vtkResliceCursorRepresentation.cxx

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

  Program:   Visualization Toolkit
  Module:    vtkResliceCursorRepresentation.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 "vtkResliceCursorRepresentation.h"

#include "vtkResliceCursor.h"
#include "vtkResliceCursorPolyDataAlgorithm.h"
#include "vtkHandleRepresentation.h"
#include "vtkCoordinate.h"
#include "vtkRenderer.h"
#include "vtkMath.h"
#include "vtkWindow.h"
#include "vtkPolyData.h"
#include "vtkPolyDataMapper2D.h"
#include "vtkPolyDataMapper.h"
#include "vtkActor2D.h"
#include "vtkTextMapper.h"
#include "vtkTextProperty.h"
#include "vtkTextActor.h"
#include "vtkProperty2D.h"
#include "vtkPointHandleRepresentation2D.h"
#include "vtkObjectFactory.h"
#include "vtkImageReslice.h"
#include "vtkMath.h"
#include "vtkMatrix4x4.h"
#include "vtkImageData.h"
#include "vtkPlaneSource.h"
#include "vtkPlane.h"
#include "vtkLookupTable.h"
#include "vtkScalarsToColors.h"
#include "vtkImageMapToWindowLevelColors.h"
#include "vtkInteractorObserver.h"
#include "vtkActor.h"
#include "vtkTexture.h"
#include "vtkImageActor.h"
#include "vtkCamera.h"
#include "vtkImageMapper3D.h"

#include <sstream>

vtkCxxSetObjectMacro(vtkResliceCursorRepresentation, ColorMap, vtkImageMapToColors);

//----------------------------------------------------------------------
vtkResliceCursorRepresentation::vtkResliceCursorRepresentation()
{
  this->ManipulationMode = None;
  this->Modifier = 0;
  this->Tolerance = 5;
  this->ShowReslicedImage = 1;
  this->RestrictPlaneToVolume = 1;
  this->OriginalWindow           = 1.0;
  this->OriginalLevel            = 0.5;
  this->InitialWindow            = 1.0;
  this->InitialLevel             = 0.5;
  this->CurrentWindow            = 1.0;
  this->CurrentLevel             = 0.5;

  this->ThicknessTextProperty = vtkTextProperty::New();
  this->ThicknessTextProperty->SetBold(1);
  this->ThicknessTextProperty->SetItalic(1);
  this->ThicknessTextProperty->SetShadow(1);
  this->ThicknessTextProperty->SetFontFamilyToArial();
  this->ThicknessTextMapper = vtkTextMapper::New();
  this->ThicknessTextMapper->SetTextProperty(this->ThicknessTextProperty);
  this->ThicknessTextMapper->SetInput("0.0");
  this->ThicknessTextActor = vtkActor2D::New();
  this->ThicknessTextActor->SetMapper(this->ThicknessTextMapper);
  this->ThicknessTextActor->VisibilityOff();

  this->Reslice = NULL;
  this->CreateDefaultResliceAlgorithm();
  this->PlaneSource = vtkPlaneSource::New();

  this->ThicknessLabelFormat = new char[6];
  sprintf(this->ThicknessLabelFormat,"%s","%0.3g");

  this->ResliceAxes        = vtkMatrix4x4::New();
  this->NewResliceAxes     = vtkMatrix4x4::New();
  this->LookupTable        = 0;
  this->ColorMap           = vtkImageMapToColors::New();
  this->Texture            = vtkTexture::New();
  this->Texture->SetInputConnection(
    this->ColorMap->GetOutputPort());
  this->Texture->SetInterpolate(1);
  this->TexturePlaneActor  = vtkActor::New();

  this->LookupTable = this->CreateDefaultLookupTable();

  this->ColorMap->SetLookupTable(this->LookupTable);
  this->ColorMap->SetOutputFormatToRGBA();
  this->ColorMap->PassAlphaToOutputOn();

