ENH: Add Object Event Observer Scripted

- Add vtkMRMLLayerDMObjectEventObserverScripted helper to update
  observers for vtk objects in Python.
- Factorize python binding logic to vtkMRMLLayerDMPythonUtil
- Rename vtkObjectEventObserver for namespace consistency

Author: Thibault-Pelletier

LayerDM/MRMLDM/CMakeLists.txt

@@ -27,6 +27,8 @@ set(${KIT}_SRCS
   vtkMRMLLayerDMInteractionLogic.h
   vtkMRMLLayerDMLayerManager.cxx
   vtkMRMLLayerDMLayerManager.h
+  vtkMRMLLayerDMObjectEventObserver.cxx
+  vtkMRMLLayerDMObjectEventObserver.h
   vtkMRMLLayerDMPipelineCallbackCreator.cxx
   vtkMRMLLayerDMPipelineCallbackCreator.h
   vtkMRMLLayerDMPipelineCreateHelper.h
@@ -39,14 +41,16 @@ set(${KIT}_SRCS
   vtkMRMLLayerDMPipelineManager.cxx
   vtkMRMLLayerDMPipelineManager.h
   vtkMRMLLayerDisplayableManager.h
-  vtkObjectEventObserver.cxx
-  vtkObjectEventObserver.h
 )
 
 if (VTK_WRAP_PYTHON)
   list(APPEND ${KIT}_SRCS
+    vtkMRMLLayerDMObjectEventObserverScripted.cxx
+    vtkMRMLLayerDMObjectEventObserverScripted.h
     vtkMRMLLayerDMPipelineScriptedCreator.cxx
     vtkMRMLLayerDMPipelineScriptedCreator.h
+    vtkMRMLLayerDMPythonUtil.cxx
+    vtkMRMLLayerDMPythonUtil.h
     vtkMRMLLayerDMScriptedPipelineBridge.cxx
     vtkMRMLLayerDMScriptedPipelineBridge.h
   )

LayerDM/MRMLDM/vtkMRMLLayerDMCameraSynchronizer.cxx

@@ -1,7 +1,7 @@
 #include "vtkMRMLLayerDMCameraSynchronizer.h"
 
 // Layer DM includes
-#include "vtkObjectEventObserver.h"
+#include "vtkMRMLLayerDMObjectEventObserver.h"
 
 // Slicer includes
 #include "vtkMRMLAbstractViewNode.h"
@@ -28,7 +28,7 @@ class CameraSynchronizeStrategy
 
 protected:
   vtkSmartPointer<vtkCamera> m_camera;
-  vtkNew<vtkObjectEventObserver> m_eventObserver;
+  vtkNew<vtkMRMLLayerDMObjectEventObserver> m_eventObserver;
 };
 
 class DefaultCameraSynchronizeStrategy : public CameraSynchronizeStrategy

LayerDM/MRMLDM/vtkObjectEventObserver.cxx …DM/vtkMRMLLayerDMObjectEventObserver.cxxLayerDM/MRMLDM/vtkObjectEventObserver.cxx renamed to LayerDM/MRMLDM/vtkMRMLLayerDMObjectEventObserver.cxx LayerDM/MRMLDM/vtkObjectEventObserver.cxx renamed to LayerDM/MRMLDM/vtkMRMLLayerDMObjectEventObserver.cxx

@@ -1,10 +1,10 @@
-#include "vtkObjectEventObserver.h"
+#include "vtkMRMLLayerDMObjectEventObserver.h"
 
 // VTK includes
 #include <vtkCallbackCommand.h>
 #include <vtkObjectFactory.h>
 
-vtkStandardNewMacro(vtkObjectEventObserver);
+vtkStandardNewMacro(vtkMRMLLayerDMObjectEventObserver);
 
 template <class... Ts>
 struct Overloaded : Ts...
@@ -15,14 +15,14 @@ struct Overloaded : Ts...
 template <class... Ts>
 Overloaded(Ts...) -> Overloaded<Ts...>;
 
-vtkObjectEventObserver::vtkObjectEventObserver()
+vtkMRMLLayerDMObjectEventObserver::vtkMRMLLayerDMObjectEventObserver()
   : m_updateCommand(vtkSmartPointer<vtkCallbackCommand>::New())
 {
   this->m_updateCommand->SetClientData(this);
   this->m_updateCommand->SetCallback(
     [](vtkObject* caller, unsigned long eid, void* clientData, void* callData)
     {
-      auto client = static_cast<vtkObjectEventObserver*>(clientData);
+      auto client = static_cast<vtkMRMLLayerDMObjectEventObserver*>(clientData);
       try
       {
         // Dispatch to callback depending on current std variant content
@@ -38,7 +38,7 @@ vtkObjectEventObserver::vtkObjectEventObserver()
     });
 }
 
