混合 VTK 和 SWIG Python

Question

这是我的课程：

#include <vtkPolyData>

class VTKUtilities

Mesh3D MeshfromVTKPolyData(vtkPolyData* pdmesh)
{
   Mesh3D mesh;
   //...
   //my conversion code to do the actual conversion
   //...
   return mesh;
}

我尝试通过 SWIG 将其包装为 python 但我尝试像这样在 python 中调用我的函数：

import VTKUtilities
import vtk

pd = vtk.vtkPolyData()
VTKUtilities.MeshfromVTKPolyData(pd)

我收到这样的错误：

NotImplementedError: Wrong number of arguments... for VTKUtilities_MeshfromVTKPolyData
...
Possible prototypes are VTKUtilities::MeshfromVTKPolyData(vtkPolyData *);

我一直在阅读有关类型映射的内容，但我认为我不必搞乱它，因为 SWIG 应该为我处理这个问题？
有人可以告诉我我的流量广告中缺少什么吗？可能需要一些修复吗？

Answer 1

我通过以下方式成功包装了参数为 vtkPolyData 的函数：

首先，您必须在 swig .i 文件中包含 vtkPythonUtil：

%{

#include <vtkPythonUtil.h>

}%

然后，您必须在 swig .i 中映射 vtkPolydata 文件：

 %typemap(out) vtkPolyData* {

    PyImport_ImportModule("vtk");

    $result = vtkPythonUtil::GetObjectFromPointer ( (vtkPolyData*)$1 );
 }

%typemap(in) vtkPolyData* {

    $1 = (vtkPolyData*) vtkPythonUtil::GetPointerFromObject ( $input, "vtkPolyData" );

    if ( $1 == NULL ) { SWIG_fail; }
}

我在 ITK itkVTKGlue 中找到了该文件。

最后，您需要将您的模块与库 vtkPythonCore 链接

Answer 2

这是 vtk.i 为 VTK 的类提供 SWIG 类型映射项目中定义的类的内存管理挂钩，这些类派生自 SWIG 包装的 VTK 对象。

这里的代码

是完整的代码。这是使用 VTK 8 和 SWIG 3.7 进行测试的。请注意，上述链接包含示例，并且可能包含未来的更新。

/*
vtk.i a SWIG interface to VTK classes
Copyright (C)  2017 Burlen Loring

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/
%{
#include <vtkPythonUtil.h>
%}

%include "exception.i"

/*---------------------------------------------------------------------------
macro: VTK_SWIG_INTEROP(vtk_t)

arguments:
  vtk_t - a VTK class name that is used in the SWIG generated API.

The macro defines the typemaps needed for SWIG to convert to and
from VTK's Python bindings. Use this when your API containes pointers
to classes defined in VTK.
---------------------------------------------------------------------------*/
%define VTK_SWIG_INTEROP(vtk_t)
%{
#include <vtk_t##.h>
%}
%typemap(out) vtk_t*
{
  $result = vtkPythonUtil::GetObjectFromPointer(
    static_cast<vtkObjectBase*>($1));
}
%typemap(in) vtk_t*
{
  $1 = static_cast<vtk_t*>(
    vtkPythonUtil::GetPointerFromObject($input,#vtk_t));
  if (!$1)
  {
    SWIG_exception(SWIG_TypeError,
      "an object of type " #vtk_t " is required");
  }
}
%typemap(typecheck, precedence=SWIG_TYPECHECK_POINTER) vtk_t*
{
  $1 = vtkPythonUtil::GetPointerFromObject($input,#vtk_t) ? 1 : 0;
}
%enddef

/*---------------------------------------------------------------------------
macro: VTK_DERIVED(derived_t)

arguments:
  derived_t - name of a class that derives from vtkObjectBase.

The macro causes SWIG to wrap the class and defines memory management hooks
that prevent memory leaks when SWIG creates the objects. Use this to wrap
VTK classes defined in your project.
---------------------------------------------------------------------------*/
%define VTK_DERIVED(derived_t)
%{
#include <derived_t##.h>
%}
%feature("ref") derived_t "$this->Register(nullptr);"
%feature("unref") derived_t "$this->UnRegister(nullptr);"
%newobject derived_t##::New();
%include <derived_t##.h>
%enddef

如果您的 API 使用 vtkObjectBase 和 vtkDataObject，您的 SWIG .i 文件将包括：

VTK_SWIG_INTEROP(vtkObjectBase)
VTK_SWIG_INTEROP(vtkDataObject)

您的 API 中将出现每个 VTK 类一个宏调用。

用法示例

如果您定义一个从 vtkObject 派生的类或其名为 DataAdaptor 的子类之一，您的 SWIG .i 文件将包括：

VTK_DERIVED(DataAdaptor)

请注意，您还需要为您的类 API 中的任何 VTK 类（包括 vtkObjectBase）调用 VTK_SWIG_INTEROP。