diff --git a/snapshotview.h b/snapshotview.h
--- a/snapshotview.h
+++ b/snapshotview.h
@@ -5,6 +5,7 @@
 #include <QVector>
 #include <QPointF>
 #include <QPen>
+#include <QCloseEvent>
 #include <qwt_plot_curve.h>
 #include "plot.h"
 #include "snapshot.h"
@@ -21,11 +22,15 @@ public:
     explicit SnapShotView(QWidget *parent, SnapShot* snapShot);
     ~SnapShotView();
 
+signals:
+    void closed();
+
 private:
     Ui::SnapShotView *ui;
     QList<QwtPlotCurve*> curves;
 
     SnapShot* _snapShot;
+    void closeEvent(QCloseEvent *event);
 };
 
 #endif // SNAPSHOTVIEW_H