IterateImageData
VTKExamples/Cxx/ImageData/IterateImageData
Description¶
This example demonstrates how to set and access locations in a 3D image.
Code¶
IterateImageData.cxx
#include <vtkVersion.h> #include <vtkSmartPointer.h> #include <vtkImageData.h> int main(int, char *[]) { // Create an image data vtkSmartPointer<vtkImageData> imageData = vtkSmartPointer<vtkImageData>::New(); // Specify the size of the image data imageData->SetDimensions(2,3,1); #if VTK_MAJOR_VERSION <= 5 imageData->SetNumberOfScalarComponents(1); imageData->SetScalarTypeToDouble(); #else imageData->AllocateScalars(VTK_DOUBLE,1); #endif int* dims = imageData->GetDimensions(); // int dims[3]; // can't do this std::cout << "Dims: " << " x: " << dims[0] << " y: " << dims[1] << " z: " << dims[2] << std::endl; std::cout << "Number of points: " << imageData->GetNumberOfPoints() << std::endl; std::cout << "Number of cells: " << imageData->GetNumberOfCells() << std::endl; // Fill every entry of the image data with "2.0" for (int z = 0; z < dims[2]; z++) { for (int y = 0; y < dims[1]; y++) { for (int x = 0; x < dims[0]; x++) { double* pixel = static_cast<double*>(imageData->GetScalarPointer(x,y,z)); pixel[0] = 2.0; } } } // Retrieve the entries from the image data and print them to the screen for (int z = 0; z < dims[2]; z++) { for (int y = 0; y < dims[1]; y++) { for (int x = 0; x < dims[0]; x++) { double* pixel = static_cast<double*>(imageData->GetScalarPointer(x,y,z)); // do something with v std::cout << pixel[0] << " "; } std::cout << std::endl; } std::cout << std::endl; } // Access the data linearly /* vtkSmartPointer<vtkImageData> image = vtkSmartPointer<vtkImageData>::New(); image->SetExtent(0,1,0,1,0,0); image->SetScalarTypeToInt(); image->SetNumberOfScalarComponents(1); int* pixel; pixel = static_cast<int*>(image->GetScalarPointer(0,0,0)); pixel[0] = 1; pixel = static_cast<int*>(image->GetScalarPointer(1,0,0)); pixel[0] = 2; pixel = static_cast<int*>(image->GetScalarPointer(0,1,0)); pixel[0] = 3; pixel = static_cast<int*>(image->GetScalarPointer(1,1,0)); pixel[0] = 4; vtkIntArray* scalars = vtkIntArray::SafeDownCast(image->GetPointData()->GetArray("ImageScalars")); std::cout << "Scalars has " << scalars->GetNumberOfComponents() << " components" << std::endl; std::cout << "Scalars has " << scalars->GetNumberOfTuples() << " tuples" << std::endl; for(vtkIdType i = 0; i < scalars->GetNumberOfTuples(); i++) { std::cout << scalars->GetValue(i) << std::endl; } */ return EXIT_SUCCESS; }
CMakeLists.txt¶
cmake_minimum_required(VERSION 2.8) PROJECT(IterateImageData) find_package(VTK REQUIRED) include(${VTK_USE_FILE}) add_executable(IterateImageData MACOSX_BUNDLE IterateImageData.cxx) target_link_libraries(IterateImageData ${VTK_LIBRARIES})
Download and Build IterateImageData¶
Danger
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Click here to download IterateImageData and its CMakeLists.txt file. Once the tarball IterateImageData.tar has been downloaded and extracted,
cd IterateImageData/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:
./IterateImageData
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.