  vtkPolyDataMapper* texturePlaneMapper = vtkPolyDataMapper::New();
  texturePlaneMapper->SetInputConnection(
    this->PlaneSource->GetOutputPort());
  texturePlaneMapper->SetResolveCoincidentTopologyToPolygonOffset();

  this->Texture->SetQualityTo32Bit();
  this->Texture->MapColorScalarsThroughLookupTableOff();
  this->Texture->SetInterpolate(1);
  this->Texture->RepeatOff();
  this->Texture->SetLookupTable(this->LookupTable);

  this->TexturePlaneActor->SetMapper(texturePlaneMapper);
  this->TexturePlaneActor->SetTexture(this->Texture);
  this->TexturePlaneActor->PickableOn();
  texturePlaneMapper->Delete();

  this->UseImageActor = false;
  this->ImageActor = vtkImageActor::New();
  this->ImageActor->GetMapper()->SetInputConnection(
    this->ColorMap->GetOutputPort());

  // Represent the text: annotation for cursor position and W/L

  this->DisplayText = 1;
  this->TextActor = vtkTextActor::New();
  this->GenerateText();
}

//----------------------------------------------------------------------
vtkResliceCursorRepresentation::~vtkResliceCursorRepresentation()
{
  this->ThicknessTextProperty->Delete();
  this->ThicknessTextMapper->Delete();
  this->ThicknessTextActor->Delete();
  this->SetThicknessLabelFormat(0);
  this->ImageActor->Delete();
  if (this->Reslice)
  {
    this->Reslice->Delete();
  }
  this->PlaneSource->Delete();
  this->ResliceAxes->Delete();
  this->NewResliceAxes->Delete();
  if ( this->LookupTable )
  {
    this->LookupTable->UnRegister(this);
  }
  this->ColorMap->Delete();
  this->Texture->Delete();
  this->TexturePlaneActor->Delete();
  this->TextActor->Delete();
}

//----------------------------------------------------------------------
void vtkResliceCursorRepresentation::SetLookupTable(vtkScalarsToColors *l)
{
  vtkSetObjectBodyMacro(LookupTable, vtkScalarsToColors, l);
  this->LookupTable = l;
  if (this->ColorMap)
  {
    this->ColorMap->SetLookupTable(this->LookupTable);
  }
}

//----------------------------------------------------------------------
char* vtkResliceCursorRepresentation::GetThicknessLabelText()
{
  return this->ThicknessTextMapper->GetInput();
}

//----------------------------------------------------------------------
double* vtkResliceCursorRepresentation::GetThicknessLabelPosition()
{
  return this->ThicknessTextActor->GetPosition();
}

//----------------------------------------------------------------------
void vtkResliceCursorRepresentation::GetThicknessLabelPosition(double pos[3])
{
  this->ThicknessTextActor->GetPositionCoordinate()->GetValue(pos);
}

//----------------------------------------------------------------------
void vtkResliceCursorRepresentation::GetWorldThicknessLabelPosition(double pos[3])
{
  double viewportPos[3], worldPos[4];
  pos[0] = pos[1] = pos[2] = 0.0;
  if (!this->Renderer)
  {
    vtkErrorMacro("GetWorldLabelPosition: no renderer!");
    return;
  }

  this->ThicknessTextActor->GetPositionCoordinate()->GetValue(viewportPos);
  this->Renderer->ViewportToNormalizedViewport(viewportPos[0], viewportPos[1]);
  this->Renderer->NormalizedViewportToView(viewportPos[0], viewportPos[1], viewportPos[2]);
  this->Renderer->SetViewPoint(viewportPos);
  this->Renderer->ViewToWorld();
  this->Renderer->GetWorldPoint(worldPos);

  if (worldPos[3] != 0.0)
  {
    pos[0] = worldPos[0]/worldPos[3];
    pos[1] = worldPos[1]/worldPos[3];
    pos[2] = worldPos[2]/worldPos[3];
  }
  else
  {
    vtkErrorMacro("GetWorldLabelPosition: world position at index 3 is 0, not dividing by 0");
  }
}