-vtkObjectEventObserver::~vtkObjectEventObserver()
+vtkMRMLLayerDMObjectEventObserver::~vtkMRMLLayerDMObjectEventObserver()
 {
   for (const auto& obs : m_obsMap)
   {
@@ -52,12 +52,12 @@ vtkObjectEventObserver::~vtkObjectEventObserver()
   }
 }
 
-bool vtkObjectEventObserver::UpdateObserver(vtkObject* prevObj, vtkObject* obj, unsigned long event)
+bool vtkMRMLLayerDMObjectEventObserver::UpdateObserver(vtkObject* prevObj, vtkObject* obj, unsigned long event)
 {
   return this->UpdateObserver(prevObj, obj, std::vector<unsigned long>{ event });
 }
 
-bool vtkObjectEventObserver::UpdateObserver(vtkObject* prevObj, vtkObject* obj, const std::vector<unsigned long>& events)
+bool vtkMRMLLayerDMObjectEventObserver::UpdateObserver(vtkObject* prevObj, vtkObject* obj, const std::vector<unsigned long>& events)
 {
   if (prevObj == obj)
   {
@@ -72,22 +72,22 @@ bool vtkObjectEventObserver::UpdateObserver(vtkObject* prevObj, vtkObject* obj,
   return true;
 }
 
-void vtkObjectEventObserver::SetUpdateCallback(const std::function<void(vtkObject* node)>& callback)
+void vtkMRMLLayerDMObjectEventObserver::SetUpdateCallback(const std::function<void(vtkObject* node)>& callback)
 {
   this->m_callback = callback;
 }
 
-void vtkObjectEventObserver::SetUpdateCallback(const std::function<void(vtkObject* node, unsigned long eventId)>& callback)
+void vtkMRMLLayerDMObjectEventObserver::SetUpdateCallback(const std::function<void(vtkObject* node, unsigned long eventId)>& callback)
 {
   this->m_callback = callback;
 }
 
-void vtkObjectEventObserver::SetUpdateCallback(const std::function<void(vtkObject* node, unsigned long eventId, void* callData)>& callback)
+void vtkMRMLLayerDMObjectEventObserver::SetUpdateCallback(const std::function<void(vtkObject* node, unsigned long eventId, void* callData)>& callback)
 {
   this->m_callback = callback;
 }
 
-void vtkObjectEventObserver::AddObserver(vtkObject* node, unsigned long event)
+void vtkMRMLLayerDMObjectEventObserver::AddObserver(vtkObject* node, unsigned long event)
 {
   if (!node)
   {
@@ -107,7 +107,7 @@ void vtkObjectEventObserver::AddObserver(vtkObject* node, unsigned long event)
   this->m_obsMap[node].insert(node->AddObserver(event, this->m_updateCommand));
 }
 
-void vtkObjectEventObserver::RemoveObserver(vtkObject* node)
+void vtkMRMLLayerDMObjectEventObserver::RemoveObserver(vtkObject* node)
 {
   if (!node || this->m_obsMap.find(node) == std::end(this->m_obsMap))
   {

LayerDM/MRMLDM/vtkObjectEventObserver.h …MLDM/vtkMRMLLayerDMObjectEventObserver.hLayerDM/MRMLDM/vtkObjectEventObserver.h renamed to LayerDM/MRMLDM/vtkMRMLLayerDMObjectEventObserver.h LayerDM/MRMLDM/vtkObjectEventObserver.h renamed to LayerDM/MRMLDM/vtkMRMLLayerDMObjectEventObserver.h

@@ -21,11 +21,11 @@ class vtkCallbackCommand;
 /// Can observe multiple objects and multiple events per object.
 ///
 /// Depending on the callback used, event id and call data can either be forwarded or ignored.
-class VTK_SLICER_LAYERDM_MODULE_MRMLDISPLAYABLEMANAGER_EXPORT vtkObjectEventObserver : public vtkObject
+class VTK_SLICER_LAYERDM_MODULE_MRMLDISPLAYABLEMANAGER_EXPORT vtkMRMLLayerDMObjectEventObserver : public vtkObject
 {
 public:
-  static vtkObjectEventObserver* New();
-  vtkTypeMacro(vtkObjectEventObserver, vtkObject);
+  static vtkMRMLLayerDMObjectEventObserver* New();
+  vtkTypeMacro(vtkMRMLLayerDMObjectEventObserver, vtkObject);
 
   /// @{
   /// Remove previous monitored events from \param prevObj and observe events from the \param obj
@@ -49,8 +49,8 @@ class VTK_SLICER_LAYERDM_MODULE_MRMLDISPLAYABLEMANAGER_EXPORT vtkObjectEventObse
   /// @}
 
 protected:
-  vtkObjectEventObserver();
-  ~vtkObjectEventObserver() override;
+  vtkMRMLLayerDMObjectEventObserver();
+  ~vtkMRMLLayerDMObjectEventObserver() override;
 
 private:
   void AddObserver(vtkObject* obj, unsigned long event);

