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
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.