//----------------------------------------------------------------------
void vtkResliceCursorRepresentation::SetManipulationMode( int m )
{
  this->ManipulationMode = m;
}

//----------------------------------------------------------------------
void vtkResliceCursorRepresentation::BuildRepresentation()
{
  this->Reslice->SetInputData(this->GetResliceCursor()->GetImage());

  this->TexturePlaneActor->SetVisibility(
      this->GetResliceCursor()->GetImage() ?
        (this->ShowReslicedImage && !this->UseImageActor): 0);
  this->ImageActor->SetVisibility(
      this->GetResliceCursor()->GetImage() ?
        (this->ShowReslicedImage && this->UseImageActor) : 0);

  // Update the reslice plane if the plane is being manipulated
  if (this->GetManipulationMode() != WindowLevelling )
  {
    this->UpdateReslicePlane();
  }

  this->ImageActor->SetDisplayExtent(this->ColorMap->GetOutput()->GetExtent());

  // Update any text annotations
  this->ManageTextDisplay();
}

//----------------------------------------------------------------------------
void vtkResliceCursorRepresentation::InitializeReslicePlane()
{
  if ( !this->GetResliceCursor()->GetImage())
  {
    return;
  }

  // this->GetResliceCursor()->GetImage()->UpdateInformation();

  // Initialize the reslice plane origins. Offset should be zero within
  // this function here.

  this->ComputeReslicePlaneOrigin();

  // Finally reset the camera to whatever orientation they were staring in

  this->ResetCamera();
}

//----------------------------------------------------------------------------
void vtkResliceCursorRepresentation::ResetCamera()
{

  // Reset the camera back to the default and the focal point to where
  // the cursor center is

  if (this->Renderer)
  {
    double center[3], camPos[3], n[3];
    this->GetResliceCursor()->GetCenter(center);
    this->Renderer->GetActiveCamera()->SetFocalPoint(center);

    const int normalAxis = this->GetCursorAlgorithm()->GetReslicePlaneNormal();
    this->GetResliceCursor()->GetPlane(normalAxis)->GetNormal(n);
    vtkMath::Add( center, n, camPos );
    this->Renderer->GetActiveCamera()->SetPosition(camPos);

    // Reset the camera in response to changes.
    this->Renderer->ResetCamera();
    this->Renderer->ResetCameraClippingRange();
  }
}

//----------------------------------------------------------------------------
// This is the first axis of the reslice on the currently resliced plane
//
void vtkResliceCursorRepresentation::GetVector1(double v1[3])
{
  // From the initial view up vector, compute its cross product with the
  // current plane normal. This is Vector1. Then Vector2 is the cross product
  // of Vector1 and the normal.

  double v2[3];
  double* p2 = this->PlaneSource->GetPoint2();
  double* o =  this->PlaneSource->GetOrigin();

  // Vector p2 -> o
  vtkMath::Subtract( p2, o, v2 );

  const int planeOrientation =
    this->GetCursorAlgorithm()->GetReslicePlaneNormal();
  vtkPlane *plane = this->GetResliceCursor()->GetPlane(planeOrientation);

  double planeNormal[3];
  plane->GetNormal(planeNormal);

  vtkMath::Cross( v2, planeNormal, v1 );
  vtkMath::Normalize(v1);
}

//----------------------------------------------------------------------------
// This is the second axis of the reslice on the currently resliced plane
// It is orthogonal to v1 and to the plane normal. Note that this is not the
// same as the reslice cursor's axes, which need not be orthogonal to each
// other. The goal of vector1 and vector2 is to compute the X and Y axes of
// the resliced plane.
//
void vtkResliceCursorRepresentation::GetVector2(double v2[3])
{
  const int planeOrientation =
    this->GetCursorAlgorithm()->GetReslicePlaneNormal();
  vtkPlane *plane = this->GetResliceCursor()->GetPlane(planeOrientation);
  double planeNormal[3];
  plane->GetNormal(planeNormal);

  double v1[3];
  this->GetVector1(v1);

  vtkMath::Cross( planeNormal, v1, v2 );
  vtkMath::Normalize(v2);
}

//----------------------------------------------------------------------
// Compute the origin of the reslice plane prior to transformations.
//
void vtkResliceCursorRepresentation::ComputeReslicePlaneOrigin()
{
  double bounds[6];
  this->GetResliceCursor()->GetImage()->GetBounds(bounds);


  double center[3], imageCenter[3], offset[3];
  this->GetResliceCursor()->GetCenter(center);
  this->GetResliceCursor()->GetImage()->GetCenter(imageCenter);

