ITK/Examples/ItkVtkGlue/itkImageToVTKImageFilter

Many of the ITK examples use VTK to display the results. The files on this page provide a simple interface between ITK and VTK.

NOTE: If you download the entire ITK Wiki Examples Collection,, the ItkVtkGlue directory will be included. If you wish to just build a few examples, then you will need to download ItkVtkGlue and build it.

itkImageToVTKImageFilter.h

<source lang=cpp> /*=========================================================================

*
*  Copyright Insight Software Consortium
*
*  Licensed under the Apache License, Version 2.0 (the "License");
*  you may not use this file except in compliance with the License.
*  You may obtain a copy of the License at
*
*         http://www.apache.org/licenses/LICENSE-2.0.txt
*
*  Unless required by applicable law or agreed to in writing, software
*  distributed under the License is distributed on an "AS IS" BASIS,
*  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
*  See the License for the specific language governing permissions and
*  limitations under the License.
*
*=========================================================================*/

1. ifndef __itkImageToVTKImageFilter_h
2. define __itkImageToVTKImageFilter_h

1. include "itkVTKImageExport.h"
2. include "vtkImageImport.h"
3. include "vtkImageData.h"

namespace itk {

/** \class ImageToVTKImageFilter

* \brief Converts an ITK image into a VTK image and plugs a
*  itk data pipeline to a VTK datapipeline.
*
*  This class puts together an itkVTKImageExporter and a vtkImageImporter.
*  It takes care of the details related to the connection of ITK and VTK
*  pipelines. The User will perceive this filter as an adaptor to which
*  an itk::Image can be plugged as input and a vtkImage is produced as
*  output.
*
* \ingroup   ImageFilters
*/

template <class TInputImage > class ImageToVTKImageFilter : public ProcessObject { public:

 /** Standard class typedefs. */
 typedef ImageToVTKImageFilter       Self;
 typedef ProcessObject             Superclass;
 typedef SmartPointer<Self>        Pointer;
 typedef SmartPointer<const Self>  ConstPointer;

 /** Method for creation through the object factory. */
 itkNewMacro(Self);

 /** Run-time type information (and related methods). */
 itkTypeMacro(ImageToVTKImageFilter, ProcessObject);

 /** Some typedefs. */
 typedef TInputImage InputImageType;
 typedef typename InputImageType::ConstPointer  InputImagePointer;

 typedef VTKImageExport< InputImageType>        ExporterFilterType;
 typedef typename ExporterFilterType::Pointer   ExporterFilterPointer;

 /** Get the output in the form of a vtkImage.
     This call is delegated to the internal vtkImageImporter filter  */
 vtkImageData *  GetOutput() const;

 /** Set the input in the form of an itk::Image */
 using Superclass::SetInput;
 void SetInput( const InputImageType * );

 /** Return the internal VTK image importer filter.
     This is intended to facilitate users the access
     to methods in the importer */
 vtkImageImport * GetImporter() const;

 /** Return the internal ITK image exporter filter.
     This is intended to facilitate users the access
     to methods in the exporter */
 ExporterFilterType * GetExporter() const;

 /** This call delegate the update to the importer */
 void Update();

protected:

 ImageToVTKImageFilter();
 virtual ~ImageToVTKImageFilter();

private:

 ImageToVTKImageFilter(const Self&); //purposely not implemented
 void operator=(const Self&); //purposely not implemented

 ExporterFilterPointer       m_Exporter;
 vtkImageImport *            m_Importer;

};

} // end namespace itk

1. ifndef ITK_MANUAL_INSTANTIATION
2. include "itkImageToVTKImageFilter.txx"
3. endif

1. endif

</source>

itkImageToVTKImageFilter.txx

<source lang=cpp> /*=========================================================================

*
*  Copyright Insight Software Consortium
*
*  Licensed under the Apache License, Version 2.0 (the "License");
*  you may not use this file except in compliance with the License.
*  You may obtain a copy of the License at
*
*         http://www.apache.org/licenses/LICENSE-2.0.txt
*
*  Unless required by applicable law or agreed to in writing, software
*  distributed under the License is distributed on an "AS IS" BASIS,
*  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
*  See the License for the specific language governing permissions and
*  limitations under the License.
*
*=========================================================================*/

