Interaction/Widgets/vtkContourRepresentation.cxx

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

  Program:   Visualization Toolkit
  Module:    vtkContourRepresentation.cxx

  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.

=========================================================================*/
#include "vtkContourRepresentation.h"

#include "vtkBox.h"
#include "vtkCamera.h"
#include "vtkCellArray.h"
#include "vtkContourLineInterpolator.h"
#include "vtkCoordinate.h"
#include "vtkHandleRepresentation.h"
#include "vtkIncrementalOctreePointLocator.h"
#include "vtkIntArray.h"
#include "vtkInteractorObserver.h"
#include "vtkLine.h"
#include "vtkMath.h"
#include "vtkMatrix4x4.h"
#include "vtkObjectFactory.h"
#include "vtkPointPlacer.h"
#include "vtkPolyData.h"
#include "vtkRenderer.h"
#include "vtkWindow.h"

#include <set>
#include <algorithm>
#include <iterator>

vtkCxxSetObjectMacro(vtkContourRepresentation, PointPlacer, vtkPointPlacer);
vtkCxxSetObjectMacro(vtkContourRepresentation, LineInterpolator, vtkContourLineInterpolator);

//----------------------------------------------------------------------
vtkContourRepresentation::vtkContourRepresentation()
{
  this->Internal = new vtkContourRepresentationInternals;

  this->PixelTolerance           = 7;
  this->WorldTolerance           = 0.001;
  this->PointPlacer              = nullptr;
  this->LineInterpolator         = nullptr;
  this->Locator                  = nullptr;
  this->RebuildLocator           = false;
  this->ActiveNode               = -1;
  this->NeedToRender             = 0;
  this->ClosedLoop               = 0;
  this->ShowSelectedNodes        = 0;
  this->CurrentOperation         = vtkContourRepresentation::Inactive;

  this->ResetLocator();
}

//----------------------------------------------------------------------
vtkContourRepresentation::~vtkContourRepresentation()
{
  this->SetPointPlacer(nullptr);
  this->SetLineInterpolator(nullptr);
  this->Internal->ClearNodes();

  delete this->Internal;

  if (this->Locator)
  {
    this->Locator->Delete();
  }
}

//----------------------------------------------------------------------
void vtkContourRepresentation::ResetLocator()
{
  if (this->Locator)
  {
    this->Locator->Delete();
  }

  this->Locator = vtkIncrementalOctreePointLocator::New();
  this->Locator->SetBuildCubicOctree(1);
  this->RebuildLocator = true;
}

//----------------------------------------------------------------------
void vtkContourRepresentation::ClearAllNodes()
{
  this->ResetLocator();
  this->Internal->ClearNodes();

  this->BuildLines();
  this->BuildLocator();
  this->NeedToRender = 1;
  this->Modified();
}

//----------------------------------------------------------------------
void vtkContourRepresentation::AddNodeAtPositionInternal( double worldPos[3],
                                                          double worldOrient[9],
                                                          double displayPos[2] )
{
  // Add a new point at this position
  vtkContourRepresentationNode *node = new vtkContourRepresentationNode;
  node->WorldPosition[0] = worldPos[0];
  node->WorldPosition[1] = worldPos[1];
  node->WorldPosition[2] = worldPos[2];
  node->Selected = 0;

  node->NormalizedDisplayPosition[0] = displayPos[0];
  node->NormalizedDisplayPosition[1] = displayPos[1];
  this->Renderer->DisplayToNormalizedDisplay(
      node->NormalizedDisplayPosition[0],
      node->NormalizedDisplayPosition[1] );

  memcpy(node->WorldOrientation, worldOrient, 9*sizeof(double) );

  this->Internal->Nodes.push_back(node);

  if ( this->LineInterpolator && this->GetNumberOfNodes() > 1 )
  {
    // Give the line interpolator a chance to update the node.
    int didNodeChange = this->LineInterpolator->UpdateNode(
        this->Renderer, this, node->WorldPosition, this->GetNumberOfNodes()-1 );

    // Give the point placer a chance to validate the updated node. If its not
    // valid, discard the LineInterpolator's change.
    if ( didNodeChange && !this->PointPlacer->ValidateWorldPosition(
                node->WorldPosition, worldOrient ) )
    {
      node->WorldPosition[0] = worldPos[0];
      node->WorldPosition[1] = worldPos[1];
      node->WorldPosition[2] = worldPos[2];
    }
  }

  this->UpdateLines( static_cast<int>(this->Internal->Nodes.size())-1);
  this->NeedToRender = 1;
}

//----------------------------------------------------------------------
void vtkContourRepresentation::GetNodePolyData( vtkPolyData* poly )
{
  poly->Initialize();
  int count = this->GetNumberOfNodes();

  if ( count == 0 )
  {
    return;
  }

  vtkPoints *points = vtkPoints::New();
  vtkCellArray *lines = vtkCellArray::New();

  points->SetNumberOfPoints( count );
  vtkIdType numLines = count;

  if ( this->ClosedLoop )
  {
    numLines++;
  }

  vtkIdType *lineIndices = new vtkIdType[numLines];

  int i;
  vtkIdType index = 0;
  double pos[3];

  for ( i = 0; i < this->GetNumberOfNodes(); ++i )
  {
    // Add the node
    this->GetNthNodeWorldPosition( i, pos );
    points->InsertPoint( index, pos );
    lineIndices[index] = index;
    index++;
  }

  if ( this->ClosedLoop )
  {
    lineIndices[index] = 0;
  }

  lines->InsertNextCell( numLines, lineIndices );
  delete [] lineIndices;

  poly->SetPoints( points );
  poly->SetLines( lines );

  points->Delete();
  lines->Delete();
}

//----------------------------------------------------------------------
void vtkContourRepresentation::AddNodeAtPositionInternal( double worldPos[3],
                                                          double worldOrient[9],
                                                          int displayPos[2] )
{
  double dispPos[2];
  dispPos[0] = static_cast<double>(displayPos[0]);
  dispPos[1] = static_cast<double>(displayPos[1]);
  this->AddNodeAtPositionInternal( worldPos, worldOrient, dispPos );
}

