# InteractWithImage

VTKExamples/Cxx/Images/InteractWithImage

### Description

This example shows how to display an image and zoom/pan/adjust brightness interactively. A picture of the bunny is provided for the demo.

### Code

InteractWithImage.cxx

    #include <vtkSmartPointer.h>

    #include <vtkImageReader2Factory.h>
    #include <vtkImageReader2.h>

    #include <vtkImageMapper3D.h>
    #include <vtkImageActor.h> // Note: this is a 3D actor (c.f. vtkImageMapper which is 2D)
    #include <vtkRenderer.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkInteractorStyleImage.h>
    #include <vtkNamedColors.h>

    int main(int argc, char* argv[])
    {
      // Parse input arguments
      if ( argc != 2 )
      {
        std::cout << "Required parameters: Filename" << std::endl;
        return EXIT_FAILURE;
      }
      std::string inputFilename = argv[1];

      // Read the image
      vtkSmartPointer<vtkImageReader2Factory> readerFactory =
        vtkSmartPointer<vtkImageReader2Factory>::New();
      vtkSmartPointer<vtkImageReader2> reader;
      reader.TakeReference(
        readerFactory->CreateImageReader2(argv[1]));
      reader->SetFileName(argv[1]);

      // Create an actor
      vtkSmartPointer<vtkImageActor> actor =
        vtkSmartPointer<vtkImageActor>::New();
      actor->GetMapper()->SetInputConnection(reader->GetOutputPort());

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

      vtkSmartPointer<vtkRenderer> renderer =
        vtkSmartPointer<vtkRenderer>::New();
      renderer->AddActor(actor);
      renderer->ResetCamera();
      renderer->SetBackground(colors->GetColor3d("Burlywood").GetData());

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

      // Setup render window interactor
      vtkSmartPointer<vtkRenderWindowInteractor> interactor =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      interactor->SetRenderWindow(window);

      // Setup interactor style (this is what implements the zooming, panning and brightness adjustment functionality)
      vtkSmartPointer<vtkInteractorStyleImage> style =
        vtkSmartPointer<vtkInteractorStyleImage>::New();
      interactor->SetInteractorStyle(style);

      // Render and start interaction
      interactor->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(InteractWithImage)

    find_package(VTK COMPONENTS
      vtkCommonColor
      vtkCommonCore
      vtkIOImage
      vtkInteractionStyle
      vtkRenderingContextOpenGL2
      vtkRenderingCore
      vtkRenderingFreeType
      vtkRenderingGL2PSOpenGL2
      vtkRenderingOpenGL2 QUIET)
    if (NOT VTK_FOUND)
      message("Skipping InteractWithImage: ${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(InteractWithImage MACOSX_BUNDLE InteractWithImage.cxx )
      target_link_libraries(InteractWithImage PRIVATE ${VTK_LIBRARIES})
    else ()
      # include all components
      add_executable(InteractWithImage MACOSX_BUNDLE InteractWithImage.cxx )
      target_link_libraries(InteractWithImage PRIVATE ${VTK_LIBRARIES})
      # vtk_module_autoinit is needed
      vtk_module_autoinit(
        TARGETS InteractWithImage
        MODULES ${VTK_LIBRARIES}
        )
    endif ()

### Download and Build InteractWithImage

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

    cd InteractWithImage/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:

    ./InteractWithImage

WINDOWS USERS

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