  // Offset based on the center of the image and how far from it the
  // reslice cursor is. This allows us to capture the whole image even
  // if we resliced in awkward places.

  for (int i = 0; i < 3; i++)
  {
    offset[i] = -fabs(center[i] - imageCenter[i]);
  }

  // Now resize the plane based on these offsets.

  const int planeOrientation =
    this->GetCursorAlgorithm()->GetReslicePlaneNormal();

  // Now set the size of the plane based on the location of the cursor so as to
  // at least completely cover the viewed region

  if ( planeOrientation == 1 )
  {
    this->PlaneSource->SetOrigin(bounds[0]+offset[0],center[1],bounds[4]+offset[2]);
    this->PlaneSource->SetPoint1(bounds[1]-offset[0],center[1],bounds[4]+offset[2]);
    this->PlaneSource->SetPoint2(bounds[0]+offset[0],center[1],bounds[5]-offset[2]);
  }
  else if ( planeOrientation == 2 )
  {
    this->PlaneSource->SetOrigin(bounds[0]+offset[0],bounds[2]+offset[1],center[2]);
    this->PlaneSource->SetPoint1(bounds[1]-offset[0],bounds[2]+offset[1],center[2]);
    this->PlaneSource->SetPoint2(bounds[0]+offset[0],bounds[3]-offset[1],center[2]);
  }
  else if ( planeOrientation == 0 )
  {
    this->PlaneSource->SetOrigin(center[0],bounds[2]+offset[1],bounds[4]+offset[2]);
    this->PlaneSource->SetPoint1(center[0],bounds[3]-offset[1],bounds[4]+offset[2]);
    this->PlaneSource->SetPoint2(center[0],bounds[2]+offset[1],bounds[5]-offset[2]);
  }
}

//----------------------------------------------------------------------
void vtkResliceCursorRepresentation::UpdateReslicePlane()
{
  if ( !this->GetResliceCursor()->GetImage() ||
       !this->TexturePlaneActor->GetVisibility() )
  {
    return;
  }

  // Reinitialize the reslice plane.. We will recompute everything here.
  if (this->PlaneSource->GetPoint1()[0] == 0.5 &&
      this->PlaneSource->GetOrigin()[0] == -0.5)
  {
    this->InitializeReslicePlane();
  }

  // Calculate appropriate pixel spacing for the reslicing
  //
  // this->GetResliceCursor()->UpdateInformation();
  double spacing[3];
  this->GetResliceCursor()->GetImage()->GetSpacing(spacing);
  double origin[3];
  this->GetResliceCursor()->GetImage()->GetOrigin(origin);
  int extent[6];
  this->GetResliceCursor()->GetImage()->GetExtent(extent);

  for (int i = 0; i < 3; i++)
  {
    if (extent[2*i] > extent[2*i + 1])
    {
      vtkErrorMacro("Invalid extent ["
                    << extent[0] << ", " << extent[1] << ", "
                    << extent[2] << ", " << extent[3] << ", "
                    << extent[4] << ", " << extent[5] << "]."
                    << " Perhaps the input data is empty?");
      break;
    }
  }

  const int planeOrientation =
    this->GetCursorAlgorithm()->GetReslicePlaneNormal();
  vtkPlane *plane = this->GetResliceCursor()->GetPlane(planeOrientation);
  double planeNormal[3];
  plane->GetNormal(planeNormal);


  // Compute the origin of the reslice plane prior to transformations.