//----------------------------------------------------------------------
int vtkContourRepresentation::AddNodeAtWorldPosition( double worldPos[3],
                                                      double worldOrient[9] )
{
  // Check if this is a valid location
  if ( !this->PointPlacer->ValidateWorldPosition( worldPos, worldOrient ) )
  {
    return 0;
  }

  double displayPos[2];
  this->GetRendererComputedDisplayPositionFromWorldPosition(
                          worldPos, worldOrient, displayPos );
  this->AddNodeAtPositionInternal( worldPos, worldOrient, displayPos );

  return 1;
}

//----------------------------------------------------------------------
int vtkContourRepresentation::AddNodeAtWorldPosition(
  double x, double y, double z)
{
  double worldPos[3] = {x, y, z};
  return this->AddNodeAtWorldPosition(worldPos);
}

//----------------------------------------------------------------------
int vtkContourRepresentation::AddNodeAtWorldPosition( double worldPos[3] )
{
  // Check if this is a valid location
  if ( !this->PointPlacer->ValidateWorldPosition( worldPos ) )
  {
    return 0;
  }

  double worldOrient[9] = {1.0,0.0,0.0,
                           0.0,1.0,0.0,
                           0.0,0.0,1.0};

  double displayPos[2];
  this->GetRendererComputedDisplayPositionFromWorldPosition(
                          worldPos, worldOrient, displayPos );
  this->AddNodeAtPositionInternal( worldPos, worldOrient, displayPos );

  return 1;
}

//----------------------------------------------------------------------
int vtkContourRepresentation::AddNodeAtDisplayPosition(double displayPos[2])
{
  double worldPos[3];
  double worldOrient[9] = {1.0,0.0,0.0,
                           0.0,1.0,0.0,
                           0.0,0.0,1.0};

  // Compute the world position from the display position
  // based on the concrete representation's constraints
  // If this is not a valid display location return 0
  if ( !this->PointPlacer->ComputeWorldPosition( this->Renderer,
                                                 displayPos, worldPos,
                                                 worldOrient) )
  {
    return 0;
  }

  this->AddNodeAtPositionInternal( worldPos, worldOrient, displayPos );
  return 1;
}
//----------------------------------------------------------------------
int vtkContourRepresentation::AddNodeAtDisplayPosition(int displayPos[2])
{
  double doubleDisplayPos[2];
  doubleDisplayPos[0] = displayPos[0];
  doubleDisplayPos[1] = displayPos[1];
  return this->AddNodeAtDisplayPosition( doubleDisplayPos );

}
//----------------------------------------------------------------------
int vtkContourRepresentation::AddNodeAtDisplayPosition(int X, int Y)
{
  double displayPos[2];
  displayPos[0] = X;
  displayPos[1] = Y;
  return this->AddNodeAtDisplayPosition( displayPos );

}

//----------------------------------------------------------------------
int vtkContourRepresentation::ActivateNode( double displayPos[2] )
{
  this->BuildLocator();
  // Find closest node to this display pos that
  // is within PixelTolerance
  double dPos[3] = {displayPos[0],displayPos[1],0};
  double closestDistance2 = VTK_DOUBLE_MAX;
  int closestNode = this->Locator->FindClosestPointWithinRadius(
    this->PixelTolerance,dPos,closestDistance2);
  if ( closestNode != this->ActiveNode )
  {
    this->ActiveNode = closestNode;
    this->NeedToRender = 1;
  }
  return ( this->ActiveNode >= 0 );
}
//----------------------------------------------------------------------
int vtkContourRepresentation::ActivateNode( int displayPos[2] )
{
  double doubleDisplayPos[2];

  doubleDisplayPos[0] = displayPos[0];
  doubleDisplayPos[1] = displayPos[1];
  return this->ActivateNode( doubleDisplayPos );
}

//----------------------------------------------------------------------
int vtkContourRepresentation::ActivateNode( int X, int Y )
{
  double doubleDisplayPos[2];

  doubleDisplayPos[0] = X;
  doubleDisplayPos[1] = Y;
  return this->ActivateNode( doubleDisplayPos );
}


//----------------------------------------------------------------------
int vtkContourRepresentation::SetActiveNodeToWorldPosition( double worldPos[3],
                                                            double worldOrient[9] )
{
  if ( this->ActiveNode < 0 ||
       static_cast<unsigned int>(this->ActiveNode) >= this->Internal->Nodes.size() )
  {
    return 0;
  }

  // Check if this is a valid location
  if ( !this->PointPlacer->ValidateWorldPosition( worldPos, worldOrient ) )
  {
    return 0;
  }

  this->SetNthNodeWorldPositionInternal( this->ActiveNode,
                                         worldPos,
                                         worldOrient );
  return 1;
}

//----------------------------------------------------------------------
int vtkContourRepresentation::SetActiveNodeToWorldPosition( double worldPos[3] )
{
  if ( this->ActiveNode < 0 ||
       static_cast<unsigned int>(this->ActiveNode) >= this->Internal->Nodes.size() )
  {
    return 0;
  }

  // Check if this is a valid location
  if ( !this->PointPlacer->ValidateWorldPosition( worldPos ) )
  {
    return 0;
  }

  double worldOrient[9] = {1.0,0.0,0.0,
                           0.0,1.0,0.0,
                           0.0,0.0,1.0};

  this->SetNthNodeWorldPositionInternal( this->ActiveNode,
                                         worldPos,
                                         worldOrient );
  return 1;
}

//----------------------------------------------------------------------
int vtkContourRepresentation::SetActiveNodeToDisplayPosition( double displayPos[2] )
{
  if ( this->ActiveNode < 0 ||
       static_cast<unsigned int>(this->ActiveNode) >= this->Internal->Nodes.size() )
  {
    return 0;
  }

  double worldPos[3];
  double worldOrient[9] = {1.0,0.0,0.0,
                           0.0,1.0,0.0,
                           0.0,0.0,1.0};

