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ResizeImage

vtk-examples/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 question about this example, please use the VTK Discourse Forum

Code

ResizeImage.cxx

#include <vtkCamera.h>
#include <vtkImageActor.h>
#include <vtkImageCanvasSource2D.h>
#include <vtkImageData.h>
#include <vtkImageMapper3D.h>
#include <vtkImageReader2.h>
#include <vtkImageReader2Factory.h>
#include <vtkImageResize.h>
#include <vtkImageSincInterpolator.h>
#include <vtkInteractorStyleImage.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkSmartPointer.h>

#include <array>

int main(int argc, char* argv[])
{
  vtkNew<vtkNamedColors> colors;

  vtkSmartPointer<vtkImageData> imageData;

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

  // Verify input arguments
  // e.g. Gourds2.jpg 1280 1024 5
  if (argc > 1)
  {
    // Read the image
    vtkNew<vtkImageReader2Factory> readerFactory;
    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
  {
    std::array<double, 3> drawColor1{0, 0, 0};
    auto color1 = colors->GetColor3ub("Gray").GetData();
    std::array<double, 3> drawColor2{0, 0, 0};
    auto color2 = colors->GetColor3ub("Aquamarine").GetData();
    std::array<double, 3> drawColor3{0, 0, 0};
    auto color3 = colors->GetColor3ub("Violet").GetData();
    for (auto i = 0; i < 3; ++i)
    {
      drawColor1[i] = color1[i];
      drawColor2[i] = color2[i];
      drawColor3[i] = color3[i];
    }

    vtkNew<vtkImageCanvasSource2D> canvasSource;
    canvasSource->SetExtent(0, 100, 0, 100, 0, 0);
    canvasSource->SetScalarTypeToUnsignedChar();
    canvasSource->SetNumberOfScalarComponents(3);
    canvasSource->SetDrawColor(drawColor1.data());
    canvasSource->FillBox(0, 100, 0, 100);
    canvasSource->SetDrawColor(drawColor2.data());
    canvasSource->FillTriangle(10, 10, 25, 10, 25, 25);
    canvasSource->SetDrawColor(drawColor3.data());
    canvasSource->FillTube(75, 75, 0, 75, 5.0);
    canvasSource->Update();
    imageData = canvasSource->GetOutput();
  }

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

  vtkNew<vtkImageResize> resize;
  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
  vtkNew<vtkImageActor> imageActor;
  imageActor->GetMapper()->SetInputConnection(resize->GetOutputPort());
  imageActor->InterpolateOff();

  // Setup renderer
  vtkNew<vtkRenderer> renderer;
  renderer->AddActor(imageActor);
  renderer->SetBackground(colors->GetColor3d("Burlywood").GetData());
  renderer->ResetCamera();
  renderer->GetActiveCamera()->Dolly(5.0);
  renderer->ResetCameraClippingRange();

  // Setup render window
  vtkNew<vtkRenderWindow> renderWindow;
  renderWindow->AddRenderer(renderer);
  renderWindow->SetSize(1280, 1024);
  renderWindow->SetWindowName("ResizeImage");

  // Setup render window interactor
  vtkNew<vtkRenderWindowInteractor> renderWindowInteractor;
  vtkNew<vtkInteractorStyleImage> style;

  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 3.12 FATAL_ERROR)

project(ResizeImage)

find_package(VTK COMPONENTS 
  CommonColor
  CommonCore
  CommonDataModel
  IOImage
  ImagingCore
  ImagingSources
  InteractionStyle
  RenderingContextOpenGL2
  RenderingCore
  RenderingFreeType
  RenderingGL2PSOpenGL2
  RenderingOpenGL2
  QUIET
)

if (NOT VTK_FOUND)
  message(FATAL_ERROR "ResizeImage: Unable to find the VTK build folder.")
endif()

# Prevent a "command line is too long" failure in Windows.
set(CMAKE_NINJA_FORCE_RESPONSE_FILE "ON" CACHE BOOL "Force Ninja to use response files.")
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}
)

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.