feat: add projection toggle button to switch between perspective and orthographic views

src/Vtk/testing/vtkQViewportTest.cpp

@@ -79,8 +79,9 @@ int main(int argc, char** argv)
 
     if (std::getenv("CTEST_PROJECT_NAME") == nullptr) {
         // Run application for a while to see the result
-        // return app.exec();
+        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();
@@ -100,6 +131,11 @@ void QViewport::onGridButtonClicked()
     SetGridVisible(m_GridButton->isChecked());
 }
 
+void QViewport::onProjButtonClicked()
+{
+    SetParallelProjection(m_ProjButton->isChecked());
+}
+
 void QViewport::OnSelectionChanged(Puppet* p)
 {
     emit puppetSelected(p);
@@ -112,9 +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);