  // Compute the world position from the display position
  // based on the concrete representation's constraints
  // If this is not a valid display location return 0
  if ( !this->PointPlacer->ComputeWorldPosition( this->Renderer,
                                                 displayPos, worldPos,
                                                 worldOrient ) )
  {
    return 0;
  }

  this->SetNthNodeWorldPositionInternal( this->ActiveNode,
                                         worldPos,
                                         worldOrient );
  return 1;
}
//----------------------------------------------------------------------
int vtkContourRepresentation::SetActiveNodeToDisplayPosition( int displayPos[2] )
{
  double doubleDisplayPos[2];
  doubleDisplayPos[0] = displayPos[0];
  doubleDisplayPos[1] = displayPos[1];
  return this->SetActiveNodeToDisplayPosition( doubleDisplayPos );
}

//----------------------------------------------------------------------
int vtkContourRepresentation::SetActiveNodeToDisplayPosition( int X, int Y )
{
  double doubleDisplayPos[2];
  doubleDisplayPos[0] = X;
  doubleDisplayPos[1] = Y;
  return this->SetActiveNodeToDisplayPosition( doubleDisplayPos );
}

//----------------------------------------------------------------------
int vtkContourRepresentation::ToggleActiveNodeSelected()
{
if ( this->ActiveNode < 0 ||
    static_cast<unsigned int>(this->ActiveNode) >= this->Internal->Nodes.size() )
{
  // Failed to toggle the value
  return 0;
}

  this->Internal->Nodes[this->ActiveNode]->Selected =
    this->Internal->Nodes[this->ActiveNode]->Selected ? 0 : 1;
  this->NeedToRender = 1;
  this->Modified();
  return 1;
}

//----------------------------------------------------------------------
int vtkContourRepresentation::GetNthNodeSelected(int n)
{
  if ( n < 0 ||
      static_cast<unsigned int>(n) >= this->Internal->Nodes.size() )
  {
    // This case is considered not Selected.
    return 0;
  }

  return this->Internal->Nodes[n]->Selected;
}

//----------------------------------------------------------------------
int vtkContourRepresentation::SetNthNodeSelected(int n)
{
  if ( n < 0 ||
    static_cast<unsigned int>(n) >= this->Internal->Nodes.size() )
  {
    // Failed.
    return 0;
  }
  int val =  n > 0 ? 1 : 0;
  if(this->Internal->Nodes[n]->Selected != val)
  {
    this->Internal->Nodes[n]->Selected = val;
    this->NeedToRender = 1;
    this->Modified();
  }
  return 1;
}

//----------------------------------------------------------------------
int vtkContourRepresentation::GetActiveNodeSelected()
{
  return this->GetNthNodeSelected(this->ActiveNode);
}

//----------------------------------------------------------------------
int vtkContourRepresentation::GetActiveNodeWorldPosition( double pos[3] )
{
  return this->GetNthNodeWorldPosition( this->ActiveNode, pos );
}

//----------------------------------------------------------------------
int vtkContourRepresentation::GetActiveNodeWorldOrientation( double orient[9] )
{
  return this->GetNthNodeWorldOrientation( this->ActiveNode, orient );
}

//----------------------------------------------------------------------
int vtkContourRepresentation::GetActiveNodeDisplayPosition( double pos[2] )
{
  return this->GetNthNodeDisplayPosition( this->ActiveNode, pos );
}

//----------------------------------------------------------------------
int vtkContourRepresentation::GetNumberOfNodes()
{
  return static_cast<int>(this->Internal->Nodes.size());
}

//----------------------------------------------------------------------
int vtkContourRepresentation::GetNumberOfIntermediatePoints(int n)
{
  if ( n < 0 ||
       static_cast<unsigned int>(n) >= this->Internal->Nodes.size() )
  {
    return 0;
  }

  return static_cast<int>(this->Internal->Nodes[n]->Points.size());
}

//----------------------------------------------------------------------
int vtkContourRepresentation::GetIntermediatePointWorldPosition(int n,
                                                                int idx,
                                                                double point[3])
{
  if ( n < 0 ||
       static_cast<unsigned int>(n) >= this->Internal->Nodes.size() )
  {
    return 0;
  }

  if ( idx < 0 ||
       static_cast<unsigned int>(idx) >= this->Internal->Nodes[n]->Points.size() )
  {
    return 0;
  }

  point[0] = this->Internal->Nodes[n]->Points[idx]->WorldPosition[0];
  point[1] = this->Internal->Nodes[n]->Points[idx]->WorldPosition[1];
  point[2] = this->Internal->Nodes[n]->Points[idx]->WorldPosition[2];

  return 1;
}

//----------------------------------------------------------------------
// The display position for a given world position must be re-computed
// from the world positions... It should not be queried from the renderer
// whose camera position may have changed
int vtkContourRepresentation::GetNthNodeDisplayPosition(
                           int n, double displayPos[2] )
{
  if ( n < 0 ||
       static_cast<unsigned int>(n) >= this->Internal->Nodes.size() )
  {
    return 0;
  }

  double pos[4];
  pos[0] = this->Internal->Nodes[n]->WorldPosition[0];
  pos[1] = this->Internal->Nodes[n]->WorldPosition[1];
  pos[2] = this->Internal->Nodes[n]->WorldPosition[2];
  pos[3] = 1.0;

  this->Renderer->SetWorldPoint( pos );
  this->Renderer->WorldToDisplay();
  this->Renderer->GetDisplayPoint( pos );

  displayPos[0] = pos[0];
  displayPos[1] = pos[1];
  return 1;
}

//----------------------------------------------------------------------
int vtkContourRepresentation::GetNthNodeWorldPosition( int n, double worldPos[3] )
{
  if ( vtkContourRepresentationNode *node = this->GetNthNode(n) )
  {
    worldPos[0] = node->WorldPosition[0];
    worldPos[1] = node->WorldPosition[1];
    worldPos[2] = node->WorldPosition[2];
    return 1;
  }

  return 0;
}

//----------------------------------------------------------------------
vtkContourRepresentationNode * vtkContourRepresentation::GetNthNode( int n )
{
  if ( n < 0 ||
       static_cast<unsigned int>(n) >= this->Internal->Nodes.size() )
  {
    return nullptr;
  }
  return this->Internal->Nodes[n];
}