1. ifndef _itkImageToVTKImageFilter_txx
2. define _itkImageToVTKImageFilter_txx

1. include "itkImageToVTKImageFilter.h"

namespace itk {

/**

* Constructor
*/

template <class TInputImage> ImageToVTKImageFilter<TInputImage>

ImageToVTKImageFilter()

{

 m_Importer = vtkImageImport::New();
 m_Exporter = ExporterFilterType::New();

 m_Importer->SetUpdateInformationCallback(m_Exporter->GetUpdateInformationCallback());
 m_Importer->SetPipelineModifiedCallback(m_Exporter->GetPipelineModifiedCallback());
 m_Importer->SetWholeExtentCallback(m_Exporter->GetWholeExtentCallback());
 m_Importer->SetSpacingCallback(m_Exporter->GetSpacingCallback());
 m_Importer->SetOriginCallback(m_Exporter->GetOriginCallback());
 m_Importer->SetScalarTypeCallback(m_Exporter->GetScalarTypeCallback());
 m_Importer->SetNumberOfComponentsCallback(m_Exporter->GetNumberOfComponentsCallback());
 m_Importer->SetPropagateUpdateExtentCallback(m_Exporter->GetPropagateUpdateExtentCallback());
 m_Importer->SetUpdateDataCallback(m_Exporter->GetUpdateDataCallback());
 m_Importer->SetDataExtentCallback(m_Exporter->GetDataExtentCallback());
 m_Importer->SetBufferPointerCallback(m_Exporter->GetBufferPointerCallback());
 m_Importer->SetCallbackUserData(m_Exporter->GetCallbackUserData());

}

/**

* Destructor
*/

template <class TInputImage> ImageToVTKImageFilter<TInputImage>

~ImageToVTKImageFilter()

{

 if( m_Importer )
   {
   m_Importer->Delete();
   m_Importer = 0;
   }

}

/**

* Set an itk::Image as input
*/

template <class TInputImage> void ImageToVTKImageFilter<TInputImage>

SetInput( const InputImageType * inputImage )

{

 m_Exporter->SetInput( inputImage );

}

/**

* Get a vtkImage as output
*/

template <class TInputImage> vtkImageData * ImageToVTKImageFilter<TInputImage>

GetOutput() const

{

 return m_Importer->GetOutput();

}

/**

* Get the importer filter
*/

template <class TInputImage> vtkImageImport * ImageToVTKImageFilter<TInputImage>

GetImporter() const

{

 return m_Importer;

}

/**

* Get the exporter filter
*/

template <class TInputImage> typename ImageToVTKImageFilter<TInputImage>::ExporterFilterType * ImageToVTKImageFilter<TInputImage>

GetExporter() const

{

 return m_Exporter.GetPointer();

}

/**

* Delegate the Update to the importer
*/

template <class TInputImage> void ImageToVTKImageFilter<TInputImage>

Update()

{

 m_Importer->Update();

} } // end namespace itk

1. endif

</source>

QuickView.h

<source lang="cpp"> /*=========================================================================

*
*  Copyright Insight Software Consortium
*
*  Licensed under the Apache License, Version 2.0 (the "License");
*  you may not use this file except in compliance with the License.
*  You may obtain a copy of the License at
*
*         http://www.apache.org/licenses/LICENSE-2.0.txt
*
*  Unless required by applicable law or agreed to in writing, software
*  distributed under the License is distributed on an "AS IS" BASIS,
*  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
*  See the License for the specific language governing permissions and
*  limitations under the License.
*
*=========================================================================*/

1. ifndef QuickView_h
2. define QuickView_h

1. include <vector>
2. include <algorithm>
3. include <string>

1. include <itkImage.h>
2. include <itkRGBPixel.h>
3. include <itkIntTypes.h>

/** \class ImageInfo

* \brief A container for an image and its descriptiom
* \ingroup ITKVtkGlue
*/

class ImageInfo { public:

 typedef itk::Image<unsigned char, 2> ImageType;

