diff --git a/demo/digesttreeviewer.h b/demo/digesttreeviewer.h
new file mode 100644
index 0000000..0f09f67
--- /dev/null
+++ b/demo/digesttreeviewer.h
@@ -0,0 +1,13 @@
+#ifndef DIGESTTREEVIEWER_H
+#define DIGESTTREEVIEWER_H
+#include <QtGui/QGraphicsView>
+
+class DigestTreeViewer : public QGraphicsView
+{ 
+  Q_OBJECT
+
+public:
+  DigestTreeViewer(QWidget *parent = 0);
+};
+
+#endif