//----------------------------------------------------------------------
int vtkContourRepresentation::GetNthNodeWorldOrientation( int n, double worldOrient[9] )
{
  if ( n < 0 ||
       static_cast<unsigned int>(n) >= this->Internal->Nodes.size() )
  {
    return 0;
  }

  memcpy( worldOrient, this->Internal->Nodes[n]->WorldOrientation, 9*sizeof(double) );
  return 1;
}

//----------------------------------------------------------------------
void vtkContourRepresentation::SetNthNodeWorldPositionInternal( int n, double worldPos[3],
                                                                double worldOrient[9] )
{
  this->Internal->Nodes[n]->WorldPosition[0] = worldPos[0];
  this->Internal->Nodes[n]->WorldPosition[1] = worldPos[1];
  this->Internal->Nodes[n]->WorldPosition[2] = worldPos[2];

  this->GetRendererComputedDisplayPositionFromWorldPosition(
        worldPos, worldOrient, this->Internal->Nodes[n]->NormalizedDisplayPosition );
  this->Renderer->DisplayToNormalizedDisplay(
      this->Internal->Nodes[n]->NormalizedDisplayPosition[0],
      this->Internal->Nodes[n]->NormalizedDisplayPosition[1] );

  memcpy(this->Internal->Nodes[n]->WorldOrientation, worldOrient, 9*sizeof(double) );

  this->UpdateLines( n );
  this->NeedToRender = 1;
}

//----------------------------------------------------------------------
int vtkContourRepresentation::SetNthNodeWorldPosition( int n, double worldPos[3],
                                                       double worldOrient[9] )
{
  if ( n < 0 ||
       static_cast<unsigned int>(n) >= this->Internal->Nodes.size() )
  {
    return 0;
  }

  // Check if this is a valid location
  if ( !this->PointPlacer->ValidateWorldPosition( worldPos, worldOrient ) )
  {
    return 0;
  }

  this->SetNthNodeWorldPositionInternal( n, worldPos, worldOrient );
  return 1;
}

//----------------------------------------------------------------------
int vtkContourRepresentation::SetNthNodeWorldPosition( int n, double worldPos[3] )
{
  if ( n < 0 ||
       static_cast<unsigned int>(n) >= this->Internal->Nodes.size() )
  {
    return 0;
  }

  // Check if this is a valid location
  if ( !this->PointPlacer->ValidateWorldPosition( worldPos ) )
  {
    return 0;
  }

  double worldOrient[9] = {1.0,0.0,0.0,
                           0.0,1.0,0.0,
                           0.0,0.0,1.0};

  this->SetNthNodeWorldPositionInternal( n, worldPos, worldOrient );
  return 1;
}

//----------------------------------------------------------------------
int vtkContourRepresentation::SetNthNodeDisplayPosition( int n, double displayPos[2] )
{
  double worldPos[3];
  double worldOrient[9] = {1.0,0.0,0.0,
                           0.0,1.0,0.0,
                           0.0,0.0,1.0};

  // Compute the world position from the display position
  // based on the concrete representation's constraints
  // If this is not a valid display location return 0
  if ( !this->PointPlacer->ComputeWorldPosition( this->Renderer,
                                                 displayPos, worldPos,
                                                 worldOrient) )
  {
    return 0;
  }

  return this->SetNthNodeWorldPosition( n, worldPos, worldOrient );
}

//----------------------------------------------------------------------
int vtkContourRepresentation::SetNthNodeDisplayPosition( int n, int displayPos[2] )
{
  double doubleDisplayPos[2];
  doubleDisplayPos[0] = displayPos[0];
  doubleDisplayPos[1] = displayPos[1];
  return this->SetNthNodeDisplayPosition( n, doubleDisplayPos );
}

//----------------------------------------------------------------------
int vtkContourRepresentation::SetNthNodeDisplayPosition( int n, int X, int Y )
{
  double doubleDisplayPos[2];
  doubleDisplayPos[0] = X;
  doubleDisplayPos[1] = Y;
  return this->SetNthNodeDisplayPosition( n, doubleDisplayPos );
}

//----------------------------------------------------------------------
int vtkContourRepresentation::FindClosestPointOnContour( int X, int Y,
                                                         double closestWorldPos[3],
                                                         int *idx )
{
  // Make a line out of this viewing ray
  double p1[4], p2[4], *p3=nullptr, *p4=nullptr;

  double tmp1[4], tmp2[4];
  tmp1[0] = X;
  tmp1[1] = Y;
  tmp1[2] = 0.0;
  this->Renderer->SetDisplayPoint( tmp1 );
  this->Renderer->DisplayToWorld();
  this->Renderer->GetWorldPoint(p1);

  tmp1[2] = 1.0;
  this->Renderer->SetDisplayPoint( tmp1 );
  this->Renderer->DisplayToWorld();
  this->Renderer->GetWorldPoint(p2);

  double closestDistance2 = VTK_DOUBLE_MAX;
  int closestNode=0;

  // compute a world tolerance based on pixel
  // tolerance on the focal plane
  double fp[4];
  this->Renderer->GetActiveCamera()->GetFocalPoint(fp);
  fp[3] = 1.0;
  this->Renderer->SetWorldPoint(fp);
  this->Renderer->WorldToDisplay();
  this->Renderer->GetDisplayPoint(tmp1);

  tmp1[0] = 0;
  tmp1[1] = 0;
  this->Renderer->SetDisplayPoint(tmp1);
  this->Renderer->DisplayToWorld();
  this->Renderer->GetWorldPoint(tmp2);

  tmp1[0] = this->PixelTolerance;
  this->Renderer->SetDisplayPoint(tmp1);
  this->Renderer->DisplayToWorld();
  this->Renderer->GetWorldPoint(tmp1);

  double wt2 = vtkMath::Distance2BetweenPoints(tmp1, tmp2);

