ITK/Examples/Meshes/AddPointsAndEdges

This example demonstrates how to add points and edges to a mesh.

AddPointsAndEdges.cxx

<source lang="cpp">

1. include "itkMesh.h"
2. include "itkLineCell.h"

const unsigned int Dimension = 3; typedef itk::Mesh< float, Dimension > MeshType;

MeshType::Pointer CreatePointOnlyMesh(); void CreateMeshWithEdges();

int main(int, char *[]) {

 //CreatePointOnlyMesh();
 CreateMeshWithEdges();

 return 0;

}

MeshType::Pointer CreatePointOnlyMesh() {

 MeshType::Pointer  mesh = MeshType::New();

 // Create points
 MeshType::PointType p0,p1,p2,p3;

 p0[0]= -1.0; p0[1]= -1.0; p0[2]= 0.0; // first  point ( -1, -1, 0 )
 p1[0]=  1.0; p1[1]= -1.0; p1[2]= 0.0; // second point (  1, -1, 0 )
 p2[0]=  1.0; p2[1]=  1.0; p2[2]= 0.0; // third  point (  1,  1, 0 )
 p3[0]=  1.0; p3[1]=  1.0; p3[2]= 1.0; // third  point (  1,  1, 1 )

 mesh->SetPoint( 0, p0 );
 mesh->SetPoint( 1, p1 );
 mesh->SetPoint( 2, p2 );
 mesh->SetPoint( 3, p3 );

 std::cout << "Points = " << mesh->GetNumberOfPoints() << std::endl;

 // Access points
 typedef MeshType::PointsContainer::Iterator     PointsIterator;

 PointsIterator  pointIterator = mesh->GetPoints()->Begin();  

 PointsIterator end = mesh->GetPoints()->End();
 while( pointIterator != end ) 
   {
   MeshType::PointType p = pointIterator.Value();  // access the point
   std::cout << p << std::endl;                    // print the point
   ++pointIterator;                                // advance to next point
   }

 return mesh;

}

void CreateMeshWithEdges() {

 MeshType::Pointer mesh = CreatePointOnlyMesh();

 typedef MeshType::CellType::CellAutoPointer         CellAutoPointer;
 typedef itk::LineCell< MeshType::CellType >         LineType;
 
 // Create a link to the previous point in the column (below the current point)
 CellAutoPointer colline;
 colline.TakeOwnership(  new LineType  );

 //unsigned int pointId0 = 0;
 //unsigned int pointId1 = 1;

 unsigned int pointId0 = 2;
 unsigned int pointId1 = 3;

 colline->SetPointId(0, pointId0); // line between points 0 and 1
 colline->SetPointId(1, pointId1);
 //std::cout << "Linked point: " << MeshIndex << " and " << MeshIndex - 1 << std::endl;
 mesh->SetCell( 0, colline );

 typedef MeshType::CellsContainer::Iterator  CellIterator;
 CellIterator  cellIterator = mesh->GetCells()->Begin();
 CellIterator  CellsEnd          = mesh->GetCells()->End();

 while( cellIterator != CellsEnd ) 
   {
   MeshType::CellType * cellptr = cellIterator.Value();
   LineType * line = dynamic_cast<LineType *>( cellptr );

   long unsigned int* linePoint0 = line->PointIdsBegin();
   //long unsigned int* linePoint1 = line->PointIdsEnd();
   long unsigned int* linePoint1 = linePoint0+1;
   std::cout << "line first point id: " << *linePoint0 << std::endl;
   std::cout << "line second point id: " << *linePoint1 << std::endl;

   ++cellIterator;
   }

}

</source>

CMakeLists.txt

<syntaxhighlight lang="cmake"> cmake_minimum_required(VERSION 3.9.5)

project(AddPointsAndEdges)

find_package(ITK REQUIRED) include(${ITK_USE_FILE}) if (ITKVtkGlue_LOADED)

 find_package(VTK REQUIRED)
 include(${VTK_USE_FILE})

endif()

add_executable(AddPointsAndEdges MACOSX_BUNDLE AddPointsAndEdges.cxx)

if( "${ITK_VERSION_MAJOR}" LESS 4 )

 target_link_libraries(AddPointsAndEdges ITKReview ${ITK_LIBRARIES})

else( "${ITK_VERSION_MAJOR}" LESS 4 )

 target_link_libraries(AddPointsAndEdges ${ITK_LIBRARIES})

endif( "${ITK_VERSION_MAJOR}" LESS 4 )

</syntaxhighlight>

Download and Build AddPointsAndEdges

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

cd AddPointsAndEdges/build

• If ITK is installed:

cmake ..

• If ITK is not installed but compiled on your system, you will need to specify the path to your ITK build:

cmake -DITK_DIR:PATH=/home/me/itk_build ..

Build the project:

make

and run it:

./AddPointsAndEdges

WINDOWS USERS PLEASE NOTE: Be sure to add the ITK bin directory to your path. This will resolve the ITK dll's at run time.

Building All of the Examples

Many of the examples in the ITK Wiki Examples Collection require VTK. You can build all of the the examples by following these instructions. If you are a new VTK user, you may want to try the Superbuild which will build a proper ITK and VTK.

ItkVtkGlue

ITK >= 4

For examples that use QuickView (which depends on VTK), you must have built ITK with Module_ITKVtkGlue=ON.

ITK < 4

Some of the ITK Examples require VTK to display the images. If you download the entire ITK Wiki Examples Collection, the ItkVtkGlue directory will be included and configured. If you wish to just build a few examples, then you will need to download ItkVtkGlue and build it. When you run cmake it will ask you to specify the location of the ItkVtkGlue binary directory.