UnknownLengthArray

VTKExamples/Cxx/Utilities/UnknownLengthArray

Description

The only difference between this example and the KnownLengthArray example is that SetNumberOfValues() is not called, and SetValue() is replaced by InsertNextValue().

Other Languages

See (Java)

Question

If you have a simple question about this example contact us at VTKExamplesProject If your question is more complex and may require extended discussion, please use the VTK Discourse Forum

Code

UnknownLengthArray.cxx

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

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

  //set values
  for(vtkIdType i = 0; i < 5; i++)
  {
    float f = (float)i + 0.1;
    //this will allocate memory as necessary
    distances->InsertNextValue(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(UnknownLengthArray)

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

Download and Build UnknownLengthArray

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

cd UnknownLengthArray/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:

./UnknownLengthArray

WINDOWS USERS

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