  this->ComputeReslicePlaneOrigin();

  this->PlaneSource->SetNormal(planeNormal);
  this->PlaneSource->SetCenter(plane->GetOrigin());


  double planeAxis1[3];
  double planeAxis2[3];


  double* p1 = this->PlaneSource->GetPoint1();
  double* o =  this->PlaneSource->GetOrigin();
  vtkMath::Subtract( p1, o, planeAxis1 );
  double* p2 = this->PlaneSource->GetPoint2();
  vtkMath::Subtract( p2, o, planeAxis2 );

  // The x,y dimensions of the plane
  //
  const double planeSizeX = vtkMath::Normalize(planeAxis1);
  const double planeSizeY = vtkMath::Normalize(planeAxis2);

  double normal[3];
  this->PlaneSource->GetNormal(normal);

  this->NewResliceAxes->Identity();
  for ( int i = 0; i < 3; i++ )
  {
     this->NewResliceAxes->SetElement(0,i,planeAxis1[i]);
     this->NewResliceAxes->SetElement(1,i,planeAxis2[i]);
     this->NewResliceAxes->SetElement(2,i,normal[i]);
  }

  const double spacingX = fabs(planeAxis1[0]*spacing[0])+
                          fabs(planeAxis1[1]*spacing[1])+
                          fabs(planeAxis1[2]*spacing[2]);

  const double spacingY = fabs(planeAxis2[0]*spacing[0])+
                          fabs(planeAxis2[1]*spacing[1])+
                          fabs(planeAxis2[2]*spacing[2]);

  double planeOrigin[4];
  this->PlaneSource->GetOrigin(planeOrigin);

  planeOrigin[3] = 1.0;
  double originXYZW[4];
  double neworiginXYZW[4];

  this->NewResliceAxes->MultiplyPoint(planeOrigin, originXYZW);
  this->NewResliceAxes->Transpose();
  this->NewResliceAxes->MultiplyPoint(originXYZW, neworiginXYZW);

  this->NewResliceAxes->SetElement(0,3,neworiginXYZW[0]);
  this->NewResliceAxes->SetElement(1,3,neworiginXYZW[1]);
  this->NewResliceAxes->SetElement(2,3,neworiginXYZW[2]);


  // Compute a new set of resliced extents
  int extentX, extentY;

  // Pad extent up to a power of two for efficient texture mapping

  // make sure we're working with valid values
  double realExtentX = ( spacingX == 0 ) ? VTK_INT_MAX : planeSizeX / spacingX;


  // Sanity check the input data:
  // * if realExtentX is too large, extentX will wrap
  // * if spacingX is 0, things will blow up.
  if (realExtentX > (VTK_INT_MAX >> 1))
  {
    vtkErrorMacro(<<"Invalid X extent: " << realExtentX);
    extentX = 0;
  }
  else
  {
    extentX = 1;
    while (extentX < realExtentX)
    {
      extentX = extentX << 1;
    }
  }

  // make sure extentY doesn't wrap during padding
  double realExtentY = ( spacingY == 0 ) ? VTK_INT_MAX : planeSizeY / spacingY;

  if (realExtentY > (VTK_INT_MAX >> 1))
  {
    vtkErrorMacro(<<"Invalid Y extent: " << realExtentY);
    extentY = 0;
  }
  else
  {
    extentY = 1;
    while (extentY < realExtentY)
    {
      extentY = extentY << 1;
    }
  }

  double outputSpacingX = (extentX == 0) ? 1.0 : planeSizeX/extentX;
  double outputSpacingY = (extentY == 0) ? 1.0 : planeSizeY/extentY;

  bool modify = false;
  for (int i = 0; i < 4; i++)
  {
    for (int j = 0; j < 4; j++)
    {
      double d = this->NewResliceAxes->GetElement(i,j);
      if (d != this->ResliceAxes->GetElement(i,j))
      {
        this->ResliceAxes->SetElement(i,j,d);
        modify = true;
      }
    }
  }

  if (modify)
  {
    this->ResliceAxes->Modified();
  }

  this->SetResliceParameters( outputSpacingX, outputSpacingY,
      extentX, extentY );
}

