How to implement the plugin that support different types of data source

zhe · December 28, 2023, 8:03pm

Hi, dear ParaView experts:

There is a ParaView plugin that works for imageData. I recently updated it and it also work for unstructuredGrid data, could you provide some guidance about how to update the header file and make it work for both imageData and unstructuredData ? Thanks a lot for the help!

My original implementation is as follows (my filter is called vtkUncertainContour):

VTK_ABI_NAMESPACE_BEGIN
class VTKUNCERTAINANALYSISFILTERS_EXPORT vtkUncertainContour : public vtkImageAlgorithm
{
public:
  vtkTypeMacro(vtkUncertainContour, vtkImageAlgorithm);
  void PrintSelf(ostream& os, vtkIndent indent) override;
  static vtkUncertainContour *New();
  ......
  int RequestData(vtkInformation*, vtkInformationVector**, vtkInformationVector*) override;
};

Kenichiro-Yoshimi · December 29, 2023, 5:52am

The filter for both vtkImageData and vtkUnstructuredGrid data should be inherited from vtkDataSetAlgorithm. For example, the vtkGradientFilter may be helpful.

github.com

Kitware/VTK/blob/master/Filters/General/vtkGradientFilter.h

// SPDX-FileCopyrightText: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
// SPDX-FileCopyrightText: Copyright (c) Sandia Corporation
// SPDX-License-Identifier: BSD-3-Clause

/**
 * @class   vtkGradientFilter
 * @brief   A general filter for gradient estimation.
 *
 *
 * This filter estimates the gradient of a field in a data set.  The gradient
 * calculation is dependent on the input dataset type.  The created gradient
 * array is of the same type as the array it is calculated from (e.g. point
 * data or cell data) but the data type will be either float or double.  At
 * the boundary the gradient does not use central differencing.  The output
 * gradient array has 3*number of components of the input data array.  The
 * ordering for the output gradient tuple will be {du/dx, du/dy, du/dz,
 * dv/dx, dv/dy, dv/dz, dw/dx, dw/dy, dw/dz} for an input array {u, v,
 * w}. There are also the options to additionally compute the vorticity and Q
 * criterion of a vector field.  Unstructured grids and polydata can have
 * cells of different dimensions.  To handle different use cases in this

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zhe · December 29, 2023, 3:36pm

Sure, thanks a lot for the information!