refactor: add override specifier to type_name method in Core/Types.h

Merges all work from andrea-geo branch:
- Geant material management classes
- Serialization enhancements (read-only, NVP/HRP macros)
- Transform/assembly system improvements
- VTK puppet/viewport updates (orthographic toggle, voxel rendering)
- Property grouping, dynamic properties, NotifyPropertiesUpdated
- Object type identification via uLibTypeMacro
- New tests (PropertyGrouping, ReadOnly, vtkQViewport, PuppetParenting)
- Various gcompose UI fixes

Conflict resolved in CMakePresets.json: kept both 'fast' (clang/lld)
and 'mutom' (stub) presets.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitignore

@@ -1,6 +1,7 @@
 CMakeFiles/
-build/
+build*/
 .cache/
+CMakeUserPresets.json
 build_warnings*.log
 final_build.log
 cmake_configure.log
@@ -16,3 +17,4 @@ src/Python/uLib/.nfs*
 test_props.xml
 test_props2.xml
 test_boost.cpp
+.claude/settings.json

CLAUDE.md

@@ -12,7 +12,7 @@ export MAMBA_ROOT_PREFIX="/home/share/micromamba"
 eval "$(/home/share/micromamba/bin/micromamba shell hook --shell bash)"
 micromamba activate mutom
 
-# Configure (from repo root, using Conan preset)
+# Configure (from repo root, using Conan preset — uses Ninja + ccache)
 cmake --preset conan-release
 
 # Build everything
@@ -40,6 +40,18 @@ conan install . --output-folder=build --build=missing
 cmake --preset conan-release
 ```
 
+### Build acceleration (already configured)
+- **Ninja** generator — used automatically via the conan default profile (`~/.conan2/profiles/default`)
+- **ccache** — enabled via `CMAKE_CXX_COMPILER_LAUNCHER=ccache`; cached rebuilds are nearly instant (~0.3s vs ~25s cold)
+- **Clang 22 + lld** profile available (`~/.conan2/profiles/fast`) but blocked by template overload ambiguities in `src/Core/Archives.h` that need fixing for full compatibility
+
+To reconfigure with the fast profile once Archives.h is fixed:
+```bash
+conan install . --output-folder=build --build=missing --profile=fast
+cmake -B build -G Ninja -DCMAKE_TOOLCHAIN_FILE=build/conan_toolchain.cmake -DCMAKE_BUILD_TYPE=Release
+cmake --build build -j$(nproc)
+```
+
 ## Architecture
 
 **uLib** is a C++ framework for Cosmic Muon Tomography (CMT), structured as layered shared libraries:

CMakeLists.txt

@@ -169,6 +169,26 @@ if(Geant4_FOUND)
     add_compile_definitions(HAVE_GEANT4)
     set(HAVE_GEANT4 1)
 
+    # Workaround: Geant4's G4EXPATShim creates EXPAT::EXPAT (uppercase) with
+    # IMPORTED_LOCATION "${EXPAT_LIBRARY}", but EXPAT_LIBRARY is empty when using
+    # conda's config-mode expat package (which installs as expat::expat lowercase).
+    # Resolve the actual library path from expat::expat or via find_library.
