FEM: add ConstraintPython object type

Constraints implemented in python can use this object as their base.
That makes it easier to identify them as constraint objects.

src/Mod/Fem/App/AppFem.cpp

@@ -148,6 +148,7 @@ PyMOD_INIT_FUNC(Fem)
     Fem::FemSetNodesObject          ::init();
 
     Fem::Constraint                 ::init();
+    Fem::ConstraintPython           ::init();
     Fem::ConstraintBearing          ::init();
     Fem::ConstraintFixed            ::init();
     Fem::ConstraintForce            ::init();

src/Mod/Fem/App/FemConstraint.cpp

@@ -54,6 +54,9 @@
 #include "FemConstraint.h"
 #include "FemTools.h"
 
+#include <App/DocumentObjectPy.h>
+#include <App/FeaturePythonPyImp.h>
+
 #include <Mod/Part/App/PartFeature.h>
 #include <Base/Console.h>
 #include <Base/Exception.h>
@@ -391,3 +394,27 @@ const Base::Vector3d Constraint::getDirection(const App::PropertyLinkSub &direct
 
     return Fem::Tools::getDirectionFromShape(sh);
 }
+
+// Python feature ---------------------------------------------------------
+
+namespace App {
+/// @cond DOXERR
+PROPERTY_SOURCE_TEMPLATE(Fem::ConstraintPython, Fem::Constraint)
+template<> const char* Fem::ConstraintPython::getViewProviderName(void) const {
+    return "FemGui::ViewProviderFemConstraintPython";
+}
+
+template<> PyObject* Fem::ConstraintPython::getPyObject(void) {
+    if (PythonObject.is(Py::_None())) {
+        // ref counter is set to 1
+        PythonObject = Py::Object(new App::FeaturePythonPyT<App::DocumentObjectPy>(this),true);
+    }
+    return Py::new_reference_to(PythonObject);
+}
+
+// explicit template instantiation
+template class AppFemExport FeaturePythonT<Fem::Constraint>;
+
+/// @endcond
+
+}

src/Mod/Fem/App/FemConstraint.h

@@ -25,6 +25,7 @@
 #define FEM_CONSTRAINT_H
 
 #include <Base/Vector3D.h>
+#include <App/FeaturePython.h>
 #include <App/DocumentObject.h>
 #include <App/PropertyLinks.h>
 #include <App/PropertyGeo.h>
@@ -75,6 +76,9 @@ protected:
 
 };
 
+typedef App::FeaturePythonT<Constraint> ConstraintPython;
+
+
 } //namespace Fem
 
 

src/Mod/Fem/Gui/AppFemGui.cpp

@@ -120,6 +120,7 @@ PyMOD_INIT_FUNC(FemGui)
     FemGui::ViewProviderSetFaces                  ::init();
     FemGui::ViewProviderSetGeometry               ::init();
     FemGui::ViewProviderFemConstraint             ::init();
+    FemGui::ViewProviderFemConstraintPython       ::init();
     FemGui::ViewProviderFemConstraintBearing      ::init();
     FemGui::ViewProviderFemConstraintFixed        ::init();
     FemGui::ViewProviderFemConstraintForce        ::init();

src/Mod/Fem/Gui/ViewProviderFemConstraint.cpp

@@ -490,3 +490,15 @@ void ViewProviderFemConstraint::checkForWizard()
         wizardSubLayout = wiz->findChild<QVBoxLayout*>(QString::fromLatin1("ShaftWizardLayout"));
     }
 }
+
+
+// Python feature -----------------------------------------------------------------------
+
+namespace Gui {
+/// @cond DOXERR
+PROPERTY_SOURCE_TEMPLATE(FemGui::ViewProviderFemConstraintPython, FemGui::ViewProviderFemConstraint)
+/// @endcond
+
+// explicit template instantiation
+template class FemGuiExport ViewProviderPythonFeatureT<ViewProviderFemConstraint>;
+}

src/Mod/Fem/Gui/ViewProviderFemConstraint.h

@@ -25,6 +25,7 @@
 #define GUI_VIEWPROVIDERFEMCONSTRAINT_H
 
 #include <Gui/ViewProviderGeometryObject.h>
+#include <Gui/ViewProviderPythonFeature.h>
 #include <QObject>
 #include <QVBoxLayout>
 
@@ -117,6 +118,9 @@ protected:
     static QObject* findChildByName(const QObject* parent, const QString& name);
 };
 
+typedef Gui::ViewProviderPythonFeatureT<ViewProviderFemConstraint> ViewProviderFemConstraintPython;
+
+
 } //namespace FemGui