refs #452, views upgraded

* load indicator when performing long lasting operations
* custom menu can be injected (->menu delegate)
* resizing based on random elements (subset resized only)

src/blackgui/menudelegate.h

@@ -0,0 +1,39 @@
+/* Copyright (C) 2015
+ * swift project Community / Contributors
+ *
+ * This file is part of swift Project. It is subject to the license terms in the LICENSE file found in the top-level
+ * directory of this distribution and at http://www.swift-project.org/license.html. No part of swift project,
+ * including this file, may be copied, modified, propagated, or distributed except according to the terms
+ * contained in the LICENSE file.
+ */
+
+#ifndef BLACKGUI_MENUDELEGATE_H
+#define BLACKGUI_MENUDELEGATE_H
+
+#include <QMenu>
+#include <QObject>
+
+namespace BlackGui
+{
+    /*!
+     * Interface to implement a custom menu
+     */
+    class IMenuDelegate : public QObject
+    {
+        Q_OBJECT
+
+    public:
+        //! Display custom menu
+        virtual void customMenu(QMenu &menu) const = 0;
+
+        //! Destructor
+        virtual ~IMenuDelegate() {}
+
+    protected:
+        //! Constructor
+        IMenuDelegate(QWidget *parent = nullptr) :  QObject(parent) {}
+    };
+
+} // ns
+
+#endif // guard