vtkTransform2D.h

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

  Program:   Visualization Toolkit
  Module:    vtkTransform2D.h

  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 vtkTransform2D - describes linear transformations via a 3x3 matrix
// .SECTION Description
// A vtkTransform2D can be used to describe the full range of linear (also
// known as affine) coordinate transformations in two dimensions,
// which are internally represented as a 3x3 homogeneous transformation
// matrix.  When you create a new vtkTransform2D, it is always initialized
// to the identity transformation.
//
// This class performs all of its operations in a right handed
// coordinate system with right handed rotations. Some other graphics
// libraries use left handed coordinate systems and rotations.

#ifndef __vtkTransform2D_h
#define __vtkTransform2D_h

#include "vtkObject.h"

#include "vtkMatrix3x3.h" // Needed for inline methods

class vtkPoints2D;

class VTK_COMMON_EXPORT vtkTransform2D : public vtkObject
{
 public:
  static vtkTransform2D *New();
  vtkTypeMacro(vtkTransform2D,vtkObject);
  void PrintSelf(ostream& os, vtkIndent indent);

  // Description:
  // Set the transformation to the identity transformation.
  void Identity();

  // Description:
  // Invert the transformation.
  void Inverse();

  // Description:
  // Create a translation matrix and concatenate it with the current
  // transformation.
  void Translate(double x, double y);
  void Translate(const double x[2]) { this->Translate(x[0], x[1]); }
  void Translate(const float x[2]) { this->Translate(x[0], x[1]); }

  // Description:
  // Create a rotation matrix and concatenate it with the current
  // transformation. The angle is in degrees.
  void Rotate(double angle);

  // Description:
  // Create a scale matrix (i.e. set the diagonal elements to x, y)
  // and concatenate it with the current transformation.
  void Scale(double x, double y);
  void Scale(const double s[2]) { this->Scale(s[0], s[1]); }
  void Scale(const float s[2]) { this->Scale(s[0], s[1]); }

  // Description:
  // Set the current matrix directly.
  void SetMatrix(vtkMatrix3x3 *matrix) {
    this->SetMatrix(matrix->GetData()); }
  void SetMatrix(const double elements[9]);

  // Description:
  // Get the underlying 3x3 matrix.
  vtkGetObjectMacro(Matrix, vtkMatrix3x3);
  void GetMatrix(vtkMatrix3x3 *matrix);

  // Description:
  // Return the position from the current transformation matrix as an array
  // of two floating point numbers. This is simply returning the translation
  // component of the 3x3 matrix.
  void GetPosition(double pos[2]);
  void GetPosition(float pos[2]) {
    double temp[2];
    this->GetPosition(temp);
    pos[0] = static_cast<float>(temp[0]);
    pos[1] = static_cast<float>(temp[1]); }

  // Description:
  // Return a matrix which is the inverse of the current transformation
  // matrix.
  void GetInverse(vtkMatrix3x3 *inverse);

  // Description:
  // Return a matrix which is the transpose of the current transformation
  // matrix.  This is equivalent to the inverse if and only if the
  // transformation is a pure rotation with no translation or scale.
  void GetTranspose(vtkMatrix3x3 *transpose);

  // Description:
  // Override GetMTime to account for input and concatenation.
  unsigned long GetMTime();

  // Description:
  // Apply the transformation to a series of points, and append the
  // results to outPts. Where n is the number of points, and the float pointers
  // are of length 2*n.
  void TransformPoints(const float *inPts, float *outPts, int n);

  // Description:
  // Apply the transformation to a series of points, and append the
  // results to outPts. Where n is the number of points, and the float pointers
  // are of length 2*n.
  void TransformPoints(const double *inPts, double *outPts, int n);

  // Description:
  // Apply the transformation to a series of points, and append the
  // results to outPts.
  void TransformPoints(vtkPoints2D *inPts, vtkPoints2D *outPts);

  // Description:
  // Apply the transformation to a series of points, and append the
  // results to outPts. Where n is the number of points, and the float pointers
  // are of length 2*n.
  void InverseTransformPoints(const float *inPts, float *outPts, int n);

  // Description:
  // Apply the transformation to a series of points, and append the
  // results to outPts. Where n is the number of points, and the float pointers
  // are of length 2*n.
  void InverseTransformPoints(const double *inPts, double *outPts, int n);

  // Description:
  // Apply the transformation to a series of points, and append the
  // results to outPts.
  void InverseTransformPoints(vtkPoints2D *inPts, vtkPoints2D *outPts);

  // Description:
  // Use this method only if you wish to compute the transformation in
  // homogeneous (x,y,w) coordinates, otherwise use TransformPoint().
  // This method calls this->GetMatrix()->MultiplyPoint().
  void MultiplyPoint(const float in[3], float out[3]) {
    this->GetMatrix()->MultiplyPoint(in,out);};
  void MultiplyPoint(const double in[3], double out[3]) {
    this->GetMatrix()->MultiplyPoint(in,out);};

protected:
  vtkTransform2D ();
  ~vtkTransform2D ();

  void InternalDeepCopy(vtkTransform2D *t);

  vtkMatrix3x3 *Matrix;
  vtkMatrix3x3 *InverseMatrix;

private:
  vtkTransform2D (const vtkTransform2D&);  // Not implemented
  void operator=(const vtkTransform2D&);  // Not implemented
};

#endif