Method ComputeSupportSize

Imaging/Core/vtkImageInterpolator.cxx:72–118

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//------------------------------------------------------------------------------
void vtkImageInterpolator::ComputeSupportSize(const double matrix[16], int size[3])
{
  int s = 1;
  if (this->InterpolationMode == VTK_LINEAR_INTERPOLATION)
  {
    s = 2;
  }
  else if (this->InterpolationMode == VTK_CUBIC_INTERPOLATION)
  {
    s = 4;
  }

  size[0] = s;
  size[1] = s;
  size[2] = s;

  if (matrix == nullptr)
  {
    return;
  }

  // check whether matrix does perspective
  if (matrix[12] != 0 || matrix[13] != 0 || matrix[14] != 0 || matrix[15] != 1.0)
  {
    return;
  }

  // find conditions where matrix maps integers to integer
  for (int i = 0; i < 3; i++)
  {
    int integerRow = 1;
    for (int j = 0; j < 4; j++)
    {
      // verify that the element is an integer
      double x = matrix[4 * i + j];
      // check fraction that remains after floor operation
      double f;
      vtkInterpolationMath::Floor(x, f);
      integerRow &= (f == 0);
    }
    // no extra support required in this direction
    if (integerRow)
    {
      size[i] = 1;
    }
  }
}

//------------------------------------------------------------------------------
void vtkImageInterpolator::InternalDeepCopy(vtkAbstractImageInterpolator* a)