 ImageInfo(ImageType *image, std::string description="")
 {
   m_Image = image;
   m_Description = description;
 }

 ImageType::Pointer m_Image;
 std::string        m_Description;

};

/** \class RGBImageInfo

* \brief A container for an rgb image and its descriptiom
* \ingroup ITKVtkGlue
*/

class RGBImageInfo { public:

 typedef itk::Image<itk::RGBPixel<unsigned char>, 2> ImageType;
 RGBImageInfo(ImageType *image, std::string description="")
 {
   m_Image = image;
   m_Description = description;
 }

 ImageType::Pointer m_Image;
 std::string        m_Description;

};

/** \class QuickView

* \brief A convenient class to render itk images with vtk
*
* This class presents a convenient and efficient mechanism to display
* ITK images in VTK render windows.
*
* The AddImage and AddRGBImage methods collect ITK images to be
* rendered in a collection of VTK RenderWindow's. Each image can
* be flipped about the vertical axis. An optional description will be
* displayed at the bottom of each render window.
*
* If m_ShareCamera is true, a single <a href="http://www.vtk.org/doc/nightly/html/classvtkCamera.html">vtkCamera</a>
* will be used for each render window (default is false).
*
* Each image is rescaled to have a range between 0 and 255. Currently, the size
* of each render window is fixed at 300,300 and the text size for descriptions
* is fixed at 10.
*
* The Visualize method displays the render windows and starts a
* <a href="http://www.vtk.org/doc/nightly/html/classvtkInteractorStyleImage.html">vtkInteractorStyleImage</a>.
* The layout and background color of each render window is fixed. The optional
* boolean for the constructor, if false, bypasses the interactor. This is useful
* for running tests.
*
* Typical usage:
*
* \code
*  QuickView viewer;
*  viewer.AddImage(someFilter->GetOutput().
*                  true (to flip image) or false.
*                  "text to display with the image");
*
*  viewer.AddRGBImage(someFilter->GetOutput().
*                     true (to flip image) or false.
*                     "text to display with the image");
*  \endcode
*
* \ingroup ITKVtkGlue
*/

class QuickView { public:

 QuickView()
 {
   m_ShareCamera = true;
   m_Interpolate = true;
   m_Counter = 0;
   m_Snapshot = false;
   m_SnapshotPath = "";
   m_SnapshotPrefix = "snapshot_";
   m_SnapshotExtension = "png";
   m_NumberOfColumns = 4;
   m_ViewPortSize = 300;
 }
 /** Add an image to be rendered. */
 template<typename TImage> void AddImage(
   TImage *,
   bool FlipVertical=true,
   std::string Description="");

 /** Add an RGB image to be rendered */
 template<typename TImage> void AddRGBImage(
   TImage *,
   bool FlipVertical=true,
   std::string Description="");

 /** Render the images. If interact is tru, start a vtk
  * Interactor. If false, return after one render.
  */
 void Visualize(bool interact=true);

 /** Each render window will have its own camera */
 void ShareCameraOff()
 {
   m_ShareCamera = false;
 }

 /** Each render window will use the same camera */
 void ShareCameraOn()
 {
   m_ShareCamera = true;
 }

 /** Use pixel replication in rendered image */
 void InterpolateOff()
 {
   m_Interpolate = false;
 }

 /** Use pixel interpolation in rendered image */
 void InterpolateOn()
 {
   m_Interpolate = true;
 }

 /** Each render window will take a snaphot */
 void SnapshotOn()
 {
   m_Snapshot = true;
 }

 /** Each render window will take a snaphot */
 void SnapshotOff()
 {
   m_Snapshot = false;
 }

 void SetSnapshotPath( const std::string& iPath )
 {
   m_SnapshotPath = iPath;
 }

 void SetSnapshotPrefix( const std::string& iPrefix )
 {
   m_SnapshotPrefix = iPrefix;
 }