+    if(TARGET EXPAT::EXPAT)
+        get_target_property(_expat_loc EXPAT::EXPAT IMPORTED_LOCATION)
+        if(NOT _expat_loc OR _expat_loc MATCHES "NOTFOUND|^$")
+            if(TARGET expat::expat)
+                get_target_property(_expat_loc expat::expat IMPORTED_LOCATION_NOCONFIG)
+            endif()
+            if(NOT _expat_loc OR _expat_loc MATCHES "NOTFOUND|^$")
+                find_library(_expat_loc NAMES expat)
+            endif()
+            if(_expat_loc)
+                set_target_properties(EXPAT::EXPAT PROPERTIES IMPORTED_LOCATION "${_expat_loc}")
+            endif()
+        endif()
+        unset(_expat_loc)
+    endif()
+
     # Sanitize Geant4 targets to remove Qt5 dependencies that conflict with VTK/Qt6
     if(TARGET Geant4::G4interfaces)
         set_target_properties(Geant4::G4interfaces PROPERTIES 

CMakePresets.json

@@ -12,6 +12,22 @@
                 "CMAKE_INSTALL_PREFIX": "${sourceDir}/out/install/${presetName}"
             }
         },
+        {
+            "name": "fast",
+            "displayName": "Fast build: Ninja + clang + ccache",
+            "description": "Uses Ninja generator, clang/lld compiler, and ccache",
+            "generator": "Ninja",
+            "binaryDir": "${sourceDir}/build",
+            "cacheVariables": {
+                "CMAKE_BUILD_TYPE": "Release",
+                "CMAKE_C_COMPILER": "clang",
+                "CMAKE_CXX_COMPILER": "clang++",
+                "CMAKE_EXE_LINKER_FLAGS": "-fuse-ld=lld",
+                "CMAKE_SHARED_LINKER_FLAGS": "-fuse-ld=lld",
+                "CMAKE_CXX_COMPILER_LAUNCHER": "ccache",
+                "CMAKE_C_COMPILER_LAUNCHER": "ccache"
+            }
+        },
         {
             "name": "mutom",
             "description": "",
@@ -19,4 +35,4 @@
             "inherits": []
         }
     ]
-}
+}

CMakeUserPresets.json

@@ -1,9 +0,0 @@
-{
-    "version": 4,
-    "vendor": {
-        "conan": {}
-    },
-    "include": [
-        "build/CMakePresets.json"
-    ]
-}

README.md

@@ -41,7 +41,11 @@ conda activate mutom
 
 ### Configure and Build
 
-1. **Configure Conan profile (if you haven't yet on your machine):**
+#### Standard build (GCC + Ninja + ccache)
+
+The default conan profile uses **Ninja** as the generator and **ccache** for compiler caching, dramatically speeding up incremental rebuilds.
+
+1. **Configure Conan profile (first time only):**
 ```bash
 conan profile detect
 ```
@@ -51,17 +55,39 @@ conan profile detect
 conan install . --output-folder=build --build=missing
 ```
 
-3. **Configure the project with CMake:**
+3. **Configure with CMake:**
 ```bash
 cmake --preset conan-release
 ```
-*(Alternatively: `cd build && cmake .. -DCMAKE_TOOLCHAIN_FILE=conan_toolchain.cmake -DCMAKE_BUILD_TYPE=Release`)*
 
-4. **Build the project:**
+4. **Build:**
 ```bash
-cmake --build build -j10
+cmake --build build -j$(nproc)
 ```
 
+#### LLVM/Clang build (clang + lld + ccache — fastest)
+
+A `fast` conan profile is provided that uses **clang**, **lld** (LLVM linker), and **ccache**. Install them into your environment first:
+
+```bash
+micromamba install -n mutom -y clang clangxx lld -c conda-forge
+```
+
+Then build using the `fast` profile:
+
+```bash
+conan install . --output-folder=build --build=missing --profile=fast
+cmake -B build -G Ninja \
+      -DCMAKE_TOOLCHAIN_FILE=build/conan_toolchain.cmake \
+      -DCMAKE_BUILD_TYPE=Release
+cmake --build build -j$(nproc)
+```
+
+The `fast` profile is defined at `~/.conan2/profiles/fast` and sets:
+- `CMAKE_C_COMPILER=clang` / `CMAKE_CXX_COMPILER=clang++`
+- `CMAKE_EXE_LINKER_FLAGS=-fuse-ld=lld`
+- `CMAKE_CXX_COMPILER_LAUNCHER=ccache`
+
 ### Make python package
 
 ```bash

src/Core/Archives.h

@@ -338,8 +338,6 @@ public:
     }
   }
 
-  using basic_xml_iarchive::load_override;
-
   // Anything not an attribute should be a name value pair as nvp or hrp
   typedef boost::archive::detail::common_iarchive<Archive>
       detail_common_iarchive;
@@ -357,6 +355,9 @@ public:
   // class_name_type can't be handled here as it depends upon the
   // char type used by the stream.  So require the derived implementation.
   // derived in this case is xml_iarchive_impl or base ..