  // Now loop through all lines and look for closest one within tolerance
  for(unsigned int i=0;i<this->Internal->Nodes.size();i++)
  {
    for (unsigned int j=0;j<=this->Internal->Nodes[i]->Points.size();j++)
    {
      if ( j == 0 )
      {
        p3 = this->Internal->Nodes[i]->WorldPosition;
        if ( !this->Internal->Nodes[i]->Points.empty() )
        {
          p4 = this->Internal->Nodes[i]->Points[j]->WorldPosition;
        }
        else
        {
          if ( i < this->Internal->Nodes.size() - 1 )
          {
            p4 = this->Internal->Nodes[i+1]->WorldPosition;
          }
          else if ( this->ClosedLoop )
          {
            p4 = this->Internal->Nodes[0]->WorldPosition;
          }
        }
      }
      else if ( j == this->Internal->Nodes[i]->Points.size() )
      {
        p3 = this->Internal->Nodes[i]->Points[j-1]->WorldPosition;
        if ( i < this->Internal->Nodes.size() - 1 )
        {
          p4 = this->Internal->Nodes[i+1]->WorldPosition;
        }
        else if ( this->ClosedLoop )
        {
          p4 = this->Internal->Nodes[0]->WorldPosition;
        }
        else
        {
          // Shouldn't be able to get here (only if we don't have
          // a closed loop but we do have intermediate points after
          // the last node - contradictary conditions)
          continue;
        }
      }
      else
      {
        p3 = this->Internal->Nodes[i]->Points[j-1]->WorldPosition;
        p4 = this->Internal->Nodes[i]->Points[j]->WorldPosition;
      }

      // Now we have the four points - check closest intersection
      double u, v;

      if ( vtkLine::Intersection( p1, p2, p3, p4, u, v ) )
      {
        double p5[3], p6[3];
        p5[0] = p1[0] + u*(p2[0]-p1[0]);
        p5[1] = p1[1] + u*(p2[1]-p1[1]);
        p5[2] = p1[2] + u*(p2[2]-p1[2]);

        p6[0] = p3[0] + v*(p4[0]-p3[0]);
        p6[1] = p3[1] + v*(p4[1]-p3[1]);
        p6[2] = p3[2] + v*(p4[2]-p3[2]);

        double d = vtkMath::Distance2BetweenPoints(p5, p6);

        if ( d < wt2 && d < closestDistance2 )
        {
          closestWorldPos[0] = p6[0];
          closestWorldPos[1] = p6[1];
          closestWorldPos[2] = p6[2];
          closestDistance2 = d;
          closestNode = static_cast<int>(i);
        }
      }
      else
      {
        double d = vtkLine::DistanceToLine( p3, p1, p2 );
        if ( d < wt2 && d < closestDistance2 )
        {
          closestWorldPos[0] = p3[0];
          closestWorldPos[1] = p3[1];
          closestWorldPos[2] = p3[2];
          closestDistance2 = d;
          closestNode = static_cast<int>(i);
        }

        d = vtkLine::DistanceToLine( p4, p1, p2 );
        if ( d < wt2 && d < closestDistance2 )
        {
          closestWorldPos[0] = p4[0];
          closestWorldPos[1] = p4[1];
          closestWorldPos[2] = p4[2];
          closestDistance2 = d;
          closestNode = static_cast<int>(i);
        }
      }
    }
  }

  if ( closestDistance2 < VTK_DOUBLE_MAX )
  {
    if ( closestNode < this->GetNumberOfNodes() -1 )
    {
      *idx = closestNode+1;
      return 1;
    }
    else if ( this->ClosedLoop )
    {
      *idx = 0;
      return 1;
    }
  }

  return 0;
}

//----------------------------------------------------------------------
int vtkContourRepresentation::AddNodeOnContour( int X, int Y )
{
  int idx;

  double worldPos[3];
  double worldOrient[9] = {1.0,0.0,0.0,
                           0.0,1.0,0.0,
                           0.0,0.0,1.0};

  // Compute the world position from the display position
  // based on the concrete representation's constraints
  // If this is not a valid display location return 0
  double displayPos[2];
  displayPos[0] = X;
  displayPos[1] = Y;
  if ( !this->PointPlacer->ComputeWorldPosition( this->Renderer,
                                                 displayPos, worldPos,
                                                 worldOrient) )
  {
    return 0;
  }

  double pos[3];
  if ( !this->FindClosestPointOnContour( X, Y, pos, &idx ) )
  {
    return 0;
  }

  if ( !this->PointPlacer->ComputeWorldPosition( this->Renderer,
                                                 displayPos,
                                                 pos,
                                                 worldPos,
                                                 worldOrient) )
  {
    return 0;
  }

  // Add a new point at this position
  vtkContourRepresentationNode *node = new vtkContourRepresentationNode;
  node->WorldPosition[0] = worldPos[0];
  node->WorldPosition[1] = worldPos[1];
  node->WorldPosition[2] = worldPos[2];
  node->Selected = 0;

  this->GetRendererComputedDisplayPositionFromWorldPosition(
          worldPos, worldOrient, node->NormalizedDisplayPosition );
  this->Renderer->DisplayToNormalizedDisplay(
         node->NormalizedDisplayPosition[0],
         node->NormalizedDisplayPosition[1] );

  memcpy(node->WorldOrientation, worldOrient, 9*sizeof(double) );

  this->Internal->Nodes.insert(this->Internal->Nodes.begin() + idx, node);

  this->UpdateLines( idx );
  this->NeedToRender = 1;

  return 1;
}

//----------------------------------------------------------------------
int vtkContourRepresentation::DeleteNthNode( int n )
{
  if ( n < 0 ||
       static_cast<unsigned int>(n) >= this->Internal->Nodes.size() )
  {
    return 0;
  }

  for (unsigned int j=0;j<this->Internal->Nodes[n]->Points.size();j++)
  {
    delete this->Internal->Nodes[n]->Points[j];
  }
  this->Internal->Nodes[n]->Points.clear();
  delete this->Internal->Nodes[n];
  this->Internal->Nodes.erase( this->Internal->Nodes.begin() + n );
  if ( n )
  {
    this->UpdateLines(n-1);
  }
  else
  {
    this->UpdateLines(this->GetNumberOfNodes()-1);
  }

  this->NeedToRender = 1;
  return 1;
}

//----------------------------------------------------------------------
int vtkContourRepresentation::DeleteActiveNode()
{
  return this->DeleteNthNode( this->ActiveNode );
}