 /** Provide the image format to be used when taking snapshot */
 void SetSnapshotExtension( const std::string& iExtension )
 {
   m_SnapshotExtension = iExtension;
   std::transform(
         m_SnapshotExtension.begin(),
         m_SnapshotExtension.end(),
         m_SnapshotExtension.begin(),
         ::tolower );
 }

 /** Set the number of columns, default 4.*/
 void SetNumberOfColumns (const unsigned int columns)
 {
   m_NumberOfColumns = columns;
 }

 /** Set the viewport size, default 300.*/
 void SetViewPortSize (const unsigned int size)
 {
   m_ViewPortSize = size;
 }

private:

 std::vector<ImageInfo>    Images;        // Container for images
 std::vector<RGBImageInfo> RGBImages;     // Container for rgb images
 itk::IdentifierType       m_Counter;
 std::string               m_SnapshotPath;
 std::string               m_SnapshotPrefix;
 std::string               m_SnapshotExtension;
 bool                      m_ShareCamera;
 bool                      m_Snapshot;
 bool                      m_Interpolate;
 unsigned int              m_NumberOfColumns;
 unsigned int              m_ViewPortSize;

};

1. endif

</source>

QuickView.cxx

<source lang="cpp"> /*=========================================================================

*
*  Copyright Insight Software Consortium
*
*  Licensed under the Apache License, Version 2.0 (the "License");
*  you may not use this file except in compliance with the License.
*  You may obtain a copy of the License at
*
*         http://www.apache.org/licenses/LICENSE-2.0.txt
*
*  Unless required by applicable law or agreed to in writing, software
*  distributed under the License is distributed on an "AS IS" BASIS,
*  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
*  See the License for the specific language governing permissions and
*  limitations under the License.
*
*=========================================================================*/

1. include "QuickView.h"

1. include "itkRescaleIntensityImageFilter.h"
2. include "itkVectorRescaleIntensityImageFilter.h"
3. include "itkRGBToVectorImageAdaptor.h"
4. include "itkFlipImageFilter.h"

1. include "vtkVersion.h"

1. include "vtkRenderWindowInteractor.h"
2. include "vtkImageMapper3D.h"
3. include "vtkImageActor.h"
4. include "vtkActor2D.h"
5. include "vtkInteractorStyleImage.h"
6. include "vtkRenderer.h"
7. include "vtkCamera.h"
8. include "vtkTextProperty.h"
9. include "vtkTextMapper.h"

1. include "vtkCaptureScreen.h"
2. include "vtkPNGWriter.h"
3. include "vtkJPEGWriter.h"
4. include "vtkBMPWriter.h"
5. include "vtkTIFFWriter.h"

1. include "itkImageToVTKImageFilter.h"

typedef itk::Image<itk::RGBPixel<unsigned char>, 2> UnsignedCharRGBImageType; typedef itk::Image<itk::RGBPixel<float>, 2> FloatRGBImageType;

typedef itk::Image<unsigned char, 2> UnsignedCharImageType; typedef itk::Image<char, 2> CharImageType; typedef itk::Image<unsigned short, 2> UnsignedShortImageType; typedef itk::Image<short, 2> ShortImageType; typedef itk::Image<unsigned int, 2> UnsignedIntImageType; typedef itk::Image<int, 2> IntImageType; typedef itk::Image<unsigned long, 2> UnsignedLongImageType; typedef itk::Image<long, 2> LongImageType; typedef itk::Image<float, 2> FloatImageType; typedef itk::Image<double, 2> DoubleImageType;

template void QuickView::AddImage<CharImageType>(

 CharImageType *image,
 bool FlipVertical,
 std::string Description);

template void QuickView::AddImage<UnsignedShortImageType>(

 UnsignedShortImageType *image,
 bool FlipVertical,
 std::string Description);

template void QuickView::AddImage<ShortImageType>(

 ShortImageType *image,
 bool FlipVertical,
 std::string Description);

template void QuickView::AddImage<UnsignedIntImageType>(

 UnsignedIntImageType *image,
 bool FlipVertical,
 std::string Description);