+  // Note: using base::load_override covers all basic_xml_iarchive overloads
+  // transitively, so a separate 'using basic_xml_iarchive::load_override'
+  // is redundant and creates ambiguity with clang.
   using base::load_override;
 
   void load_override(const char *str) {

src/Core/Object.cpp

@@ -121,14 +121,6 @@ void Object::PropertyUpdated() { ULIB_SIGNAL_EMIT(Object::PropertyUpdated); }
 template <class ArchiveT>
 void Object::save_override(ArchiveT &ar, const unsigned int version) {}
 
-// Explicitly instantiate for all uLib archives
-template void Object::serialize(Archive::xml_oarchive &, const unsigned int);
-template void Object::serialize(Archive::xml_iarchive &, const unsigned int);
-template void Object::serialize(Archive::text_oarchive &, const unsigned int);
-template void Object::serialize(Archive::text_iarchive &, const unsigned int);
-template void Object::serialize(Archive::hrt_oarchive &, const unsigned int);
-template void Object::serialize(Archive::hrt_iarchive &, const unsigned int);
-template void Object::serialize(Archive::log_archive &, const unsigned int);
 
 ////////////////////////////////////////////////////////////////////////////////
 ////////////////////////////////////////////////////////////////////////////////

src/Core/Types.h

@@ -182,7 +182,7 @@ typedef bool Bool_t; // Boolean (0=false, 1=true) (bool)
                                                                                \
 public:                                                                        \
   typedef type_info::BaseClass BaseClass;                                      \
-  virtual const char *type_name() const { return type_info::name; }            \
+  virtual const char *type_name() const override { return type_info::name; }            \
   /**/
 
 /**

src/Vtk/Math/vtkVoxImage.cpp

@@ -139,6 +139,7 @@ vtkVoxImage::vtkVoxImage(Content &content)
   GetContent();
   InstallPipe();
   RescaleShaderRange();
+  ULIB_ACTIVATE_DISPLAY_PROPERTIES;
 }
 
 vtkVoxImage::~vtkVoxImage() {
@@ -298,7 +299,7 @@ void vtkVoxImage::SetRepresentation(Representation mode) {
 
 void vtkVoxImage::serialize_display(uLib::Archive::display_properties_archive & ar, const unsigned int version) {
     // Call base class to show Transform and Appearance properties
-    Puppet::serialize_display(ar, version);
+    // Puppet::serialize_display(ar, version);
     
     // Use the member variables for volume rendering parameters
     ar & boost::serialization::make_hrp("Window", m_Window);

src/Vtk/testing/CMakeLists.txt

@@ -4,6 +4,7 @@ set(TESTS
         vtkHandlerWidget
         PuppetPropertyTest
         PuppetParentingTest
+        vtkQViewportTest
         # vtkVoxImageTest
 #	vtkTriangleMeshTest
 )

src/Vtk/testing/vtkQViewportTest.cpp

@@ -0,0 +1,87 @@
+/*//////////////////////////////////////////////////////////////////////////////
+// CMT Cosmic Muon Tomography project //////////////////////////////////////////
+////////////////////////////////////////////////////////////////////////////////
+
+  Copyright (c) 2014, Universita' degli Studi di Padova, INFN sez. di Padova
+  All rights reserved
+
+  Authors: Andrea Rigoni Garola < andrea.rigoni@pd.infn.it >
+
+  ------------------------------------------------------------------
+  This library is free software;  you  can  redistribute  it  and/or
+  modify it  under the  terms  of  the  GNU  Lesser  General  Public
+  License as published  by  the  Free  Software  Foundation;  either
+  version 3.0 of the License, or (at your option) any later version.
+
+  This library 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
+  Lesser General Public License for more details.
+
+  You should have received a copy of  the GNU Lesser General  Public
+  License along with this library.
