text: /*=========================================================================
  
    Program:   Insight Segmentation & Registration Toolkit
    Module:    itkFEMElement2DC0QuadraticTriangular.h
    Language:  C++
    Date:      $Date$
    Version:   $Revision$
  
    Copyright (c) Insight Software Consortium. All rights reserved.
    See ITKCopyright.txt or http://www.itk.org/HTML/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 notices for more information.
  
  =========================================================================*/
  
  #ifndef __itkFEMElement2DC0QuadraticTriangular_h
  #define __itkFEMElement2DC0QuadraticTriangular_h
  
  #include "itkFEMElementStd.h"
  
  namespace itk {
  namespace fem {
  
  /**
   * \class Element2DC0QuadraticTriangular
   * \brief 3-noded, quadratic, C0 continuous finite element in 2D space.
   */
  class Element2DC0QuadraticTriangular : public ElementStd<6,2>
  {
    typedef ElementStd<3,2> TemplatedParentClass;
    FEM_ABSTRACT_CLASS( Element2DC0QuadraticTriangular, TemplatedParentClass )
  public:
  
    //////////////////////////////////////////////////////////////////////////
    /**
     * Methods related to numeric integration
     */
  
    enum { DefaultIntegrationOrder = 2 };
  
    virtual void GetIntegrationPointAndWeight(unsigned int i, VectorType& pt, Float& w, unsigned int order) const;
  
    virtual unsigned int GetNumberOfIntegrationPoints(unsigned int order) const;
  
    //////////////////////////////////////////////////////////////////////////
    /**
     * Methods related to the geometry of an element
     */
  
    virtual VectorType ShapeFunctions( const VectorType& pt ) const;
  
    virtual void ShapeFunctionDerivatives( const VectorType& pt, MatrixType& shapeD ) const;
  
    // FIXME: Write a proper implementation
    virtual bool GetLocalFromGlobalCoordinates( const VectorType&, VectorType& ) const
      { 
      throw;
      return false;
      }
  
    // Since the Jacobian is not quadratic, we need to provide our
    // own implementation of calculating the determinant and inverse.
    virtual Float JacobianDeterminant( const VectorType& pt, const MatrixType* pJ = 0 ) const;
    virtual void JacobianInverse( const VectorType& pt, MatrixType& invJ, const MatrixType* pJ = 0 ) const;
  
    /**
     * Draw the element on the specified device context
     */
  #ifdef FEM_BUILD_VISUALIZATION
    void Draw(CDC* pDC, Solution::ConstPointer sol) const;
  #endif
  
  };
  
  }} // end namespace itk::fem
  
  #endif  // #ifndef __itkFEMElement2DC0QuadraticTriangular_h
  