template void QuickView::AddImage<IntImageType>(

 IntImageType *image,
 bool FlipVertical,
 std::string Description);

template void QuickView::AddImage<UnsignedLongImageType>(

 UnsignedLongImageType *image,
 bool FlipVertical,
 std::string Description);

template void QuickView::AddImage<LongImageType>(

 LongImageType *image,
 bool FlipVertical,
 std::string Description);

template void QuickView::AddImage<FloatImageType>(

 FloatImageType *image,
 bool FlipVertical,
 std::string Description);

template void QuickView::AddImage<DoubleImageType>(

 DoubleImageType *image,
 bool FlipVertical,
 std::string Description);

template< > void QuickView::AddImage<UnsignedCharImageType>(

 UnsignedCharImageType *image,
 bool FlipVertical,
 std::string Description)

{

 if (FlipVertical)
   {
   typedef itk::FlipImageFilter< UnsignedCharImageType> FlipFilterType;
   FlipFilterType::Pointer flipper = FlipFilterType::New();
   bool flipAxes[3] = { false, true, false };
   flipper = FlipFilterType::New();
   flipper->SetFlipAxes(flipAxes);
   flipper->SetInput(image);
   flipper->Update();
   ImageInfo myImage(flipper->GetOutput(), Description);
   this->Images.push_back(myImage);
   }
 else
   {
   ImageInfo myImage(image, Description);
   this->Images.push_back(myImage);
   }

}

template<typename TImage> void QuickView::AddImage(

 TImage *image,
 bool FlipVertical,
 std::string Description)

{

 typedef itk::RescaleIntensityImageFilter<TImage, UnsignedCharImageType >
   rescaleFilterType;

 typename rescaleFilterType::Pointer rescaler = rescaleFilterType::New();
 rescaler->SetOutputMinimum(0);
 rescaler->SetOutputMaximum(255);
 rescaler->SetInput(image);
 rescaler->Update();

 this->AddImage(rescaler->GetOutput(), FlipVertical, Description);

}

template< > void QuickView::AddImage<UnsignedCharRGBImageType>(

 UnsignedCharRGBImageType *image,
 bool FlipVertical,
 std::string Description)

{

 if (FlipVertical)
   {
   typedef itk::FlipImageFilter< UnsignedCharRGBImageType> FlipFilterType;
   FlipFilterType::Pointer flipper = FlipFilterType::New();
   bool flipAxes[3] = { false, true, false };
   flipper = FlipFilterType::New();
   flipper->SetFlipAxes(flipAxes);
   flipper->SetInput(image);
   flipper->Update();
   RGBImageInfo myImage(flipper->GetOutput(), Description);
   this->RGBImages.push_back(myImage);
   }
 else
   {
   RGBImageInfo myImage(image, Description);
   this->RGBImages.push_back(myImage);
   }

}

template< > void QuickView::AddRGBImage<UnsignedCharRGBImageType>(

 UnsignedCharRGBImageType *image,
 bool FlipVertical,
 std::string Description)

{

 if (FlipVertical)
   {
   typedef itk::FlipImageFilter< UnsignedCharRGBImageType> FlipFilterType;
   FlipFilterType::Pointer flipper = FlipFilterType::New();
   bool flipAxes[3] = { false, true, false };
   flipper = FlipFilterType::New();
   flipper->SetFlipAxes(flipAxes);
   flipper->SetInput(image);
   flipper->Update();
   RGBImageInfo myImage(flipper->GetOutput(), Description);
   this->RGBImages.push_back(myImage);
   }
 else
   {
   RGBImageInfo myImage(image, Description);
   this->RGBImages.push_back(myImage);
   }

}

template< > void QuickView::AddRGBImage<FloatRGBImageType>(

 FloatRGBImageType *image,
 bool FlipVertical,
 std::string Description)

