Index: sources/gui/guicontroller.h
===================================================================
diff -u -r5194f3afffb28dac90a7ca4153b6a0ca2f239387 -r9a3ee027dbc33f39ee7df2a9dc5a7897c6b1854d
--- sources/gui/guicontroller.h	(.../guicontroller.h)	(revision 5194f3afffb28dac90a7ca4153b6a0ca2f239387)
+++ sources/gui/guicontroller.h	(.../guicontroller.h)	(revision 9a3ee027dbc33f39ee7df2a9dc5a7897c6b1854d)
@@ -15,38 +15,42 @@
 
 // Qt
 #include <QObject>
-#include <QQuickView>
+
 // Project
+#include "main.h"
 #include "guiactions.h"
 
-#define QML(qml) QStringLiteral("qrc:/" qml ".qml")
+// define
+#define _GuiController GuiController::I()
 
+// namespace
 namespace Gui {
 
 class GuiController : public QObject
 {
     Q_OBJECT
 
-    QQuickView _viewer;
-    void registerView();
-
-    static GuiController *_instance;
-    explicit GuiController(QObject *parent = nullptr);
-
+SINGLETON_DECL(GuiController)
 public:
-    static GuiController *I();
     void init();
 
+private:
+    void connection();
 
-private slots:
-    void onUiStatusChanged(QQuickView::Status vStatus);
-    void actionEvaluation(GuiAction vAction);
+public slots:
+    void doActionRequest (GuiActionType vAction);                      // UI => HD/DG
+    void doActionPerform (GuiActionType vAction, GuiActionInfo vInfo); // UI => HD/DG
 
+private slots: // Should be private for thread safety and is connected internally.
+    void onActionConfirm (GuiActionType vAction, GuiActionInfo vInfo); // UI <= HD/DG
+    void onActionCommand (GuiActionType vAction);                      // UI <= HD/DG
+
 signals:
-    void initialized(bool ok);
+    void didActionRequest(GuiActionType vAction                     ); // UI => HD/DG
+    void didActionConfirm(GuiActionType vAction, GuiActionInfo vInfo); // UI <= HD/DG
 
-    void actionRequested(GuiAction vAction);
-    void actionEvaluated(GuiAction vAction, bool vAccepted);
+    void didActionCommand(GuiActionType vAction                     ); // UI <= HD/DG
+    void didActionPerform(GuiActionType vAction, GuiActionInfo vInfo); // UI => HD/DG
 };
 
 }