//----------------------------------------------------------------------
int vtkContourRepresentation::DeleteLastNode()
{
  return this->DeleteNthNode(
    static_cast<int>(this->Internal->Nodes.size()) - 1 );
}

//----------------------------------------------------------------------
void vtkContourRepresentation::SetClosedLoop( vtkTypeBool val )
{
  if ( this->ClosedLoop != val )
  {
    this->ClosedLoop = val;
    this->UpdateLines(this->GetNumberOfNodes()-1);
    this->NeedToRender = 1;
    this->Modified();
  }
}

//----------------------------------------------------------------------
void vtkContourRepresentation::UpdateLines( int index )
{
  int indices[2];

  if (this->LineInterpolator)
  {
    vtkIntArray *arr = vtkIntArray::New();
    this->LineInterpolator->GetSpan( index, arr, this );

    int nNodes = arr->GetNumberOfTuples();
    for (int i = 0; i < nNodes; i++)
    {
      arr->GetTypedTuple( i, indices );
      this->UpdateLine( indices[0], indices[1] );
    }
    arr->Delete();
  }

  // A check to make sure that we have no line segments in
  // the last node if the loop is not closed
  if ( !this->ClosedLoop && this->GetNumberOfNodes() > 0 )
  {
    int idx = static_cast<int>(this->Internal->Nodes.size()) -1;
    for (unsigned int j=0;j<this->Internal->Nodes[idx]->Points.size();j++)
    {
      delete this->Internal->Nodes[idx]->Points[j];
    }
    this->Internal->Nodes[idx]->Points.clear();
  }

  this->BuildLines();
  this->RebuildLocator = true;
}

//----------------------------------------------------------------------
int vtkContourRepresentation::AddIntermediatePointWorldPosition( int n,
                                                                 double pos[3] )
{
  return this->AddIntermediatePointWorldPosition(n, pos, 0);
}

//----------------------------------------------------------------------
int vtkContourRepresentation
::AddIntermediatePointWorldPosition( int n, double pos[3], vtkIdType ptId )
{
  if ( n < 0 ||
       static_cast<unsigned int>(n) >= this->Internal->Nodes.size() )
  {
    return 0;
  }

  vtkContourRepresentationPoint *point = new vtkContourRepresentationPoint;
  point->WorldPosition[0] = pos[0];
  point->WorldPosition[1] = pos[1];
  point->WorldPosition[2] = pos[2];
  point->PointId = ptId;

  double worldOrient[9] = {1.0,0.0,0.0,
                           0.0,1.0,0.0,
                           0.0,0.0,1.0};

  this->GetRendererComputedDisplayPositionFromWorldPosition(
                          pos, worldOrient, point->NormalizedDisplayPosition );
  this->Renderer->DisplayToNormalizedDisplay(
      point->NormalizedDisplayPosition[0],
      point->NormalizedDisplayPosition[1] );

  this->Internal->Nodes[n]->Points.push_back(point);
  return 1;
}

//----------------------------------------------------------------------
int vtkContourRepresentation::GetNthNodeSlope( int n, double slope[3] )
{
  if ( n < 0 ||
       static_cast<unsigned int>(n) >= this->Internal->Nodes.size() )
  {
    return 0;
  }

  int idx1, idx2;

  if ( n == 0 && !this->ClosedLoop )
  {
    idx1 = 0;
    idx2 = 1;
  }
  else if ( n == this->GetNumberOfNodes()-1 && !this->ClosedLoop )
  {
    idx1 = this->GetNumberOfNodes()-2;
    idx2 = idx1+1;
  }
  else
  {
    idx1 = n - 1;
    idx2 = n + 1;

    if ( idx1 < 0 )
    {
      idx1 += this->GetNumberOfNodes();
    }
    if ( idx2 >= this->GetNumberOfNodes() )
    {
      idx2 -= this->GetNumberOfNodes();
    }
  }

  slope[0] =
    this->Internal->Nodes[idx2]->WorldPosition[0] -
    this->Internal->Nodes[idx1]->WorldPosition[0];
  slope[1] =
    this->Internal->Nodes[idx2]->WorldPosition[1] -
    this->Internal->Nodes[idx1]->WorldPosition[1];
  slope[2] =
    this->Internal->Nodes[idx2]->WorldPosition[2] -
    this->Internal->Nodes[idx1]->WorldPosition[2];

  vtkMath::Normalize( slope );
  return 1;
}

//----------------------------------------------------------------------
void vtkContourRepresentation::UpdateLine( int idx1, int idx2 )
{
  if ( !this->LineInterpolator )
  {
    return;
  }

  // Clear all the points at idx1
  for (unsigned int j=0;j<this->Internal->Nodes[idx1]->Points.size();j++)
  {
    delete this->Internal->Nodes[idx1]->Points[j];
  }
  this->Internal->Nodes[idx1]->Points.clear();

  this->LineInterpolator->InterpolateLine( this->Renderer,
                                           this,
                                           idx1, idx2 );
}

//----------------------------------------------------------------------
int vtkContourRepresentation::ComputeInteractionState(
    int vtkNotUsed(X), int vtkNotUsed(Y), int vtkNotUsed(modified))
{
  return this->InteractionState;
}

