How to Visualize a Custom Graph Layout Using Microsoft Automatic Graph Layout Engine in Diagram for WPF

Convert model from diagram to MSAGL

// Convert model of SfDiagram to MSAGL.
public static GeometryGraph ToMSAGLGraph(this IGraph sfDiagramModel)
{
    // Create a graph.
    GeometryGraph MSAGLmodel = new GeometryGraph();

    foreach (var node in (sfDiagramModel.Nodes as IEnumerable<INode>))
    {
        // Create MSAGL node.
        Microsoft.Msagl.Core.Layout.Node msaglNode = new Microsoft.Msagl.Core.Layout.Node(

            CurveFactory.CreateRectangle(

                // Specify size of a node.
                node.UnitWidth,
                node.UnitHeight,

                // Specify empty position, as layout will take care of positioning.
                new Microsoft.Msagl.Core.Geometry.Point()),

            // Give reference to diagram node.
            node);

        // Add node into MSAGL model.
        MSAGLmodel.Nodes.Add(msaglNode);
    }

    foreach (var con in sfDiagramModel.Connectors as IEnumerable<IConnector>)
    {
        // Create MSAGL connector.
        MSAGLmodel.Edges.Add(
            new Edge(
                // Set source and target by finding MSAGL node based on SfDiagram node.
                MSAGLmodel.FindNodeByUserData(con.SourceNode), 
                MSAGLmodel.FindNodeByUserData(con.TargetNode))
            {
                Weight = 1,
                UserData = con
            });
    }
    return MSAGLmodel;
}

Configure routing technique

Run MSAGL layout and routing

LayoutHelpers.CalculateLayout(graph, settings, null);

Convert model from MSAGL back to diagram

// Sync SfDiagram model based on MSAGL model.
public static void UpdateSfDiagram(this IGraph diagram, GeometryGraph graph)
{
    // Move model to positive axis.
    graph.UpdateBoundingBox();
    graph.Translate(new Microsoft.Msagl.Core.Geometry.Point(-graph.Left, -graph.Bottom));

    // Update node position.
    foreach (var node in graph.Nodes)
    {
        (node.UserData as INode).OffsetX = node.BoundingBox.Center.X;
        (node.UserData as INode).OffsetY = node.BoundingBox.Center.Y;
    }

    // Update connector segments based on routing.
    foreach (var edge in graph.Edges)
    {
        IConnector connector = edge.UserData as IConnector;
        connector.Segments = new ObservableCollection<IConnectorSegment>();
        SyncSegments(connector, edge);
    }
}

// Sync segments of connector.
private static void SyncSegments(IConnector connector, Edge edge)
{
    var segments = connector.Segments as ICollection<IConnectorSegment>;

    // When curve is a line segment.
    if (edge.Curve is LineSegment)
    {
        var line = edge.Curve as LineSegment;
        connector.SourcePoint = new Point(line.Start.X, line.Start.Y);
        segments.Add(new StraightSegment
        {
            Point = new Point(line.Start.X, line.Start.Y)
        });
        segments.Add(new StraightSegment
        {
            Point = new Point(line.End.X, line.End.Y)
        });
    }

    // When curve is a complex segment.
    else if (edge.Curve is Curve)
    {
        Point? pt = null;
        foreach (var segment in (edge.Curve as Curve).Segments)
        {
            // When curve contains a line segment.
            if (segment is LineSegment)
            {
                var line = segment as LineSegment;
                if (pt == null)
                {
                    pt = new Point(line.Start.X, line.Start.Y);
                    segments.Add(new StraightSegment
                    {
                        Point = pt
                    });
                }
                segments.Add(new StraightSegment
                {
                    Point = new Point(line.End.X, line.End.Y)
                });
            }

            // When curve contains a cubic Bezier segment.
            else if (segment is CubicBezierSegment)
            {
                var bezier = segment as CubicBezierSegment;
                pt = new Point(bezier.B(0).X, bezier.B(0).Y);
                if (pt == null)
                {
                    segments.Add(new StraightSegment
                    {
                        Point = pt
                    });
                }
                segments.Add(new CubicCurveSegment
                {
                    Point1 = new Point(bezier.B(1).X, bezier.B(1).Y),
                    Point2 = new Point(bezier.B(2).X, bezier.B(2).Y),
                    Point3 = new Point(bezier.B(3).X, bezier.B(3).Y),
                });
            }

            // When curve contains an arc.
            else if (segment is Ellipse)
            {
                var ellipse = segment as Ellipse;
                var interval = (ellipse.ParEnd - ellipse.ParStart) / 5.0;
                for (var i = ellipse.ParStart;
                            i < ellipse.ParEnd;
                            i += interval)
                {
                    var p = ellipse.Center
                        + (Math.Cos(i) * ellipse.AxisA)
                        + (Math.Sin(i) * ellipse.AxisB);
                    segments.Add(new StraightSegment
                    {
                        Point = new Point(p.X, p.Y)
                    });
                }
            }
            else
            {

            }
        }
        segments.Add(new StraightSegment());
    }
    else
    {

    }
}

Summary