//----------------------------------------------------------------------------
void vtkResliceCursorRepresentation::ComputeOrigin(vtkMatrix4x4 *m)
{
  double center[4] = {0,0,0,1};
  double centerTransformed[4];

  this->GetResliceCursor()->GetCenter(center);
  m->MultiplyPoint(center, centerTransformed);

  for (int i = 0; i < 3; i++)
  {
    m->SetElement(i, 3,
        m->GetElement(i,3) + center[i] - centerTransformed[i]);
  }
}

//----------------------------------------------------------------------------
void vtkResliceCursorRepresentation
::SetResliceParameters( double outputSpacingX, double outputSpacingY,
    int extentX, int extentY )
{
  vtkImageReslice *reslice = vtkImageReslice::SafeDownCast(this->Reslice);

  if (reslice)
  {
    // Set the default color the minimum scalar value
    double range[2];
    vtkImageData::SafeDownCast(reslice->GetInput())->
      GetScalarRange( range );
    reslice->SetBackgroundLevel(range[0]);

    this->ColorMap->SetInputConnection(reslice->GetOutputPort());
    reslice->TransformInputSamplingOff();
    reslice->AutoCropOutputOn();
    reslice->SetResliceAxes(this->ResliceAxes);
    reslice->SetOutputSpacing(outputSpacingX, outputSpacingY, 1);
    reslice->SetOutputOrigin(0.5*outputSpacingX, 0.5*outputSpacingY, 0);
    reslice->SetOutputExtent(0, extentX-1, 0, extentY-1, 0, 0);
  }
}

//----------------------------------------------------------------------------
void vtkResliceCursorRepresentation
::SetWindowLevel(double window, double level, int copy)
{
  if ( copy )
  {
    this->CurrentWindow = window;
    this->CurrentLevel = level;
    return;
  }

  if ( this->CurrentWindow == window && this->CurrentLevel == level )
  {
    return;
  }

  // if the new window is negative and the old window was positive invert table
  if ( (( window < 0 && this->CurrentWindow > 0 ) ||
        ( window > 0 && this->CurrentWindow < 0 )) )
  {
    this->InvertTable();
  }

  this->CurrentWindow = window;
  this->CurrentLevel = level;

  double rmin = this->CurrentLevel - 0.5*fabs( this->CurrentWindow );
  double rmax = rmin + fabs( this->CurrentWindow );
  this->LookupTable->SetRange( rmin, rmax );

  this->Modified();
}

//----------------------------------------------------------------------------
void vtkResliceCursorRepresentation::GetWindowLevel(double wl[2])
{
  wl[0] = this->CurrentWindow;
  wl[1] = this->CurrentLevel;
}

//----------------------------------------------------------------------------
void vtkResliceCursorRepresentation::WindowLevel(double X, double Y)
{
  if ( !this->Renderer )
  {
    return;
  }

  int *size = this->Renderer->GetSize();
  double window = this->InitialWindow;
  double level = this->InitialLevel;

  // Compute normalized delta

  double dx = 2.0 * ( X - this->StartEventPosition[0] ) / size[0];
  double dy = 2.0 * ( this->StartEventPosition[1] - Y ) / size[1];

  // Scale by current values

  if ( fabs( window ) > 0.01 )
  {
    dx = dx * window;
  }
  else
  {
    dx = dx * ( window < 0 ? -0.01 : 0.01 );
  }
  if ( fabs( level ) > 0.01 )
  {
    dy = dy * level;
  }
  else
  {
    dy = dy * ( level < 0 ? -0.01 : 0.01 );
  }

  // Abs so that direction does not flip

  if ( window < 0.0 )
  {
    dx = -1 * dx;
  }
  if ( level < 0.0 )
  {
    dy = -1 * dy;
  }