{

 typedef itk::RGBToVectorImageAdaptor<FloatRGBImageType> AdaptorType;
 AdaptorType::Pointer adaptor = AdaptorType::New();
 adaptor->SetImage(image);

 typedef itk::VectorRescaleIntensityImageFilter<AdaptorType, UnsignedCharRGBImageType > rescaleFilterType;
 rescaleFilterType::Pointer rescaler = rescaleFilterType::New();
 rescaler->SetOutputMaximumMagnitude(255);
 rescaler->SetInput(adaptor);
 rescaler->Update();
 this->AddRGBImage(rescaler->GetOutput(), FlipVertical, Description);

}

template< > void QuickView::AddImage<FloatRGBImageType>(

 FloatRGBImageType *image,
 bool FlipVertical,
 std::string Description)

{

 typedef itk::RGBToVectorImageAdaptor<FloatRGBImageType> AdaptorType;
 AdaptorType::Pointer adaptor = AdaptorType::New();
 adaptor->SetImage(image);

 typedef itk::VectorRescaleIntensityImageFilter<AdaptorType, UnsignedCharRGBImageType > rescaleFilterType;
 rescaleFilterType::Pointer rescaler = rescaleFilterType::New();
 rescaler->SetOutputMaximumMagnitude(255);
 rescaler->SetInput(adaptor);
 rescaler->Update();
 this->AddRGBImage(rescaler->GetOutput(), FlipVertical, Description);

}

void QuickView::Visualize(bool interact) {

 unsigned int rendererSize = this->m_ViewPortSize;
 unsigned int numberOfImages = this->Images.size() + this->RGBImages.size();
 unsigned int numberOfRows = (numberOfImages - 1) / this->m_NumberOfColumns + 1;
 unsigned int numberOfColumns = numberOfImages / (numberOfRows) + 1;
 if (numberOfColumns > numberOfImages)
   {
   numberOfColumns = numberOfImages;
   }

 // Setup the render window and interactor
 vtkSmartPointer<vtkRenderWindow> renderWindow =
   vtkSmartPointer<vtkRenderWindow>::New();
 renderWindow->SetSize(rendererSize * numberOfColumns,
                       rendererSize * numberOfRows);

 vtkSmartPointer<vtkRenderWindowInteractor> interactor =
   vtkSmartPointer<vtkRenderWindowInteractor>::New();
 interactor->SetRenderWindow(renderWindow);

 // Render all of the images
 std::vector<double*> viewports;

 typedef itk::ImageToVTKImageFilter<itk::Image<unsigned char, 2> >
   ConnectorType;
 typedef itk::ImageToVTKImageFilter<itk::Image<itk::RGBPixel<unsigned char>, 2> >
   RGBConnectorType;
 std::vector<ConnectorType::Pointer>    connectors; // Force the connectors to persist (not lose scope) after each iteration of the loop
 std::vector<RGBConnectorType::Pointer> RGBconnectors; // Force the connectors to persist after each iteration of the loop

 double background[6] = {.4, .5, .6, .6, .5, .4};

 vtkSmartPointer<vtkCamera> sharedCamera =
   vtkSmartPointer<vtkCamera>::New();

 for(unsigned int row = 0; row < numberOfRows; ++row)
   {
   for(unsigned int col = 0; col < numberOfColumns; ++col)
     {
     size_t i = row * numberOfColumns + col;
     // (xmin, ymin, xmax, ymax)
     double viewport[4] =
       {static_cast<double>(col) * rendererSize / (numberOfColumns * rendererSize),
        static_cast<double>(numberOfRows - (row+1)) * rendererSize / (numberOfRows * rendererSize),
        static_cast<double>(col+1)*rendererSize / (numberOfColumns * rendererSize),
        static_cast<double>(numberOfRows - row) * rendererSize / (numberOfRows * rendererSize)};
     viewports.push_back(viewport);

     // Grayscale images
     if (i < this->Images.size())
       {
       ConnectorType::Pointer connector = ConnectorType::New();
       connectors.push_back(connector);
       connector->SetInput(this->Images[i].m_Image);

       vtkSmartPointer<vtkImageActor> actor =
         vtkSmartPointer<vtkImageActor>::New();

1. if VTK_MAJOR_VERSION <= 5

       actor->SetInput(connector->GetOutput());

1. else

       connector->Update();
       actor->GetMapper()->SetInputData(connector->GetOutput());

