CombineImages

VTKExamples/Cxx/Images/CombineImages


Description

This example takes two images and super imposes them. The opacity of each image can be set to control how they are combined.

Code

CombineImages.cxx

#include <vtkImageBlend.h>
#include <vtkSmartPointer.h>

#include <vtkImageReader2Factory.h>
#include <vtkImageReader2.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkImageData.h>
#include <vtkImageViewer2.h>
#include <vtkNamedColors.h>

#include <string>

int main ( int argc, char* argv[] )
{
  // Parse input arguments
  if ( argc != 3 )
  {
    std::cerr << "Usage: " << argv[0]
              << " Input1Filename Input2Filename" << std::endl;
    return EXIT_FAILURE;
  }

  // Read the images
  vtkSmartPointer<vtkImageReader2Factory> readerFactory =
    vtkSmartPointer<vtkImageReader2Factory>::New();
  vtkImageReader2 *imgReader1 = readerFactory->CreateImageReader2(argv[1]);
  imgReader1->SetFileName(argv[1]);

  vtkImageReader2 *imgReader2 = readerFactory->CreateImageReader2(argv[2]);
  imgReader2->SetFileName(argv[2]);

  // Combine the images (blend takes multiple connections on the 0th input port)
  vtkSmartPointer<vtkImageBlend> blend =
    vtkSmartPointer<vtkImageBlend>::New();
  blend->AddInputConnection(imgReader1->GetOutputPort());
  blend->AddInputConnection(imgReader2->GetOutputPort());
  blend->SetOpacity(0,.5);
  blend->SetOpacity(1,.5);

  // Display the result
  vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
    vtkSmartPointer<vtkRenderWindowInteractor>::New();

  vtkSmartPointer<vtkNamedColors> colors =
    vtkSmartPointer<vtkNamedColors>::New();
  vtkSmartPointer<vtkImageViewer2> imageViewer =
    vtkSmartPointer<vtkImageViewer2>::New();
  imageViewer->SetInputConnection(blend->GetOutputPort());
  imageViewer->SetupInteractor(renderWindowInteractor);
  imageViewer->GetRenderer()->ResetCamera();
  imageViewer->GetRenderer()->SetBackground(
    colors->GetColor3d("Wheat").GetData());

  renderWindowInteractor->Initialize();
  renderWindowInteractor->Start();

  imgReader1->Delete();
  imgReader2->Delete();
  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 2.8)

PROJECT(CombineImages)

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

add_executable(CombineImages MACOSX_BUNDLE CombineImages.cxx )

target_link_libraries(CombineImages ${VTK_LIBRARIES})

Download and Build CombineImages

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

cd CombineImages/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:

./CombineImages

WINDOWS USERS

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