Method FindCell

Common/DataModel/vtkImageData.cxx:357–441

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//------------------------------------------------------------------------------
vtkIdType vtkImageData::FindCell(double x[3], vtkCell* vtkNotUsed(cell),
  vtkIdType vtkNotUsed(cellId), double tol2, int& subId, double pcoords[3], double* weights)
{
  int idx[3];

  // Compute the voxel index
  if (this->ComputeStructuredCoordinates(x, idx, pcoords) == 0)
  {
    // If voxel index is out of bounds, check point "x" against the
    // bounds to see if within tolerance of the bounds.
    const int* extent = this->GetExtent();
    const double* spacing = this->Spacing;

    // Compute squared distance of point x from the boundary
    double dist2 = 0.0;

    for (int i = 0; i < 3; i++)
    {
      int minIdx = extent[i * 2];
      int maxIdx = extent[i * 2 + 1];

      if (idx[i] < minIdx)
      {
        double dist = (idx[i] + pcoords[i] - minIdx) * spacing[i];
        idx[i] = minIdx;
        pcoords[i] = 0.0;
        dist2 += dist * dist;
      }
      else if (idx[i] >= maxIdx)
      {
        double dist = (idx[i] + pcoords[i] - maxIdx) * spacing[i];
        if (maxIdx == minIdx)
        {
          idx[i] = minIdx;
          pcoords[i] = 0.0;
        }
        else
        {
          idx[i] = maxIdx - 1;
          pcoords[i] = 1.0;
        }
        dist2 += dist * dist;
      }
    }

    // Check squared distance against the tolerance
    if (dist2 > tol2)
    {
      return -1;
    }
  }

  if (weights)
  {
    // Shift parametric coordinates for XZ/YZ planes
    int descr = this->GetDataDescription();
    if (descr == vtkStructuredData::VTK_STRUCTURED_XZ_PLANE)
    {