//---------------------------------------------------------------------
int vtkContourRepresentation::UpdateContour()
{
  this->PointPlacer->UpdateInternalState();

  //even if just the camera has moved we need to mark the locator
  //as needing to be rebuilt
  if ( this->Locator->GetMTime() < this->Renderer->GetActiveCamera()->GetMTime())
  {
    this->RebuildLocator = true;
  }

  if ( this->ContourBuildTime > this->PointPlacer->GetMTime())
  {
    // Contour does not need to be rebuilt
    return 0;
  }

  unsigned int i;
  for(i=0; i<this->Internal->Nodes.size(); i++)
  {
    this->PointPlacer->
      UpdateWorldPosition( this->Renderer,
                           this->Internal->Nodes[i]->WorldPosition,
                           this->Internal->Nodes[i]->WorldOrientation );
  }

  for(i=0; (i+1)<this->Internal->Nodes.size(); i++)
  {
    this->UpdateLine(i, i+1);
  }

  if ( this->ClosedLoop )
  {
    this->UpdateLine( static_cast<int>(this->Internal->Nodes.size())-1, 0);
  }
  this->BuildLines();
  this->RebuildLocator = true;

  this->ContourBuildTime.Modified();

  return 1;
}

//----------------------------------------------------------------------
void vtkContourRepresentation
::GetRendererComputedDisplayPositionFromWorldPosition( double worldPos[3],
                                double worldOrient[9], int displayPos[2] )
{
  double dispPos[2];
  dispPos[0] = static_cast<double>(displayPos[0]);
  dispPos[1] = static_cast<double>(displayPos[1]);
  this->GetRendererComputedDisplayPositionFromWorldPosition( worldPos,
                                                worldOrient, dispPos );
  displayPos[0] = static_cast<int>(dispPos[0]);
  displayPos[1] = static_cast<int>(dispPos[1]);
}

//----------------------------------------------------------------------
void vtkContourRepresentation
::GetRendererComputedDisplayPositionFromWorldPosition( double worldPos[3],
                                double * vtkNotUsed(worldOrient[9]), double displayPos[2] )
{
  double pos[4];
  pos[0] = worldPos[0];
  pos[1] = worldPos[1];
  pos[2] = worldPos[2];
  pos[3] = 1.0;

  this->Renderer->SetWorldPoint( pos );
  this->Renderer->WorldToDisplay();
  this->Renderer->GetDisplayPoint( pos );

  displayPos[0] = pos[0];
  displayPos[1] = pos[1];
}

//----------------------------------------------------------------------
void vtkContourRepresentation::Initialize( vtkPolyData * pd )
{
  // For backward compatibility
  this->InitializeContour(pd, nullptr);
}

//----------------------------------------------------------------------
void vtkContourRepresentation
::Initialize( vtkPolyData * pd, vtkIdList *nodeIds )
{
  if (!nodeIds)
  {
    this->Initialize(pd);
    return;
  }

  this->InitializeContour(pd, nodeIds);
}

//----------------------------------------------------------------------
void vtkContourRepresentation
::InitializeContour( vtkPolyData * pd, vtkIdList *nodeIds )
{
  vtkPoints *points   = pd->GetPoints();
  vtkIdType nPoints = points->GetNumberOfPoints();
  if (nPoints <= 0)
  {
    return; // Yeah right.. build from nothing !
  }

  // Clear all existing nodes.
  for(unsigned int i=0;i<this->Internal->Nodes.size();i++)
  {
    for (unsigned int j=0;j<this->Internal->Nodes[i]->Points.size();j++)
    {
      delete this->Internal->Nodes[i]->Points[j];
    }
    this->Internal->Nodes[i]->Points.clear();
    delete this->Internal->Nodes[i];
  }
  this->Internal->Nodes.clear();

  vtkPolyData *tmpPoints = vtkPolyData::New();
  tmpPoints->DeepCopy(pd);
  this->Locator->SetDataSet(tmpPoints);
  tmpPoints->Delete();

  //reserver space in memory to speed up vector push_back
  this->Internal->Nodes.reserve(nPoints);

  vtkIdList *pointIds = pd->GetCell(0)->GetPointIds();

  // Get the worldOrient from the point placer
  double ref[3], displayPos[2], worldPos[3];
  double worldOrient[9] = {1.0,0.0,0.0,
                           0.0,1.0,0.0,
                           0.0,0.0,1.0};
  ref[0] = 0.0; ref[1] = 0.0; ref[2] = 0.0;
  displayPos[0] = 0.0; displayPos[1] = 0.0;
  this->PointPlacer->ComputeWorldPosition(this->Renderer,
                                 displayPos, ref, worldPos, worldOrient );

  // Add nodes without calling rebuild lines
  // to improve performance dramatically(~15x) on large datasets
  double *pos;
  for ( vtkIdType i=0; i < nPoints; i++ )
  {
    pos = points->GetPoint( i );
    this->GetRendererComputedDisplayPositionFromWorldPosition(
                          pos, worldOrient, displayPos );

    // Add a new point at this position
    vtkContourRepresentationNode *node = new vtkContourRepresentationNode;
    node->WorldPosition[0] = pos[0];
    node->WorldPosition[1] = pos[1];
    node->WorldPosition[2] = pos[2];
    node->Selected = 0;

    // Give the point placer a chance to update the node
    if (nodeIds && nodeIds->GetNumberOfIds() == nPoints)
    {
      this->PointPlacer->UpdateNodeWorldPosition( pos, nodeIds->GetId(i) );
    }

    node->NormalizedDisplayPosition[0] = displayPos[0];
    node->NormalizedDisplayPosition[1] = displayPos[1];

    this->Renderer->DisplayToNormalizedDisplay(
      node->NormalizedDisplayPosition[0],
      node->NormalizedDisplayPosition[1] );

    memcpy(node->WorldOrientation, worldOrient, 9*sizeof(double) );

    this->Internal->Nodes.push_back(node);

    if ( this->LineInterpolator && this->GetNumberOfNodes() > 1 )
    {
      // Give the line interpolator a chance to update the node.
      int didNodeChange = this->LineInterpolator->UpdateNode(
        this->Renderer, this,
        node->WorldPosition, this->GetNumberOfNodes()-1 );

