diff --git a/demo/digesttreescene.cpp b/demo/digesttreescene.cpp
new file mode 100644
index 0000000..8d2d5c3
--- /dev/null
+++ b/demo/digesttreescene.cpp
@@ -0,0 +1,97 @@
+#include "digesttreescene.h"
+#include <QtGui>
+#include "ogdf/basic/Array.h"
+#include "ogdf/basic/Graph_d.h"
+#include "ogdf/tree/TreeLayout.h"
+#include <vector>
+#include <iostream>
+#include <assert.h>
+
+static const double Pi = 3.14159265358979323846264338327950288419717;
+static double TwoPi = 2.0 * Pi;
+
+DigestTreeScene::DigestTreeScene(QWidget *parent)
+  : QGraphicsScene(parent)
+{
+  m_graph.clear();
+  std::vector<ogdf::node> v(5);
+  for (int i = 0; i < 5; i++)
+    v[i] = m_graph.newNode();
+
+  m_graph.newEdge(v[0], v[1]);
+  m_graph.newEdge(v[0], v[2]);
+  m_graph.newEdge(v[0], v[3]);
+  m_graph.newEdge(v[0], v[4]);
+
+  ogdf::GraphAttributes GA(m_graph);
+  GA.initAttributes(ogdf::GraphAttributes::nodeLabel);
+  int nodeWidth = 30, nodeHeight = 30, siblingDistance = 60;
+  ogdf::TreeLayout layout;
+  layout.siblingDistance(siblingDistance);
+  layout.rootSelection(ogdf::TreeLayout::rootIsSource);
+  //layout.call(GA);
+  layout.callSortByPositions(GA, m_graph);
+
+  int width = GA.boundingBox().width();
+  std::cout << "GA width " << width << std::endl;
+  int height = GA.boundingBox().height();
+  std::cout << "GA height " << height << std::endl;
+  setSceneRect(QRect(0, 0, width + nodeWidth, height + nodeHeight));
+  GA.setAllWidth(nodeWidth);
+  GA.setAllHeight(nodeHeight);
+
+  ogdf::edge e;
+  forall_edges(e, m_graph) {
+    ogdf::node source = e->source();
+    ogdf::node target = e->target();
+    int x1 = GA.x(source), y1 = -GA.y(source);
+    int x2 = GA.x(target), y2 = -GA.y(target);
+  //  QPainterPath p;
+    QPointF src(x1 + nodeWidth/2, y1 + nodeHeight/2);
+    QPointF dest(x2 + nodeWidth/2, y2 + nodeHeight/2);
+    QLineF line(src, dest);
+    //p.moveTo(x1 + nodeWidth/2, y1 + nodeHeight/2);
+    //p.lineTo(x2 + nodeWidth/2, y2 + nodeHeight/2);
+    //addPath(p, QPen(Qt::black), QBrush(Qt::black));
+    addLine(line, QPen(Qt::black));
+    
+    double angle = ::acos(line.dx() / line.length());
+
+    double arrowSize = 10;
+
+   QPointF sourceArrowP0 = src + QPointF(nodeWidth/2 * line.dx() / line.length(),  nodeHeight/2 * line.dy() / line.length());
+   //QPointF sourceArrowP0 = src + QPointF(cos(angle) * nodeHeight/2, sin(angle) * nodeHeight/2);
+
+   std::cout << "src " << src.x() << ", " << src.y() << std::endl;
+   std::cout << "dest " << dest.x() << ", " << dest.y() << std::endl;
+   std::cout << "line dx " << line.dx() << ", dy " << line.dy() << ", lenght << " << line.length() << std::endl;
+   std::cout << "sap " << sourceArrowP0.x() << ", " << sourceArrowP0.y() << std::endl;
+
+   QPointF sourceArrowP1 = sourceArrowP0 + QPointF(cos(angle + Pi / 3 - Pi/2) * arrowSize,
+                                                    sin(angle + Pi / 3 - Pi/2) * arrowSize);
+      QPointF sourceArrowP2 = sourceArrowP0 + QPointF(cos(angle + Pi - Pi / 3 - Pi/2) * arrowSize,
+                                                         sin(angle + Pi - Pi / 3 - Pi/2) * arrowSize);
+    QLineF line1(sourceArrowP1, sourceArrowP2);
+    addLine(line1, QPen(Qt::black));
+     
+      addPolygon(QPolygonF() << sourceArrowP0<< sourceArrowP1 << sourceArrowP2, QPen(Qt::black), QBrush(Qt::black));
+  }
+
+  /*
+  ogdf::node n;
+  forall_nodes(n, m_graph) {
+    double x = GA.x(n);
+
+    double y = -GA.y(n);
+    double w = GA.width(n);
+    double h = GA.height(n);
+    QRectF boundingRect(x, y, w, h);
+ 
+    addEllipse(boundingRect, QPen(Qt::black), QBrush(Qt::green));
+    QGraphicsTextItem *text = addText(QString(GA.labelNode(n).cstr()));
+    text->setPos(x, y);
+ 
+  }
+    */
+}
+