/// <summary>
/// Sugiyama step 3: Node Ordering
/// This method uses Median heuristic to determine the vertical node
/// order for each layer.
/// </summary>
public void OrderNodes()
{
// Assign temporary vertical indices for further processing
foreach (List<Node> layer in Layers.Skip(1))
{
foreach (Node node in layer)
node.Y = Infinite;
}
foreach (List<Node> layer in Layers.Skip(1))
{
double prevY = -10;
bool layerUpdated = false;
foreach (Node n in layer)
{
// Get the vertical coordinates of each node's right edge
// and get the median from these values
List<Edge> neighborEdges = n.RightEdges
.Where(x => x.EndNode.Y < Infinite).OrderBy(x => x.EndY).ToList();
if (neighborEdges.Count > 1 && neighborEdges.Count % 2 == 0)
{
Edge median1 = neighborEdges[(neighborEdges.Count - 1) / 2];
Edge median2 = neighborEdges[(neighborEdges.Count) / 2];
n.Y = (median1.EndY + median2.EndY -
median1.StartOffsetY - median2.StartOffsetY) / 2;
prevY = n.Y;
layerUpdated = true;
}
else if (neighborEdges.Count > 0)
{
Edge median = neighborEdges[(neighborEdges.Count - 1) / 2];
n.Y = median.EndY - median.StartOffsetY;
prevY = n.Y;
layerUpdated = true;
}
else if (n.LeftEdges.Count > 0 && AnchorRightEdges.Count == 0)
{
n.Y = prevY;
prevY = n.Y;
layerUpdated = true;
}
}
if (layerUpdated)
{
AssignCoordinates(layer);
}
}
// Assign left-anchored nodes
foreach (List<Node> layer in Layers.Skip(1).Reverse())
{
bool layerUpdated = false;
foreach (Node n in layer)
{
if (n.Y >= Infinite)
{
List<Edge> neighborEdges = n.LeftEdges
.Where(x => x.StartNode.Y < Infinite).OrderBy(x => x.EndY).ToList();
if (neighborEdges.Count > 1 && neighborEdges.Count % 2 == 0)
{
Edge median1 = neighborEdges[(neighborEdges.Count - 1) / 2];
Edge median2 = neighborEdges[(neighborEdges.Count) / 2];
n.Y = (median1.StartNode.Y + median1.StartOffsetY +
median2.StartNode.Y + median2.StartOffsetY -
median1.EndOffsetY - median2.EndOffsetY) / 2;
layerUpdated = true;
}
else if (neighborEdges.Count > 0)
{
Edge median = neighborEdges[(neighborEdges.Count - 1) / 2];
n.Y = median.StartNode.Y + median.StartOffsetY - median.EndOffsetY;
layerUpdated = true;
}
}
}
if (layerUpdated)
{
AssignCoordinates(layer);
}
}
}
/// <summary>
/// Adds a new edge to the graph object.
/// </summary>
/// <param name="startId">The guid of the starting node.</param>
/// <param name="endId">The guid of the ending node.</param>
/// <param name="startX">The x coordinate of the connector's left end point.</param>
/// <param name="startY">The y coordinate of the connector's left end point.</param>
/// <param name="endX">The x coordinate of the connector's right end point.</param>
/// <param name="endY">The y coordinate of the connector's right end point.</param>
public void AddEdge(Guid startId, Guid endId, double startX, double startY, double endX, double endY)
{
var edge = new Edge(startId, endId, startX, startY, endX, endY, this);
Edges.Add(edge);
}