+
+//////////////////////////////////////////////////////////////////////////////*/
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <QApplication>
+#include <QtGlobal>
+#include <Vtk/vtkQViewport.h>
+
+#include <vtkSmartPointer.h>
+#include <vtkCubeSource.h>
+#include <vtkPolyDataMapper.h>
+#include <vtkActor.h>
+#include <vtkProperty.h>
+#include <vtkRenderer.h>
+
+#include "testing-prototype.h"
+
+using namespace uLib;
+
+int main(int argc, char** argv)
+{
+    // Force X11 on Linux to avoid Wayland connection issues in headless/X11 environments
+#if defined(Q_OS_LINUX)
+    qputenv("QT_QPA_PLATFORM", "xcb");
+#endif
+
+    BEGIN_TESTING(vtk QViewport Test);
+
+    QApplication app(argc, argv);
+    app.processEvents();
+
+    Vtk::QViewport viewport;
+    viewport.resize(800, 600);
+    viewport.show();
+
+    vtkSmartPointer<vtkCubeSource> cube = vtkSmartPointer<vtkCubeSource>::New();
+    cube->SetXLength(10);
+    cube->SetYLength(10);
+    cube->SetZLength(10);
+    cube->Update();
+
+    vtkSmartPointer<vtkPolyDataMapper> mapper = vtkSmartPointer<vtkPolyDataMapper>::New();
+    mapper->SetInputConnection(cube->GetOutputPort());
+    
+    vtkSmartPointer<vtkActor> actor = vtkSmartPointer<vtkActor>::New();
+    actor->SetMapper(mapper);
+    actor->GetProperty()->SetColor(1, 0, 0);
+
+    viewport.addProp(actor);
+    viewport.Render();
+
+    ASSERT_NOT_NULL(viewport.GetRenderWindow());
+    ASSERT_NOT_NULL(viewport.GetRenderer());
+
+    if (std::getenv("CTEST_PROJECT_NAME") == nullptr) {
+        // Run application for a while to see the result
+        return app.exec();
+    }
+    
+
+    END_TESTING;
+}

src/Vtk/uLibVtkViewer.cpp

@@ -72,6 +72,7 @@ struct ViewerData {
   vtkRenderWindow *m_RenderWindow;
   vtkSmartPointer<vtkRenderWindowInteractor> m_Interactor;
   vtkSmartPointer<vtkButtonWidget> m_GridButton;
+  vtkSmartPointer<vtkButtonWidget> m_ProjButton;
 
   ViewerData() : m_RenderWindow(vtkRenderWindow::New()) {}
   ~ViewerData() {
@@ -97,6 +98,11 @@ Viewer::~Viewer() {
       dv->m_GridButton->SetInteractor(nullptr);
       dv->m_GridButton = nullptr;
   }
+  if (dv->m_ProjButton) {
+      dv->m_ProjButton->Off();
+      dv->m_ProjButton->SetInteractor(nullptr);
+      dv->m_ProjButton = nullptr;
+  }
   if (this->GetRenderWindow()) {
       this->GetRenderWindow()->RemoveAllObservers();
   }
@@ -123,6 +129,7 @@ void Viewer::InstallPipe() {
   // Setup native grid button
   if (!std::getenv("CTEST_PROJECT_NAME")) {
       SetupGridButton();
+      SetupProjButton();
   }
 
   // BUT we want to override the style with our custom NoSpin version
@@ -238,9 +245,91 @@ void Viewer::UpdateGridButtonPosition() {
   rep->PlaceWidget(bds);
 }
 
-void Viewer::Start() { 
+void Viewer::SetupProjButton() {
+  if (!dv->m_RenderWindow || !dv->m_RenderWindow->GetInteractor()) return;
+
+  vtkNew<vtkImageCanvasSource2D> canvas;
+  canvas->SetScalarTypeToUnsignedChar();
+  canvas->SetNumberOfScalarComponents(4);
+  canvas->SetExtent(0, 63, 0, 63, 0, 0);
+
+  // State 0: Perspective (gray trapezoid-like lines)
+  canvas->SetDrawColor(0, 0, 0, 0);
+  canvas->FillBox(0, 63, 0, 63);
+  canvas->SetDrawColor(120, 120, 120, 255);
+  canvas->DrawSegment(16, 16, 48, 16);
+  canvas->DrawSegment(48, 16, 56, 48);
+  canvas->DrawSegment(56, 48, 8,  48);
+  canvas->DrawSegment(8,  48, 16, 16);
+  canvas->Update();
+
+  vtkNew<vtkImageData> imgPersp;
+  imgPersp->DeepCopy(canvas->GetOutput());
+
+  // State 1: Orthographic (white rectangle)
