
// vtkThinPlateSplineTransform vtkGridTransform vtkGeneralTransform


#ifndef __vtkWarpTransform_h
#define __vtkWarpTransform_h

#include "vtkAbstractTransform.h"

class VTK_COMMON_EXPORT vtkWarpTransform : public vtkAbstractTransform
{
public:

  vtkTypeRevisionMacro(vtkWarpTransform,vtkAbstractTransform);
  void PrintSelf(ostream& os, vtkIndent indent);

  // Description:
  // Invert the transformation.  Warp transformations are usually
  // inverted using an iterative technique such as Newton's method.
  // The inverse transform is usually around five or six times as
  // computationally expensive as the forward transform.
  void Inverse();

  // Description:
  // Get the inverse flag of the transformation.  This flag is
  // set to zero when the transformation is first created, and
  // is flipped each time Inverse() is called.
  vtkGetMacro(InverseFlag,int);

  // Description:
  // Set the tolerance for inverse transformation.
  // The default is 0.001.
  vtkSetMacro(InverseTolerance,double);
  vtkGetMacro(InverseTolerance,double);

  // Description:
  // Set the maximum number of iterations for the inverse
  // transformation.  The default is 500, but usually only 
  // 2 to 5 iterations are used.  The inversion method
  // is fairly robust, and it should converge for nearly all smooth
  // transformations that do not fold back on themselves.
  vtkSetMacro(InverseIterations,int);
  vtkGetMacro(InverseIterations,int);

  // Description:
  // This will calculate the transformation without calling Update.
  // Meant for use only within other VTK classes.
  void InternalTransformPoint(const float in[3], float out[3]);
  void InternalTransformPoint(const double in[3], double out[3]);

  // Description:
  // This will calculate the transformation, as well as its derivative
  // without calling Update.  Meant for use only within other VTK
  // classes.
  void InternalTransformDerivative(const float in[3], float out[3],
                                   float derivative[3][3]);
  void InternalTransformDerivative(const double in[3], double out[3],
                                   double derivative[3][3]);

  // Description:
  // Do not use these methods.  They exists only as a work-around for
  // internal templated functions (I really didn't want to make the
  // Forward/Inverse methods public, is there a decent work around
  // for this sort of thing?)
  void TemplateTransformPoint(const float in[3], float out[3]) {
    this->ForwardTransformPoint(in,out); }; 
  void TemplateTransformPoint(const double in[3], double out[3]) {
    this->ForwardTransformPoint(in,out); }; 
  void TemplateTransformPoint(const float in[3], float out[3],
                              float derivative[3][3]) {
    this->ForwardTransformDerivative(in,out,derivative); }; 
  void TemplateTransformPoint(const double in[3], double out[3],
                              double derivative[3][3]) {
    this->ForwardTransformDerivative(in,out,derivative); }; 
  void TemplateTransformInverse(const float in[3], float out[3]) {
    this->InverseTransformPoint(in,out); }; 
  void TemplateTransformInverse(const double in[3], double out[3]) {
    this->InverseTransformPoint(in,out); }; 
  void TemplateTransformInverse(const float in[3], float out[3],
                                float derivative[3][3]) {
    this->InverseTransformDerivative(in,out,derivative); }; 
  void TemplateTransformInverse(const double in[3], double out[3],
                                double derivative[3][3]) {
    this->InverseTransformDerivative(in,out,derivative); }; 

protected:
  vtkWarpTransform();
  ~vtkWarpTransform();

  // Description:
  // If the InverseFlag is set to 0, then a call to InternalTransformPoint
  // results in a call to ForwardTransformPoint. 
  virtual void ForwardTransformPoint(const float in[3], float out[3]) = 0;
  virtual void ForwardTransformPoint(const double in[3], double out[3]) = 0;

  // Description:
  // Calculate the forward transform as well as the derivative. 
  virtual void ForwardTransformDerivative(const float in[3], float out[3],
                                          float derivative[3][3]) = 0;
  virtual void ForwardTransformDerivative(const double in[3], double out[3],
                                          double derivative[3][3]) = 0;

  // Description:
  // If the InverseFlag is set to 1, then a call to InternalTransformPoint
  // results in a call to InverseTransformPoint.  The inverse transformation
  // is calculated from using Newton's method.
  virtual void InverseTransformPoint(const float in[3], float out[3]);
  virtual void InverseTransformPoint(const double in[3], double out[3]);

  // Description:
  // Calculate the inverse transform as well as the derivative of the
  // forward transform (that's correct: the derivative of the
  // forward transform, not of the inverse transform)
  virtual void InverseTransformDerivative(const float in[3], float out[3],
                                          float derivative[3][3]);
  virtual void InverseTransformDerivative(const double in[3], double out[3],
                                          double derivative[3][3]);

  int InverseFlag;
  int InverseIterations;
  double InverseTolerance;
private:
  vtkWarpTransform(const vtkWarpTransform&);  // Not implemented.
  void operator=(const vtkWarpTransform&);  // Not implemented.
};

#endif