1. endif

       // Setup renderer
       vtkSmartPointer<vtkRenderer> renderer =
         vtkSmartPointer<vtkRenderer>::New();
       renderWindow->AddRenderer(renderer);
       renderer->SetViewport(viewports[i]);
       renderer->SetBackground(background);
       if (m_ShareCamera)
         {
         renderer->SetActiveCamera(sharedCamera);
         }
       else
         {
         vtkSmartPointer<vtkCamera> aCamera =
           vtkSmartPointer<vtkCamera>::New();
         renderer->SetActiveCamera(aCamera);
         }
       std::rotate(background, background + 1, background + 6);

       if (this->Images[i].m_Description != "")
         {
         vtkSmartPointer<vtkTextProperty> textProperty =
           vtkSmartPointer<vtkTextProperty>::New();
         textProperty->SetFontSize(10);
         textProperty->SetFontFamilyToCourier();
         textProperty->SetJustificationToCentered();

         vtkSmartPointer<vtkTextMapper> textMapper =
           vtkSmartPointer<vtkTextMapper>::New();
         textMapper->SetTextProperty(textProperty);
         textMapper->SetInput(this->Images[i].m_Description.c_str());

         vtkSmartPointer<vtkActor2D> textActor =
           vtkSmartPointer<vtkActor2D>::New();
         textActor->SetMapper(textMapper);
         textActor->SetPosition(rendererSize/2, 16);
         renderer->AddActor(textActor);
         }
       if (m_Interpolate)
         {
         actor->InterpolateOn();
         }
       else
         {
         actor->InterpolateOff();
         }
       renderer->AddActor(actor);
       renderer->ResetCamera();
       }
     // RGB Images
     else if (i >= this->Images.size() && i < numberOfImages)
       {
       unsigned int j = row * numberOfColumns + col - this->Images.size();
       RGBConnectorType::Pointer connector = RGBConnectorType::New();
       RGBconnectors.push_back(connector);
       connector->SetInput(this->RGBImages[j].m_Image);

       vtkSmartPointer<vtkImageActor> actor =
         vtkSmartPointer<vtkImageActor>::New();

1. if VTK_MAJOR_VERSION <= 5

       actor->SetInput(connector->GetOutput());

1. else

       connector->Update();
       actor->GetMapper()->SetInputData(connector->GetOutput());

1. endif

       // Setup renderer
       vtkSmartPointer<vtkRenderer> renderer =
         vtkSmartPointer<vtkRenderer>::New();
       renderWindow->AddRenderer(renderer);
       renderer->SetViewport(viewports[i]);
       renderer->SetBackground(background);
       if (m_ShareCamera)
         {
         renderer->SetActiveCamera(sharedCamera);
         }
       else
         {
         vtkSmartPointer<vtkCamera> aCamera =
           vtkSmartPointer<vtkCamera>::New();
         renderer->SetActiveCamera(aCamera);
         }
       std::rotate(background, background + 1, background + 6);

       if (this->RGBImages[j].m_Description != "")
         {
         vtkSmartPointer<vtkTextProperty> textProperty =
           vtkSmartPointer<vtkTextProperty>::New();
         textProperty->SetFontSize(10);
         textProperty->SetFontFamilyToCourier();
         textProperty->SetJustificationToCentered();

         vtkSmartPointer<vtkTextMapper> textMapper =
           vtkSmartPointer<vtkTextMapper>::New();
         textMapper->SetTextProperty(textProperty);
         textMapper->SetInput(this->RGBImages[j].m_Description.c_str());

         vtkSmartPointer<vtkActor2D> textActor =
           vtkSmartPointer<vtkActor2D>::New();
         textActor->SetMapper(textMapper);
         textActor->SetPosition(rendererSize/2, 16);
         renderer->AddActor(textActor);
         }

