KnownLengthArray

Repository source: 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)

Question

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Code¶

KnownLengthArray.cxx

#include <vtkFloatArray.h>
#include <vtkNew.h>

int main(int, char*[])
{
  vtkNew<vtkFloatArray> distances;
  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 3.12 FATAL_ERROR)

project(KnownLengthArray)

find_package(VTK COMPONENTS 
  CommonCore
)

if (NOT VTK_FOUND)
  message(FATAL_ERROR "KnownLengthArray: Unable to find the VTK build folder.")
endif()

# Prevent a "command line is too long" failure in Windows.
set(CMAKE_NINJA_FORCE_RESPONSE_FILE "ON" CACHE BOOL "Force Ninja to use response files.")
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}
)

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.