chore: adjusted the project directory structure

app/opacityhelper.h

@@ -0,0 +1,23 @@
+#ifndef OPACITYHELPER_H
+#define OPACITYHELPER_H
+
+#include <QWidget>
+
+QT_BEGIN_NAMESPACE
+class QGraphicsOpacityEffect;
+class QPropertyAnimation;
+QT_END_NAMESPACE
+
+class OpacityHelper : QObject
+{
+public:
+    OpacityHelper(QWidget * parent);
+
+    void setOpacity(qreal opacity, bool animated = true);
+
+protected:
+    QGraphicsOpacityEffect * m_opacityFx;
+    QPropertyAnimation * m_opacityAnimation;
+};
+
+#endif // OPACITYHELPER_H