+  canvas->SetDrawColor(0, 0, 0, 0);
+  canvas->FillBox(0, 63, 0, 63);
+  canvas->SetDrawColor(255, 255, 255, 255);
+  canvas->DrawSegment(12, 16, 52, 16);
+  canvas->DrawSegment(52, 16, 52, 48);
+  canvas->DrawSegment(52, 48, 12, 48);
+  canvas->DrawSegment(12, 48, 12, 16);
+  canvas->Update();
+
+  vtkNew<vtkImageData> imgOrtho;
+  imgOrtho->DeepCopy(canvas->GetOutput());
+
+  vtkNew<vtkTexturedButtonRepresentation2D> rep;
+  rep->SetNumberOfStates(2);
+  rep->SetButtonTexture(0, imgPersp);
+  rep->SetButtonTexture(1, imgOrtho);
+
+  dv->m_ProjButton = vtkSmartPointer<vtkButtonWidget>::New();
+  dv->m_ProjButton->SetInteractor(dv->m_RenderWindow->GetInteractor());
+  dv->m_ProjButton->SetRepresentation(rep);
+
+  UpdateProjButtonPosition();
+
+  vtkNew<vtkCallbackCommand> resizeCallback;
+  resizeCallback->SetClientData(this);
+  resizeCallback->SetCallback([](vtkObject*, unsigned long, void* clientdata, void*){
+      static_cast<Viewer*>(clientdata)->UpdateProjButtonPosition();
+  });
+  dv->m_RenderWindow->AddObserver(vtkCommand::ModifiedEvent, resizeCallback);
+
+  vtkNew<vtkCallbackCommand> stateCallback;
+  stateCallback->SetClientData(this);
+  stateCallback->SetCallback([](vtkObject* caller, unsigned long, void* clientdata, void*){
+      auto* btn = vtkButtonWidget::SafeDownCast(caller);
+      auto* v = static_cast<Viewer*>(clientdata);
+      auto* r = vtkTexturedButtonRepresentation2D::SafeDownCast(btn->GetRepresentation());
+      v->SetParallelProjection(r->GetState() == 1);
+  });
+  dv->m_ProjButton->AddObserver(vtkCommand::StateChangedEvent, stateCallback);
+  dv->m_ProjButton->On();
+
+  rep->SetState(GetParallelProjection() ? 1 : 0);
+}
+
+void Viewer::UpdateProjButtonPosition() {
+  if (!dv->m_ProjButton || !dv->m_RenderWindow) return;
+  auto* rep = vtkTexturedButtonRepresentation2D::SafeDownCast(dv->m_ProjButton->GetRepresentation());
+  if (!rep) return;
+
+  int *sz = dv->m_RenderWindow->GetSize();
+  if (sz[0] == 0 || sz[1] == 0) return;
+
+  int margin_right = 23;
+  int margin_top = 220; // below the grid button (170 + 50)
+  int btnSz = 100;
+  double bds[6] = { (double)sz[0] - btnSz - margin_right, (double)sz[0] - margin_right,
+                    (double)sz[1] - margin_top  - btnSz/2.0, (double)sz[1] - margin_top + btnSz/2.0, 0, 0 };
+  rep->PlaceWidget(bds);
+}
+
+void Viewer::Start() {
   if (std::getenv("CTEST_PROJECT_NAME")) return;
-  dv->m_RenderWindow->GetInteractor()->Start(); 
+  dv->m_RenderWindow->GetInteractor()->Start();
 }
 
 vtkRenderWindow *Viewer::GetRenderWindow() { return dv->m_RenderWindow; }

src/Vtk/uLibVtkViewer.h

@@ -38,6 +38,9 @@ private:
   void SetupGridButton();
   void UpdateGridButtonPosition();
 
+  void SetupProjButton();
+  void UpdateProjButtonPosition();
+
   struct ViewerData *dv;
 };
 

src/Vtk/vtkQViewport.cpp

@@ -19,6 +19,7 @@ QViewport::QViewport(QWidget* parent)
     , Viewport()
     , m_VtkWidget(nullptr)
     , m_GridButton(nullptr)
+    , m_ProjButton(nullptr)
 {
     // Build the layout – zero margins so VTK fills the entire widget
     auto* layout = new QVBoxLayout(this);
@@ -58,6 +59,36 @@ QViewport::QViewport(QWidget* parent)
     m_GridButton->setChecked(true); // Grid is on by default
     connect(m_GridButton, &QPushButton::clicked, this, &QViewport::onGridButtonClicked);
 
+    // Projection Toggle Button (below grid button)
+    m_ProjButton = new QPushButton(m_VtkWidget);
+    m_ProjButton->setText("P");