LayerDM/MRMLDM/vtkMRMLLayerDMObjectEventObserverScripted.cxx

@@ -0,0 +1,37 @@
+#include "vtkMRMLLayerDMObjectEventObserverScripted.h"
+
+#include "vtkMRMLLayerDMPythonUtil.h"
+#include <vtkObjectFactory.h>
+
+vtkStandardNewMacro(vtkMRMLLayerDMObjectEventObserverScripted);
+
+vtkMRMLLayerDMObjectEventObserverScripted::vtkMRMLLayerDMObjectEventObserverScripted()
+  : m_object(nullptr)
+{
+  this->SetUpdateCallback(
+    [this](vtkObject* node, unsigned long eventId, void* callData) -> void
+    {
+      if (!Py_IsInitialized())
+      {
+        return;
+      }
+
+      vtkPythonScopeGilEnsurer gilEnsurer;
+      vtkMRMLLayerDMPythonUtil::CallPythonObject(this->m_object, vtkMRMLLayerDMPythonUtil::ToPyArgs(node, eventId, callData));
+    });
+}
+
+vtkMRMLLayerDMObjectEventObserverScripted::~vtkMRMLLayerDMObjectEventObserverScripted()
+{
+  vtkMRMLLayerDMPythonUtil::DeletePythonObject(&this->m_object);
+}
+
+void vtkMRMLLayerDMObjectEventObserverScripted::SetPythonCallback(PyObject* object)
+{
+  vtkMRMLLayerDMPythonUtil::SetPythonObject(&this->m_object, object);
+}
+
+PyObject* vtkMRMLLayerDMObjectEventObserverScripted::CastCallData(PyObject* object, int vtkType)
+{
+  return vtkMRMLLayerDMPythonUtil::CastCallData(object, vtkType);
+}

LayerDM/MRMLDM/vtkMRMLLayerDMObjectEventObserverScripted.h

@@ -0,0 +1,46 @@
+#pragma once
+
+#include "vtkSlicerLayerDMModuleMRMLDisplayableManagerExport.h"
+
+#include "vtkMRMLLayerDMObjectEventObserver.h"
+
+// VTK includes
+#include <vtkPython.h>
+#include <vtkSmartPyObject.h>
+
+class vtkCallbackCommand;
+
+/// Python lambda implementation of \sa vtkMRMLLayerDMObjectEventObserver
+/// Delegates full callback to underlying Python callable object.
+class VTK_SLICER_LAYERDM_MODULE_MRMLDISPLAYABLEMANAGER_EXPORT vtkMRMLLayerDMObjectEventObserverScripted : public vtkMRMLLayerDMObjectEventObserver
+{
+public:
+  static vtkMRMLLayerDMObjectEventObserverScripted* New();
+  vtkTypeMacro(vtkMRMLLayerDMObjectEventObserverScripted, vtkMRMLLayerDMObjectEventObserver);
+
+  /// \brief Sets the Python callable object to be invoked on events.
+  ///
+  /// The provided Python object should be callable (e.g., a function, lambda,
+  /// or an object with a __call__ method). This callable will be invoked
+  /// whenever the observed event is triggered.
+  ///
+  /// The python callable will be invoked with the following args:
+  ///   (vtkObject* node, unsigned long eventId, void* callData)
+  ///
+  /// If callData is not nullptr, the callData can be converted to the right
+  /// Python type using the \see CastCallData method.
+  void SetPythonCallback(PyObject* object);
+
+  /// \brief Cast call data to appropriate Python type based on VTK type
+  /// \param object Python object to cast
+  /// \param vtkType VTK type identifier to cast to
+  /// \return PyObject* Casted Python object
+  static PyObject* CastCallData(PyObject* object, int vtkType);
+
+protected:
+  vtkMRMLLayerDMObjectEventObserverScripted();
+  ~vtkMRMLLayerDMObjectEventObserverScripted() override;
+
+private:
+  PyObject* m_object;
+};

LayerDM/MRMLDM/vtkMRMLLayerDMPipelineI.cxx

@@ -4,7 +4,7 @@
 #include "vtkMRMLAbstractWidget.h"
 #include "vtkMRMLLayerDMPipelineManager.h"
 #include "vtkMRMLScene.h"
-#include "vtkObjectEventObserver.h"
+#include "vtkMRMLLayerDMObjectEventObserver.h"
 