       if (m_Interpolate)
         {
         actor->InterpolateOn();
         }
       else
         {
         actor->InterpolateOff();
         }
       renderer->AddActor(actor);
       renderer->ResetCamera();
       }
     else
       {
       // Fill empty viewports
       vtkSmartPointer<vtkRenderer> renderer =
         vtkSmartPointer<vtkRenderer>::New();
       renderWindow->AddRenderer(renderer);
       renderer->SetViewport(viewports[i]);
       renderer->SetBackground(background);
       continue;
       }
     }
   }
   renderWindow->Render();

   if( m_Snapshot )
   {
   std::string filename;
   std::stringstream temp;
   temp << m_SnapshotPath << m_SnapshotPrefix << m_Counter << ".";
   filename = temp.str();
   filename.append( m_SnapshotExtension );

   if( m_SnapshotExtension == "png" )
     {
     vtkCaptureScreen< vtkPNGWriter > capture( renderWindow );
     capture( filename );
     }
   if( ( m_SnapshotExtension == "jpg" ) || ( m_SnapshotExtension == "jpeg" ) )
     {
     vtkCaptureScreen< vtkJPEGWriter > capture( renderWindow );
     capture( filename );
     }
   if( m_SnapshotExtension == "bmp" )
     {
     vtkCaptureScreen< vtkBMPWriter > capture( renderWindow );
     capture( filename );
     }
   if( ( m_SnapshotExtension == "tif" ) || ( m_SnapshotExtension == "tiff" ) )
     {
     vtkCaptureScreen< vtkTIFFWriter > capture( renderWindow );
     capture( filename );
     }
   m_Counter++;
   }

 vtkSmartPointer<vtkInteractorStyleImage> style =
   vtkSmartPointer<vtkInteractorStyleImage>::New();
 interactor->SetInteractorStyle(style);

 if (interact)
   {
   interactor->Start();
   }

} </source>

vtkCaptureScreen.h

<source lang="cpp"> /*=========================================================================

*
*  Copyright Insight Software Consortium
*
*  Licensed under the Apache License, Version 2.0 (the "License");
*  you may not use this file except in compliance with the License.
*  You may obtain a copy of the License at
*
*         http://www.apache.org/licenses/LICENSE-2.0.txt
*
*  Unless required by applicable law or agreed to in writing, software
*  distributed under the License is distributed on an "AS IS" BASIS,
*  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
*  See the License for the specific language governing permissions and
*  limitations under the License.
*
*=========================================================================*/

1. ifndef __vtkCaptureScreen_h
2. define __vtkCaptureScreen_h

1. include <string>
2. include "vtkSmartPointer.h"
3. include "vtkWindowToImageFilter.h"
4. include "vtkRenderWindow.h"

template < class TImageWriter > class vtkCaptureScreen

 {

public:

 typedef TImageWriter ImageWriterType;

 vtkCaptureScreen( vtkRenderWindow* iRenderer ) : m_Renderer ( iRenderer )
   {}

 vtkCaptureScreen() : m_Renderer( NULL )
   {}

 ~vtkCaptureScreen( )
   {}

 void operator( ) ( const std::string& iFileName ) const
   {
   Capture( m_Renderer, iFileName );
   }

 void operator( ) ( vtkRenderWindow* iRenderer,
                    const std::string& iFileName ) const
   {
   m_Renderer = iRenderer;
   Capture( m_Renderer, iFileName );
   }

 private:
   vtkCaptureScreen ( const vtkCaptureScreen& );
   void operator = ( const vtkCaptureScreen& );

   vtkRenderWindow* m_Renderer;

   void Capture( vtkRenderWindow* iRenderer,
                 const std::string& iFileName ) const
     {
     if( iRenderer )
       {
       vtkSmartPointer< vtkWindowToImageFilter > Dumper =
           vtkSmartPointer< vtkWindowToImageFilter >::New( );
       Dumper->SetInput( iRenderer );
       Dumper->Update( );

       vtkSmartPointer< ImageWriterType > writer =
           vtkSmartPointer< ImageWriterType >::New( );
       writer->SetFileName ( iFileName.c_str( ) );
       writer->SetInputConnection ( Dumper->GetOutputPort( ) );
       writer->Write( );
       }
     }
 };

1. endif

</source>