+    m_ProjButton->setFixedSize(40, 40);
+    m_ProjButton->setToolTip("Toggle Perspective / Orthographic");
+    m_ProjButton->setStyleSheet(
+        "QPushButton {"
+        "  border-radius: 20px;"
+        "  background-color: rgba(40, 40, 40, 180);"
+        "  color: white;"
+        "  font-size: 22px;"
+        "  border: 1.5px solid rgba(255, 255, 255, 60);"
+        "}"
+        "QPushButton:hover {"
+        "  background-color: rgba(70, 70, 70, 200);"
+        "  border: 1.5px solid rgba(255, 255, 255, 100);"
+        "}"
+        "QPushButton:checked {"
+        "  background-color: rgba(0, 120, 215, 200);"
+        "  color: white;"
+        "  border: 1.5px solid rgba(255, 255, 255, 120);"
+        "}"
+        "QPushButton:pressed {"
+        "  background-color: rgba(0, 90, 160, 220);"
+        "}"
+    );
+    m_ProjButton->setCheckable(true);
+    m_ProjButton->setChecked(false); // Perspective by default
+    connect(m_ProjButton, &QPushButton::clicked, this, &QViewport::onProjButtonClicked);
+
     // After the Qt widget exists but before the first paint,
     // attach the renderer and configure the pipeline.
     SetupPipeline();
@@ -81,7 +112,6 @@ void QViewport::SetupPipeline()
 
 void QViewport::Render()
 {
-    UpdateGrid();
     if (m_VtkWidget && m_VtkWidget->renderWindow())
         m_VtkWidget->renderWindow()->Render();
 }
@@ -101,6 +131,11 @@ void QViewport::onGridButtonClicked()
     SetGridVisible(m_GridButton->isChecked());
 }
 
+void QViewport::onProjButtonClicked()
+{
+    SetParallelProjection(m_ProjButton->isChecked());
+}
+
 void QViewport::OnSelectionChanged(Puppet* p)
 {
     emit puppetSelected(p);
@@ -113,9 +148,14 @@ void QViewport::resizeEvent(QResizeEvent* event)
         // Position under the gizmo (top-right corner).
         // Standard CameraOrientationWidget is usually 150-180px.
         int x = width() - m_GridButton->width() - 10;
-        int y = 160; 
+        int y = 160;
         m_GridButton->move(x, y);
     }
+    if (m_ProjButton) {
+        int x = width() - m_ProjButton->width() - 10;
+        int y = 210;
+        m_ProjButton->move(x, y);
+    }
 }
 
 } // namespace Vtk

src/Vtk/vtkQViewport.h

@@ -51,12 +51,14 @@ protected:
 
 private slots:
     void onGridButtonClicked();
+    void onProjButtonClicked();
 
 private:
     void SetupPipeline();
 
     QVTKOpenGLNativeWidget*             m_VtkWidget;
     QPushButton*                        m_GridButton;
+    QPushButton*                        m_ProjButton;
 };
 
 } // namespace Vtk

src/Vtk/vtkViewport.cpp

@@ -537,6 +537,21 @@ bool Viewport::GetGridVisible() const
     return false;
 }
 
+void Viewport::SetParallelProjection(bool parallel)
+{
+    if (pv->m_Renderer && pv->m_Renderer->GetActiveCamera()) {
+        pv->m_Renderer->GetActiveCamera()->SetParallelProjection(parallel ? 1 : 0);
+        Render();
+    }
+}
+
+bool Viewport::GetParallelProjection() const
+{
+    if (pv->m_Renderer && pv->m_Renderer->GetActiveCamera())
+        return pv->m_Renderer->GetActiveCamera()->GetParallelProjection() != 0;
+    return false;
+}
+
 void Viewport::SetGridAxis(Axis axis)
 {
     m_GridAxis = axis;

src/Vtk/vtkViewport.h

@@ -73,6 +73,10 @@ public:
     void SetGridAxis(Axis axis);
     Axis GetGridAxis() const { return m_GridAxis; }
 
+    // Projection control
+    void SetParallelProjection(bool parallel);
+    bool GetParallelProjection() const;
+
 protected:
     void SetupPipeline(vtkRenderWindowInteractor* iren);