 // VTK includes
 #include <vtkObjectFactory.h>
@@ -168,7 +168,7 @@ vtkMRMLLayerDMPipelineI::vtkMRMLLayerDMPipelineI()
   , m_displayNode{ nullptr }
   , m_renderer{ nullptr }
   , m_isResetDisplayBlocked{ false }
-  , m_obs(vtkSmartPointer<vtkObjectEventObserver>::New())
+  , m_obs(vtkSmartPointer<vtkMRMLLayerDMObjectEventObserver>::New())
   , m_pipelineManager(nullptr)
 {
   this->m_obs->SetUpdateCallback([this](vtkObject* obj, unsigned long eventId, void* callData) { this->OnUpdate(obj, eventId, callData); });

LayerDM/MRMLDM/vtkMRMLLayerDMPipelineI.h

@@ -16,7 +16,7 @@ class vtkMRMLLayerDMPipelineI;
 class vtkMRMLLayerDMPipelineManager;
 class vtkMRMLNode;
 class vtkMRMLScene;
-class vtkObjectEventObserver;
+class vtkMRMLLayerDMObjectEventObserver;
 class vtkRenderer;
 
 /// \brief Interface for the layered displayable manager pipelines.
@@ -180,7 +180,7 @@ class VTK_SLICER_LAYERDM_MODULE_MRMLDISPLAYABLEMANAGER_EXPORT vtkMRMLLayerDMPipe
   vtkWeakPointer<vtkMRMLNode> m_displayNode;
   vtkWeakPointer<vtkRenderer> m_renderer;
   bool m_isResetDisplayBlocked;
-  vtkSmartPointer<vtkObjectEventObserver> m_obs;
+  vtkSmartPointer<vtkMRMLLayerDMObjectEventObserver> m_obs;
   vtkWeakPointer<vtkMRMLLayerDMPipelineManager> m_pipelineManager;
   vtkWeakPointer<vtkMRMLScene> m_scene;
 };

LayerDM/MRMLDM/vtkMRMLLayerDMPipelineManager.cxx

@@ -6,7 +6,7 @@
 #include "vtkMRMLLayerDMLayerManager.h"
 #include "vtkMRMLLayerDMPipelineFactory.h"
 #include "vtkMRMLLayerDMPipelineI.h"
-#include "vtkObjectEventObserver.h"
+#include "vtkMRMLLayerDMObjectEventObserver.h"
 
 // Slicer includes
 #include "vtkMRMLAbstractViewNode.h"
@@ -178,7 +178,7 @@ vtkMRMLLayerDMPipelineManager::vtkMRMLLayerDMPipelineManager()
   , m_layerManager(vtkSmartPointer<vtkMRMLLayerDMLayerManager>::New())
   , m_cameraSync(vtkSmartPointer<vtkMRMLLayerDMCameraSynchronizer>::New())
   , m_interactionLogic(vtkSmartPointer<vtkMRMLLayerDMInteractionLogic>::New())
-  , m_eventObs(vtkSmartPointer<vtkObjectEventObserver>::New())
+  , m_eventObs(vtkSmartPointer<vtkMRMLLayerDMObjectEventObserver>::New())
   , m_defaultCamera(vtkSmartPointer<vtkCamera>::New())
   , m_viewNode{ nullptr }
   , m_scene{ nullptr }

LayerDM/MRMLDM/vtkMRMLLayerDMPipelineManager.h

@@ -23,11 +23,11 @@ class vtkMRMLLayerDMPipelineFactory;
 class vtkMRMLLayerDMPipelineI;
 class vtkMRMLNode;
 class vtkMRMLScene;
-class vtkObjectEventObserver;
+class vtkMRMLLayerDMObjectEventObserver;
 class vtkRenderWindow;
 class vtkRenderer;
 
-/// @brief Class responsible for handling adding / updating / removing pipelines depending on nodes added / removed /
+/// \brief Class responsible for handling adding / updating / removing pipelines depending on nodes added / removed /
 /// updated in the 3D Slicer Scene.
 ///
 /// The display manager handles connections to the scene's events.
@@ -131,7 +131,7 @@ class VTK_SLICER_LAYERDM_MODULE_MRMLDISPLAYABLEMANAGER_EXPORT vtkMRMLLayerDMPipe
   vtkSmartPointer<vtkMRMLLayerDMLayerManager> m_layerManager;
   vtkSmartPointer<vtkMRMLLayerDMCameraSynchronizer> m_cameraSync;
   vtkSmartPointer<vtkMRMLLayerDMInteractionLogic> m_interactionLogic;
-  vtkSmartPointer<vtkObjectEventObserver> m_eventObs;
+  vtkSmartPointer<vtkMRMLLayerDMObjectEventObserver> m_eventObs;
   vtkSmartPointer<vtkCamera> m_defaultCamera;
 
   vtkWeakPointer<vtkMRMLAbstractViewNode> m_viewNode;