ResizeImage

VTKEx/Cxx/Images/ResizeImage

Description

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

Several window functions are provided. See this article for a description og window functions. vtkImageResize maintains the physical size of the image.

Note

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

Seealso

The paper "Some windows with very good sidelobe behavior" describes the windows implemented in vtkImageSincInterpolator.

Question

If you have a simple question about this example contact us at VTKExProject If your question is more complex and may require extended discussion, please use the VTK Discourse Forum

Code

ResizeImage.cxx

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

#include <vtkImageReader2Factory.h>
#include <vtkImageReader2.h>
#include <vtkCamera.h>
#include <vtkImageActor.h>
#include <vtkImageCanvasSource2D.h>
#include <vtkImageData.h>
#include <vtkImageMapper3D.h>
#include <vtkRenderer.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkInteractorStyleImage.h>
#include <vtkNamedColors.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<vtkImageReader2Factory> readerFactory =
      vtkSmartPointer<vtkImageReader2Factory>::New();
    vtkSmartPointer<vtkImageReader2> reader;
    reader.TakeReference(
      readerFactory->CreateImageReader2(argv[1]));
    reader->SetFileName(argv[1]);
    reader->Update();

    imageData = reader->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();
  interpolator->UseWindowParameterOn();
  if (windowFunction >= 0 && windowFunction <= 10)
  {
    interpolator->SetWindowFunction(windowFunction);
  }

  vtkSmartPointer<vtkImageResize> resize =
    vtkSmartPointer<vtkImageResize>::New();
  resize->SetInputData(imageData);
  resize->SetInterpolator(interpolator);
  resize->SetOutputDimensions(newSize[0], newSize[1], 1);
  resize->InterpolateOn();

  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());
  imageActor->InterpolateOff();

  // Setup renderer
  vtkSmartPointer<vtkNamedColors> colors =
    vtkSmartPointer<vtkNamedColors>::New();

  vtkSmartPointer<vtkRenderer> renderer =
    vtkSmartPointer<vtkRenderer>::New();
  renderer->AddActor(imageActor);
  renderer->SetBackground(colors->GetColor3d("Burlywood").GetData());
  renderer->ResetCamera();
  renderer->GetActiveCamera()->Dolly(5.0);
  renderer->ResetCameraClippingRange();

  // Setup render window
  vtkSmartPointer<vtkRenderWindow> renderWindow =
    vtkSmartPointer<vtkRenderWindow>::New();
  renderWindow->AddRenderer(renderer);
  renderWindow->SetSize(1280, 1024);

  // 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);
  renderWindow->Render();
  renderWindowInteractor->Initialize();

  renderWindowInteractor->Start();

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(ResizeImage)

find_package(VTK COMPONENTS 
  vtkvtkCommonColor
  vtkvtkCommonCore
  vtkvtkCommonDataModel
  vtkvtkIOImage
  vtkvtkImagingCore
  vtkvtkImagingSources
  vtkvtkInteractionStyle
  vtkvtkRenderingContextOpenGL2
  vtkvtkRenderingCore
  vtkvtkRenderingFreeType
  vtkvtkRenderingGL2PSOpenGL2
  vtkvtkRenderingOpenGL2 QUIET)
if (NOT VTK_FOUND)
  message("Skipping ResizeImage: ${VTK_NOT_FOUND_MESSAGE}")
  return ()
endif()
message (STATUS "VTK_VERSION: ${VTK_VERSION}")
if (VTK_VERSION VERSION_LESS "8.90.0")
  # old system
  include(${VTK_USE_FILE})
  add_executable(ResizeImage MACOSX_BUNDLE ResizeImage.cxx )
  target_link_libraries(ResizeImage PRIVATE ${VTK_LIBRARIES})
else ()
  # include all components
  add_executable(ResizeImage MACOSX_BUNDLE ResizeImage.cxx )
  target_link_libraries(ResizeImage PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS ResizeImage
    MODULES ${VTK_LIBRARIES}
    )
endif ()

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

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