  // Compute new window level

  double newWindow = dx + window;
  double newLevel = level - dy;

  if ( fabs( newWindow ) < 0.01 )
  {
    newWindow = 0.01 * ( newWindow < 0 ? -1 : 1 );
  }
  if ( fabs( newLevel ) < 0.01 )
  {
    newLevel = 0.01 * ( newLevel < 0 ? -1 : 1 );
  }

  if (( newWindow < 0 && this->CurrentWindow > 0 ) ||
      ( newWindow > 0 && this->CurrentWindow < 0 ))
  {
    this->InvertTable();
  }

  double rmin = newLevel - 0.5*fabs( newWindow );
  double rmax = rmin + fabs( newWindow );
  this->LookupTable->SetRange( rmin, rmax );

  if (this->DisplayText && (this->CurrentWindow != newWindow ||
        this->CurrentLevel != newLevel) )
  {
    this->CurrentWindow = newWindow;
    this->CurrentLevel = newLevel;
  }
}

//----------------------------------------------------------------------------
void vtkResliceCursorRepresentation::InvertTable()
{
  vtkLookupTable *lut = vtkLookupTable::SafeDownCast(this->LookupTable);

  if ( lut )
  {
    int index = lut->GetNumberOfTableValues();
    unsigned char swap[4];
    size_t num = 4*sizeof(unsigned char);
    vtkUnsignedCharArray* table = lut->GetTable();
    for ( int count = 0; count < --index; count++ )
    {
      unsigned char *rgba1 = table->GetPointer(4*count);
      unsigned char *rgba2 = table->GetPointer(4*index);
      memcpy( swap,  rgba1, num );
      memcpy( rgba1, rgba2, num );
      memcpy( rgba2, swap,  num );
    }

    // force the lookuptable to update its InsertTime to avoid
    // rebuilding the array
    lut->SetTableValue( 0, lut->GetTableValue( 0 ) );
  }
}

//----------------------------------------------------------------------------
void vtkResliceCursorRepresentation::CreateDefaultResliceAlgorithm()
{
  // Allows users to optionally use their own reslice filters or other
  // algorithms here.
  if (!this->Reslice)
  {
    this->Reslice = vtkImageReslice::New();
  }
}

//----------------------------------------------------------------------------
vtkScalarsToColors* vtkResliceCursorRepresentation::CreateDefaultLookupTable()
{
  vtkLookupTable* lut = vtkLookupTable::New();
  lut->Register(this);
  lut->Delete();
  lut->SetNumberOfColors( 256);
  lut->SetHueRange( 0, 0);
  lut->SetSaturationRange( 0, 0);
  lut->SetValueRange( 0 ,1);
  lut->SetAlphaRange( 1, 1);
  lut->Build();
  return lut;
}

//----------------------------------------------------------------------------
void vtkResliceCursorRepresentation::ActivateText(int i)
{
  this->TextActor->SetVisibility(this->Renderer &&
        this->GetVisibility() && i && this->DisplayText );
}

//----------------------------------------------------------------------------
void vtkResliceCursorRepresentation::ManageTextDisplay()
{
  if ( !this->DisplayText )
  {
    return;
  }

  if ( this->ManipulationMode ==
       vtkResliceCursorRepresentation::WindowLevelling )
  {
    sprintf(this->TextBuff,"Window, Level: ( %g, %g )",
            this->CurrentWindow, this->CurrentLevel );
  }
  else if (this->ManipulationMode ==
      vtkResliceCursorRepresentation::ResizeThickness )
  {
    // For now all the thickness' are the same anyway.
    sprintf(this->TextBuff,"Reslice Thickness: %g mm",
            this->GetResliceCursor()->GetThickness()[0] );
  }

  this->TextActor->SetInput(this->TextBuff);
  this->TextActor->Modified();
}

//----------------------------------------------------------------------------
void vtkResliceCursorRepresentation::SetTextProperty(vtkTextProperty* tprop)
{
  this->TextActor->SetTextProperty(tprop);
}

//----------------------------------------------------------------------------
vtkTextProperty* vtkResliceCursorRepresentation::GetTextProperty()
{
  return this->TextActor->GetTextProperty();
}

