fixes based on the feedback: window name prefix is automatically added when it is not there, singleton class returns reference instead of pointer, destructor is private, release function implemented

modules/viz/include/opencv2/viz.hpp

@@ -95,15 +95,18 @@ namespace cv
         class CV_EXPORTS VizAccessor
         {
         public:
-            ~VizAccessor();
-            static VizAccessor * getInstance();
+            static VizAccessor & getInstance();
+            static void release();
             
             Viz3d get(const String &window_name);
             void add(Viz3d window);
             void remove(const String &window_name);
             
+            static void generateWindowName(const String &window_name, String &output);
+            
         private:
             VizAccessor(); // Singleton
+            ~VizAccessor();
             
             static VizAccessor * instance_;
             static bool is_instantiated_;

modules/viz/src/viz.cpp

@@ -95,27 +95,34 @@ cv::viz::VizMap cv::viz::VizAccessor::viz_map_;
 
 cv::viz::VizAccessor::VizAccessor() {}
 
-cv::viz::VizAccessor::~VizAccessor()
-{
-    is_instantiated_ = false;
-}
+cv::viz::VizAccessor::~VizAccessor() {}
 
-cv::viz::VizAccessor * cv::viz::VizAccessor::getInstance()
+cv::viz::VizAccessor & cv::viz::VizAccessor::getInstance()
 {
-    if (is_instantiated_)
+    if (!is_instantiated_)
     {
         instance_ = new VizAccessor();
         is_instantiated_ = true;
     }
-    return instance_;
+    return *instance_;
+}
+
+void cv::viz::VizAccessor::release()
+{
+    if (is_instantiated_)
+    {
+        delete instance_;
+        instance_ = 0;
+        is_instantiated_ = false;
+    }
 }
 
 cv::viz::Viz3d cv::viz::VizAccessor::get(const String & window_name)
 {
     // Add the prefix Viz
-    String name("Viz");
-    name = window_name.empty() ? name : name + " - " + window_name;
-    
+    String name;
+    generateWindowName(window_name, name);
+
     VizMap::iterator vm_itr = viz_map_.find(name);
     bool exists = vm_itr != viz_map_.end();
     if (exists) return vm_itr->second;
@@ -133,13 +140,29 @@ void cv::viz::VizAccessor::add(Viz3d window)
 
 void cv::viz::VizAccessor::remove(const String &window_name)
 {
-    VizMap::iterator vm_itr = viz_map_.find(window_name);
+    // Add the prefix Viz
+    String name;
+    generateWindowName(window_name, name);
+    
+    VizMap::iterator vm_itr = viz_map_.find(name);
     bool exists = vm_itr != viz_map_.end();
     if (!exists) return ;
     viz_map_.erase(vm_itr);
 }
 
+void cv::viz::VizAccessor::generateWindowName(const String &window_name, String &output)
+{
+    output = "Viz";
+    // Already is Viz
+    if (window_name == output) return;
+    
+    String prefixed = output + " - ";
+    if (window_name.substr(0, prefixed.length()) == prefixed) output = window_name; // Already has "Viz - "
+    else if (window_name.substr(0, output.length()) == output) output = prefixed + window_name; // Doesn't have prefix
+    else output = (window_name == "" ? output : prefixed + window_name);
+}
+
 cv::viz::Viz3d cv::viz::get(const String &window_name)
 {
-    return cv::viz::VizAccessor::getInstance()->get(window_name);
+    return cv::viz::VizAccessor::getInstance().get(window_name);
 }

modules/viz/src/viz3d.cpp

@@ -28,7 +28,7 @@ void cv::viz::Viz3d::create(const String &window_name)
     impl_ = new VizImpl(window_name);
     impl_->ref_counter = 1;
     // Register the window
-    cv::viz::VizAccessor::getInstance()->add(*this);
+    cv::viz::VizAccessor::getInstance().add(*this);
 }
 
 void cv::viz::Viz3d::release()
@@ -36,7 +36,7 @@ void cv::viz::Viz3d::release()
     if (impl_ && CV_XADD(&impl_->ref_counter, -1) == 1)
     {
         // Erase the window
-        cv::viz::VizAccessor::getInstance()->remove(getWindowName());
+        cv::viz::VizAccessor::getInstance().remove(getWindowName());
         delete impl_;
         impl_ = 0;
     }

modules/viz/src/viz3d_impl.cpp

@@ -74,9 +74,8 @@ cv::viz::Viz3d::VizImpl::VizImpl (const std::string &name)
 
 
     //////////////////////////////
-
-    String window_name("Viz");
-    window_name = name.empty() ? window_name : window_name + " - " + name;
+    String window_name;
+    VizAccessor::generateWindowName(name, window_name);
     window_->SetWindowName (window_name.c_str ());
 }
 
@@ -85,6 +84,7 @@ cv::viz::Viz3d::VizImpl::~VizImpl ()
 {
     if (interactor_) 
         interactor_->DestroyTimer(timer_id_);
+    if (renderer_) renderer_->Clear();
 }
 
 /////////////////////////////////////////////////////////////////////////////////////////////

modules/viz/src/viz3d_impl.hpp

@@ -69,7 +69,11 @@ public:
     void close ()
     {
         stopped_ = true;
-        interactor_->TerminateApp (); // This tends to close the window...
+        if (interactor_) 
+        {
+            interactor_->GetRenderWindow()->Finalize();
+            interactor_->TerminateApp (); // This tends to close the window...
+        }
     }