ImageMagnify
VTKExamples/Cxx/Images/ImageMagnify
Description¶
vtkImageMagnify increases the dimensions of an image by integral magnification factors. It also adjusts the spacing of the pixels so that the magnified image covers the same region as the original image. To stretch the image, the pixel spacing needs to be adjusted. This example uses vtkImageChangeInformation to modify the magnified image's spacing. The result is an image that has increased numbers of pixels and is stretched in the magnified directions.
Code¶
ImageMagnify.cxx
#include <vtkImageActor.h> #include <vtkInteractorStyleImage.h> #include <vtkImageData.h> #include <vtkImageMapper3D.h> #include <vtkRenderer.h> #include <vtkRenderWindow.h> #include <vtkRenderWindowInteractor.h> #include <vtkSmartPointer.h> #include <vtkPNGReader.h> #include <vtkImageMagnify.h> #include <vtkImageChangeInformation.h> int main(int argc, char *argv[]) { // Handle the arguments if(argc < 2) { std::cout << "Required arguments: filename.png" << std::endl; return EXIT_FAILURE; } // Read the image vtkSmartPointer<vtkPNGReader> reader = vtkSmartPointer<vtkPNGReader>::New(); reader->SetFileName(argv[1]); // Increase the dimensions of the image vtkSmartPointer<vtkImageMagnify> magnifyFilter = vtkSmartPointer<vtkImageMagnify>::New(); magnifyFilter->SetInputConnection(reader->GetOutputPort()); magnifyFilter->SetMagnificationFactors(2,1,1); magnifyFilter->Update(); // Adjust the spacing of the magnified image. This will stretch the // image vtkSmartPointer<vtkImageChangeInformation> changeFilter = vtkSmartPointer<vtkImageChangeInformation>::New(); changeFilter->SetInputConnection(magnifyFilter->GetOutputPort()); changeFilter->SetSpacingScale( magnifyFilter->GetMagnificationFactors()[0], magnifyFilter->GetMagnificationFactors()[1], magnifyFilter->GetMagnificationFactors()[2]); vtkSmartPointer<vtkImageActor> originalActor = vtkSmartPointer<vtkImageActor>::New(); originalActor->GetMapper()->SetInputConnection( reader->GetOutputPort()); vtkSmartPointer<vtkImageActor> magnifiedActor = vtkSmartPointer<vtkImageActor>::New(); magnifiedActor->GetMapper()->SetInputConnection( changeFilter->GetOutputPort()); // Define viewport ranges // (xmin, ymin, xmax, ymax) double originalViewport[4] = {0.0, 0.0, 0.5, 1.0}; double magnifiedViewport[4] = {0.5, 0.0, 1.0, 1.0}; // Setup renderers vtkSmartPointer<vtkRenderer> originalRenderer = vtkSmartPointer<vtkRenderer>::New(); originalRenderer->SetViewport(originalViewport); originalRenderer->AddActor(originalActor); originalRenderer->ResetCamera(); originalRenderer->SetBackground(.4, .5, .6); vtkSmartPointer<vtkRenderer> magnifiedRenderer = vtkSmartPointer<vtkRenderer>::New(); magnifiedRenderer->SetViewport(magnifiedViewport); magnifiedRenderer->AddActor(magnifiedActor); magnifiedRenderer->ResetCamera(); magnifiedRenderer->SetBackground(.4, .5, .7); vtkSmartPointer<vtkRenderWindow> renderWindow = vtkSmartPointer<vtkRenderWindow>::New(); renderWindow->SetSize(600, 300); renderWindow->AddRenderer(originalRenderer); renderWindow->AddRenderer(magnifiedRenderer); vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor = vtkSmartPointer<vtkRenderWindowInteractor>::New(); vtkSmartPointer<vtkInteractorStyleImage> style = vtkSmartPointer<vtkInteractorStyleImage>::New(); renderWindowInteractor->SetInteractorStyle(style); renderWindowInteractor->SetRenderWindow(renderWindow); renderWindowInteractor->Initialize(); renderWindowInteractor->Start(); return EXIT_SUCCESS; }
CMakeLists.txt¶
cmake_minimum_required(VERSION 2.8) PROJECT(ImageMagnify) find_package(VTK REQUIRED) include(${VTK_USE_FILE}) add_executable(ImageMagnify MACOSX_BUNDLE ImageMagnify.cxx) target_link_libraries(ImageMagnify ${VTK_LIBRARIES})
Download and Build ImageMagnify¶
Danger
The generation of tar files has not been ported to the new VTKExamples. Some tarballs may be missing or out-of-date.
Click here to download ImageMagnify and its CMakeLists.txt file. Once the tarball ImageMagnify.tar has been downloaded and extracted,
cd ImageMagnify/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:
./ImageMagnify
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.