vtkCellLinks.GetCells (vtkIdType ptId) not accessible from Java wrapper

Support
1

I use vtk 9.5 with java wrapper. vtkCellLinks can be instantiated and built (with BuildLinks()), but GetLink() and GetCells() simply do not appear in the Java wrapper. I can’t figure out how vtkCellLinks can be useful if links cannot be retrieved. Maybe (probably) I miss something.
How can I do to retrieve my links ? Do I have to build in Java a ‘parallel’ structure ?

Any hint will be gratefully appreciated.

2

You can forget about GetLink(). The return type is not a vtkObject so it won’t be wrapped.

The Java wrapper code does not seem to recognise the return type for GetCells(). I would suggest changing

vtkIdType* GetCells(vtkIdType ptId)

to

long long* GetCells(vtkIdType ptId)

and then rebuild.

3

Well that doesn’t work, so I tried adding a new method

void GetLink(vtkIdType ptId, vtkIdType& nCells, vtkIdType*& cells) VTK_SIZEHINT(cells, nCells);

void vtkCellLinks::GetLink(vtkIdType ptId, vtkIdType& nCells, vtkIdType*& cells) 
{
  Link& link = this->Array[ptId];
  nCells = link.ncells;
  cells = link.cells;
}

but it doesn’t generate Java wrapper code either. However there are other VTK classes which generate correctly e.g. const vtkIdType* vtkWedge::GetFaceArray()

This is a mystery to me. @dgobbi Do you know where the translation from vtkIdType to long long occurs?

4

This works

#include "vtkIdTypeArray.h"

  void GetCells(vtkIdType ptId, vtkIdTypeArray* cells);

  void vtkCellLinks::GetCells(vtkIdType ptId, vtkIdTypeArray* cells)
  {
    vtkIdType count = this->Array[ptId].ncells;
    cells->SetNumberOfValues(count);
    cells->SetArray(this->Array[ptId].cells, count, 1);
  }
5

Thanks!

I’ll try to figure out how to incorporate this into my codebase.

Thanks again!

6

The problem is that the original GetCells() method contains no information indicating the size of the array to return. This could be patched in the wrapper code if VTK_SIZEHINT was modified to take a function call.

As a work-around you can paste the code shown above into your VTK source file and rebuild. A new method will be generated in the Java wrapper, so that you can do something like

vtkIdTypeArray cells = new vtkIdTypeArray();
links.GetCells(id, cells);