KnownLengthArray

VTKExamples/Cxx/Utilities/KnownLengthArray

Description

This example creates a VTK style float array. This can be easily interchanged with vtkIntArray, vtkDoubleArray, etc.

The terminology is as follows:

  • SetNumberOfComponents(): sets the number of elements that a tuple in the array will have. See VectorArrayKnownLength for an example with tuples with more than one element.

  • SetNumberOfValues(): sets the number of tuples the array will have. See UnknownLengthArray for an example where the number of values is not known in advance.

Other Languages

See (Java)

Code

KnownLengthArray.cxx

#include <vtkSmartPointer.h>
#include <vtkFloatArray.h>

int main(int, char *[])
{
  vtkSmartPointer<vtkFloatArray> distances =
    vtkSmartPointer<vtkFloatArray>::New();
  distances->SetName("Distances");
  distances->SetNumberOfComponents(1);
  distances->SetNumberOfValues(5);

  //set values
  for(vtkIdType i = 0; i < distances->GetNumberOfTuples(); i++)
  {
    float f = (float)i + 0.1;
    distances->SetValue(i, f);
  }

  //get values
  for(vtkIdType i = 0; i < distances->GetNumberOfTuples(); i++)
  {
    float f = distances->GetValue(i);
    std::cout << f << std::endl;
  }

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(KnownLengthArray)

find_package(VTK COMPONENTS 
  vtkCommonCore QUIET)
if (NOT VTK_FOUND)
  message("Skipping KnownLengthArray: ${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(KnownLengthArray MACOSX_BUNDLE KnownLengthArray.cxx )
  target_link_libraries(KnownLengthArray PRIVATE ${VTK_LIBRARIES})
else ()
  # include all components
  add_executable(KnownLengthArray MACOSX_BUNDLE KnownLengthArray.cxx )
  target_link_libraries(KnownLengthArray PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS KnownLengthArray
    MODULES ${VTK_LIBRARIES}
    )
endif () 

Download and Build KnownLengthArray

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

cd KnownLengthArray/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:

./KnownLengthArray

WINDOWS USERS

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