//----------------------------------------------------------------------------
void vtkResliceCursorRepresentation::GenerateText()
{
  sprintf(this->TextBuff,"NA");
  this->TextActor->SetInput(this->TextBuff);
  this->TextActor->SetTextScaleModeToNone();

  vtkTextProperty* textprop = this->TextActor->GetTextProperty();
  textprop->SetColor(1,1,1);
  textprop->SetFontFamilyToArial();
  textprop->SetFontSize(18);
  textprop->BoldOff();
  textprop->ItalicOff();
  textprop->ShadowOff();
  textprop->SetJustificationToLeft();
  textprop->SetVerticalJustificationToBottom();

  vtkCoordinate* coord = this->TextActor->GetPositionCoordinate();
  coord->SetCoordinateSystemToNormalizedViewport();
  coord->SetValue(.01, .01);

  this->TextActor->VisibilityOff();
}

//----------------------------------------------------------------------
// Prints an object if it exists.
#define vtkPrintMemberObjectMacro( obj, os, indent ) \
  os << indent << #obj << ": "; \
  if (this->obj) \
  { \
    os << this->obj << "\n"; \
  } \
  else \
  { \
    os << "(null)\n"; \
  }

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

  os << indent << "Tolerance: " << this->Tolerance << "\n";
  os << indent << "Thickness Label Text: " << this->GetThicknessLabelText() << "\n";
  os << indent << "PlaneSource: " << this->PlaneSource << "\n";
  if (this->PlaneSource)
  {
    this->PlaneSource->PrintSelf(os,indent.GetNextIndent());
  }
  os << indent << "PlaneSource: " << this->PlaneSource << "\n";
  vtkPrintMemberObjectMacro( ThicknessLabelFormat, os, indent );
  vtkPrintMemberObjectMacro( Reslice, os, indent );
  vtkPrintMemberObjectMacro( ThicknessTextProperty, os, indent );
  vtkPrintMemberObjectMacro( ThicknessTextMapper, os, indent );
  vtkPrintMemberObjectMacro( ThicknessTextActor, os, indent );
  vtkPrintMemberObjectMacro( ResliceAxes, os, indent );
  vtkPrintMemberObjectMacro( NewResliceAxes, os, indent );
  vtkPrintMemberObjectMacro( ColorMap, os, indent );
  vtkPrintMemberObjectMacro( TexturePlaneActor, os, indent );
  vtkPrintMemberObjectMacro( Texture, os, indent );
  vtkPrintMemberObjectMacro( LookupTable, os, indent );
  vtkPrintMemberObjectMacro( ImageActor, os, indent );
  vtkPrintMemberObjectMacro( TextActor, os, indent );
  os << indent << "RestrictPlaneToVolume: "
     << this->RestrictPlaneToVolume << "\n";
  os << indent << "ShowReslicedImage: "
     << this->ShowReslicedImage << "\n";
  os << indent << "OriginalWindow: "
     << this->OriginalWindow << "\n";
  os << indent << "OriginalLevel: "
     << this->OriginalLevel << "\n";
  os << indent << "CurrentWindow: "
     << this->CurrentWindow << "\n";
  os << indent << "CurrentLevel: "
     << this->CurrentLevel << "\n";
  os << indent << "InitialWindow: "
     << this->InitialWindow << "\n";
  os << indent << "InitialLevel: "
     << this->InitialLevel << "\n";
  os << indent << "UseImageActor: "
     << this->UseImageActor << "\n";
  os << indent << "DisplayText: "
     << this->DisplayText << "\n";
  // this->ManipulationMode
  // this->LastEventPosition[2]
  // this->TextBuff[128];
  // this->ResliceAxes;
  // this->LookupTable;
  // this->Reslice;
  // this->ThicknessLabelFormat;
  // this->ColorMap;
  // this->ImageActor;
  // this->ThicknessTextProperty;
  // this->ThicknessTextMapper;
  // this->ThicknessTextActor;
  // this->NewResliceAxes;
  // this->TexturePlaneActor;
  // this->Texture;
  // this->TextActor;
}