# ResizeImage

VTKExamples/Cxx/Images/ResizeImage

### Description

Resize an image using a sinc interpolator. Without command line arguments, the example resize a synthetic image. A jpeg file can be passed on the command lines. The new dimensions can also be passed as well as an integer specifying the sinc interpolator. See {{VTKDoxygenURL|vtkImageSincInterpolator}} for details. A -1 turns off interpolation.

ImageResize maintains the physical size of the image.

Note

This example was inspired by a question asked by Qiang Wang.

### Code

ResizeImage.cxx

    #include <vtkImageResize.h>
    #include "vtkImageSincInterpolator.h"

    #include <vtkVersion.h>
    #include <vtkImageActor.h>
    #include <vtkImageCanvasSource2D.h>
    #include <vtkImageData.h>
    #include <vtkJPEGReader.h>
    #include <vtkImageMapper3D.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkInteractorStyleImage.h>
    #include <vtkSmartPointer.h>

    int main(int argc, char *argv[])
    {
      vtkSmartPointer<vtkImageData> imageData;

      int newSize[2] = {200, 10};
      int windowFunction = 0;

      // Verify input arguments
      if ( argc > 1 )
      {
        //Read the image
        vtkSmartPointer<vtkJPEGReader> jpegReader =
          vtkSmartPointer<vtkJPEGReader>::New();
        jpegReader->SetFileName ( argv[1] );
        jpegReader->Update();

        imageData = jpegReader->GetOutput();
        if (argc >3)
        {
          newSize[0] = atoi(argv[2]);
          newSize[1] = atoi(argv[3]);
        }
        if (argc > 4)
        {
          windowFunction = atoi(argv[4]);
        }
      }
      else
      {
        vtkSmartPointer<vtkImageCanvasSource2D> canvasSource =
          vtkSmartPointer<vtkImageCanvasSource2D>::New();
        canvasSource->SetExtent(0, 100, 0, 100, 0, 0);
        canvasSource->SetScalarTypeToUnsignedChar();
        canvasSource->SetNumberOfScalarComponents(3);
        canvasSource->SetDrawColor(127, 127, 100);
        canvasSource->FillBox(0, 100, 0, 100);
        canvasSource->SetDrawColor(100, 255, 255);
        canvasSource->FillTriangle(10, 10, 25, 10, 25, 25);
        canvasSource->SetDrawColor(255, 100, 255);
        canvasSource->FillTube(75, 75, 0, 75, 5.0);
        canvasSource->Update();
        imageData = canvasSource->GetOutput();
      }

      vtkSmartPointer<vtkImageSincInterpolator> interpolator =
        vtkSmartPointer<vtkImageSincInterpolator>::New();
      if (windowFunction >= 0 && windowFunction <= 10)
      {
        interpolator->SetWindowFunction(windowFunction);
      }

      vtkSmartPointer<vtkImageResize> resize =
        vtkSmartPointer<vtkImageResize>::New();
    #if VTK_MAJOR_VERSION <= 5
      resize->SetInput(imageData);
    #else
      resize->SetInputData(imageData);
    #endif
      resize->SetOutputDimensions(newSize[0], newSize[1], 1);
      resize->Update();
      if (windowFunction < 0)
      {
        resize->InterpolateOff();
        std::cout << "Using nearest neighbor interpolation" << std::endl;;
      }
      else
      {
        std::cout << "Using window function : "
                  << interpolator->GetWindowFunctionAsString() << std::endl;;
      }

      // Create an image actor to display the image
      vtkSmartPointer<vtkImageActor> imageActor =
        vtkSmartPointer<vtkImageActor>::New();
      imageActor->GetMapper()->SetInputConnection(resize->GetOutputPort());

     // Setup renderer
      vtkSmartPointer<vtkRenderer> renderer =
        vtkSmartPointer<vtkRenderer>::New();
      renderer->AddActor(imageActor);
      renderer->ResetCamera();

      // Setup render window
      vtkSmartPointer<vtkRenderWindow> renderWindow =
        vtkSmartPointer<vtkRenderWindow>::New();
      renderWindow->AddRenderer(renderer);

      // Setup render window interactor
      vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      vtkSmartPointer<vtkInteractorStyleImage> style =
        vtkSmartPointer<vtkInteractorStyleImage>::New();

      renderWindowInteractor->SetInteractorStyle(style);

      // Render and start interaction
      renderWindowInteractor->SetRenderWindow(renderWindow);
      renderWindowInteractor->Initialize();

      renderWindowInteractor->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(ResizeImage)

    find_package(VTK REQUIRED)
    include(${VTK_USE_FILE})

    add_executable(ResizeImage MACOSX_BUNDLE ResizeImage.cxx )

    target_link_libraries(ResizeImage ${VTK_LIBRARIES})

### Download and Build ResizeImage

Click here to download ResizeImage and its CMakeLists.txt file. Once the tarball ResizeImage.tar has been downloaded and extracted,

    cd ResizeImage/build

If VTK is installed:

    cmake ..

If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:

    cmake -DVTK_DIR:PATH=/home/me/vtk_build ..

Build the project:

    make

and run it:

    ./ResizeImage

WINDOWS USERS PLEASE NOTE: Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.