Add a way to ignore dataChanged() calls of the Scene to optimize big selection manipulation.

Use it to make the visibility change of a selection of items instant instead of possibly very long.

Polyhedron/demo/Polyhedron/MainWindow.cpp

@@ -134,6 +134,7 @@ MainWindow::~MainWindow()
 MainWindow::MainWindow(bool verbose, QWidget* parent)
   : CGAL::Qt::DemosMainWindow(parent)
 {
+  bbox_need_update = true;
   ui = new Ui::MainWindow;
   ui->setupUi(this);
   menuBar()->setNativeMenuBar(false);
@@ -207,7 +208,7 @@ MainWindow::MainWindow(bool verbose, QWidget* parent)
           this, SLOT(removeManipulatedFrame(CGAL::Three::Scene_item*)));
 
   connect(scene, SIGNAL(updated_bbox(bool)),
-          this, SLOT(updateViewerBBox(bool)));
+          this, SLOT(invalidate_bbox()));
 
   connect(scene, SIGNAL(selectionChanged(int)),
           this, SLOT(selectSceneItem(int)));
@@ -863,6 +864,8 @@ void MainWindow::error(QString text) {
 
 void MainWindow::updateViewerBBox(bool recenter = true)
 {
+  if(bbox_need_update)
+  {
     const Scene::Bbox bbox = scene->bbox();
     CGAL::qglviewer::Vec center = viewer->camera()->pivotPoint();
     const double xmin = bbox.xmin();
@@ -908,6 +911,8 @@ void MainWindow::updateViewerBBox(bool recenter = true)
     {
       viewer->camera()->setPivotPoint(center);
     }
+    bbox_need_update = false;
+  }
 }
 
 void MainWindow::reloadItem() {
@@ -1644,6 +1649,7 @@ void MainWindow::on_actionLoad_triggered()
         scene->item(scene->numberOfEntries()-1)->setColor(colors_[++nb_item]);
     }
   }
+  updateViewerBBox(true);
 }
 
 void MainWindow::on_actionSaveAs_triggered()
@@ -1817,13 +1823,17 @@ void MainWindow::on_actionDuplicate_triggered()
 
 void MainWindow::on_actionShowHide_triggered()
 {
+  scene->cutDataUpdate(true);
   Q_FOREACH(QModelIndex index, sceneView->selectionModel()->selectedRows())
   {
     int i = scene->getIdFromModelIndex(proxyModel->mapToSource(index));
     CGAL::Three::Scene_item* item = scene->item(i);
     item->setVisible(!item->visible());
-    scene->itemChanged(i);
+    item->redraw();
   }
+  scene->cutDataUpdate(false);
+  scene->allItemsChanged();
+  updateViewerBBox(false);
 }
 
 void MainWindow::on_actionSetPolyhedronA_triggered()
@@ -2407,3 +2417,8 @@ void MainWindow::setDefaultSaveDir()
   QSettings settings;
   settings.setValue("default_saveas_dir", def_save_dir);
 }
+
+void MainWindow::invalidate_bbox()
+{
+  bbox_need_update = true;
+}

Polyhedron/demo/Polyhedron/MainWindow.h

@@ -436,11 +436,13 @@ public:
 public Q_SLOTS:
   void toggleFullScreen();
   void setDefaultSaveDir();
+  void invalidate_bbox();
 private:
   QList<QDockWidget *> visibleDockWidgets;
   QLineEdit operationSearchBar;
   QWidgetAction* searchAction;
   QString def_save_dir;
+  bool bbox_need_update;
 };
 
 #endif // ifndef MAINWINDOW_H

Polyhedron/demo/Polyhedron/Scene.cpp

@@ -42,6 +42,7 @@ Scene::Scene(QObject* parent)
               this, SLOT(adjustIds(Scene_interface::Item_id)));
     picked = false;
     gl_init = false;
+    dont_emit_changes = false;
 
 }
 Scene::Item_id
@@ -1175,6 +1176,8 @@ void Scene::itemChanged()
 
 void Scene::itemChanged(Item_id i)
 {
+  if(dont_emit_changes)
+    return;
     if(i < 0 || i >= m_entries.size())
         return;
 
@@ -1182,7 +1185,14 @@ void Scene::itemChanged(Item_id i)
                      this->createIndex(i, LastColumn));
 }
 
-void Scene::itemChanged(CGAL::Three::Scene_item*)
+void Scene::itemChanged(CGAL::Three::Scene_item*item )
+{
+  if(dont_emit_changes)
+    return;
+  itemChanged(item_id(item));
+}
+
+void Scene::allItemsChanged()
 {
   Q_EMIT dataChanged(this->createIndex(0, 0),
                      this->createIndex(m_entries.size() - 1, LastColumn));

Polyhedron/demo/Polyhedron/Scene.h

@@ -136,6 +136,10 @@ public:
 
   void zoomToPosition(QPoint point,
                         CGAL::Three::Viewer_interface*) Q_DECL_OVERRIDE;
+  void cutDataUpdate(bool b) Q_DECL_OVERRIDE
+  {
+    dont_emit_changes = b;
+  }
   
 public Q_SLOTS:
   //!Specifies a group as Expanded for the Geometric Objects view
@@ -146,6 +150,7 @@ public Q_SLOTS:
   void itemChanged();
   void itemChanged(int i) Q_DECL_OVERRIDE;
   void itemChanged(CGAL::Three::Scene_item*) Q_DECL_OVERRIDE;
+  void allItemsChanged() Q_DECL_OVERRIDE;
   //!Transmits a CGAL::Three::Scene_item::itemVisibilityChanged() signal to the scene.
   void itemVisibilityChanged();
   void itemVisibilityChanged(CGAL::Three::Scene_item*) Q_DECL_OVERRIDE;
@@ -280,6 +285,8 @@ private:
   QOpenGLShaderProgram program;
   QOpenGLVertexArrayObject* vao;
   mutable QOpenGLBuffer vbo[2];
+  //the scene will ignore the itemChanged() signals while this is true. 
+  bool dont_emit_changes;
 
 }; // end class Scene
 

Three/include/CGAL/Three/Scene_interface.h

@@ -144,11 +144,22 @@ public:
   //! Updates the information about `item` in the
   //! Geometric Objects list and redraws the scene.
   virtual void itemChanged(CGAL::Three::Scene_item* item) = 0;
+  //!
+  //! \brief Updates all the items in the SceneView.
+  //!
+  virtual void allItemsChanged() = 0;
   //! Re computes the scene Bbox without recentering it.
   virtual void itemVisibilityChanged(CGAL::Three::Scene_item*) = 0;
   //! Clears the current selection then sets the selected item to the target index.
   //! Used to update the selection in the Geometric Objects view.
   virtual void setSelectedItem(Item_id) = 0;
+  //! \brief ignore data updating.
+  //! 
+  //! This will ignore all the individual calls to `itemChanged()` until 
+  //! `cutDataUpdate()` is called whith `b` being `false`.
+  //! Activate this when you know you will call allItemsChanged() after a loop. 
+  //!
+  virtual void cutDataUpdate(bool b) =0;
 }; // end interface Scene_interface
 }
 }