      // Give the point placer a chance to validate the updated node. If its
      // not valid, discard the LineInterpolator's change.
      if ( didNodeChange && !this->PointPlacer->ValidateWorldPosition(
                node->WorldPosition, worldOrient ) )
      {
        node->WorldPosition[0] = worldPos[0];
        node->WorldPosition[1] = worldPos[1];
        node->WorldPosition[2] = worldPos[2];
      }
    }
  }

  if ( pointIds->GetNumberOfIds() > nPoints )
  {
    this->ClosedLoopOn();
  }

  // Update the contour representation from the nodes using the line interpolator
  for (vtkIdType i=1; i <= nPoints; ++i)
  {
    this->UpdateLines(i);
  }
  this->BuildRepresentation();

  // Show the contour.
  this->VisibilityOn();
}

//----------------------------------------------------------------------
void vtkContourRepresentation::BuildLocator()
{
if (!this->RebuildLocator && !this->NeedToRender)
{
    //rebuild if rebuildLocator or needtorender are true
    return;
}

  vtkIdType size = (vtkIdType)this->Internal->Nodes.size();
  vtkPoints *points = vtkPoints::New();
  points->SetNumberOfPoints(size);

  //setup up the matrixes needed to transform
  //world to display. We are going to do this manually
  // as calling the renderer will create a new matrix for each call
  vtkMatrix4x4 *matrix = vtkMatrix4x4::New();
  matrix->DeepCopy(this->Renderer->GetActiveCamera()
    ->GetCompositeProjectionTransformMatrix(
    this->Renderer->GetTiledAspectRatio(),0,1));

  //viewport info
  double viewPortRatio[2];
  int sizex,sizey;

  /* get physical window dimensions */
  if ( this->Renderer->GetVTKWindow() )
  {
    double *viewPort = this->Renderer->GetViewport();
    sizex = this->Renderer->GetVTKWindow()->GetSize()[0];
    sizey = this->Renderer->GetVTKWindow()->GetSize()[1];
    viewPortRatio[0] = (sizex*(viewPort[2]-viewPort[0])) / 2.0 +
        sizex*viewPort[0];
    viewPortRatio[1] = (sizey*(viewPort[3]-viewPort[1])) / 2.0 +
        sizey*viewPort[1];
  }
  else
  {
    //can't compute the locator without a vtk window
    return;
  }

  double     view[4];
  double pos[3] = {0,0,0};
  double *wp;
  for(vtkIdType i=0; i < size; ++i)
  {
    wp = this->Internal->Nodes[i]->WorldPosition;
    pos[0] = this->Internal->Nodes[i]->WorldPosition[0];
    pos[1] = this->Internal->Nodes[i]->WorldPosition[1];
    pos[2] = this->Internal->Nodes[i]->WorldPosition[2];

    //convert from world to view
    view[0] = wp[0]*matrix->Element[0][0] + wp[1]*matrix->Element[0][1] +
      wp[2]*matrix->Element[0][2] + matrix->Element[0][3];
    view[1] = wp[0]*matrix->Element[1][0] + wp[1]*matrix->Element[1][1] +
      wp[2]*matrix->Element[1][2] + matrix->Element[1][3];
    view[2] = wp[0]*matrix->Element[2][0] + wp[1]*matrix->Element[2][1] +
      wp[2]*matrix->Element[2][2] + matrix->Element[2][3];
    view[3] = wp[0]*matrix->Element[3][0] + wp[1]*matrix->Element[3][1] +
      wp[2]*matrix->Element[3][2] + matrix->Element[3][3];
    if (view[3] != 0.0)
    {
      pos[0] = view[0]/view[3];
      pos[1] = view[1]/view[3];
    }

    //now from view to display
    pos[0] = (pos[0] + 1.0) * viewPortRatio[0];
    pos[1] = (pos[1] + 1.0) * viewPortRatio[1];
    pos[2] = 0;

    points->InsertPoint(i,pos);
  }

  matrix->Delete();
  vtkPolyData *tmp = vtkPolyData::New();
  tmp->SetPoints(points);
  this->Locator->SetDataSet(tmp);
  tmp->FastDelete();
  points->FastDelete();

  //we fully updated the display locator
  this->RebuildLocator = false;
}

//----------------------------------------------------------------------
void vtkContourRepresentation::SetShowSelectedNodes(vtkTypeBool flag )
{
  if (this->ShowSelectedNodes != flag)
  {
    this->ShowSelectedNodes = flag;
    this->Modified();
  }
}

//----------------------------------------------------------------------
void vtkContourRepresentation::PrintSelf(ostream& os, vtkIndent indent)
{
  //Superclass typedef defined in vtkTypeMacro() found in vtkSetGet.h
  this->Superclass::PrintSelf(os,indent);

  os << indent << "Pixel Tolerance: " << this->PixelTolerance <<"\n";
  os << indent << "World Tolerance: " << this->WorldTolerance <<"\n";

  os << indent << "Closed Loop: " << (this->ClosedLoop ? "On\n" : "Off\n");
  os << indent << "ShowSelectedNodes: " << this->ShowSelectedNodes <<endl;
  os << indent << "Rebuild Locator: " <<
     (this->RebuildLocator ? "On" : "Off") << endl;

  os << indent << "Current Operation: ";
  if ( this->CurrentOperation == vtkContourRepresentation::Inactive )
  {
    os << "Inactive\n";
  }
  else
  {
    os << "Translate\n";
  }

  os << indent << "Line Interpolator: " << this->LineInterpolator << "\n";
  os << indent << "Point Placer: " << this->PointPlacer << "\n";

}