static IEnumerable<Node> Children(Cluster parent) {
#if SILVERLIGHT
return parent.Clusters.Cast<Node>().Concat(parent.Nodes);
#else
return parent.Clusters.Concat(parent.Nodes);
#endif
}
HashSet<Node> CreateOrGetAddedChildrenOfParent(Cluster parent) {
HashSet<Node> addedChildren;
addedNodesByCluster.TryGetValue(parent, out addedChildren);
if (addedChildren == null)
addedNodesByCluster[parent] = addedChildren = new HashSet<Node>();
return addedChildren;
}
public void IsDescendantOf_BasicTest()
{
Cluster cluster = new Cluster();
Node node = new Node();
Node node2 = new Node();
cluster.AddChild(node);
Assert.IsTrue(node.IsDescendantOf(cluster), "Node is a descendant of cluster but IsDescendantOf returns false.");
Assert.IsFalse(node2.IsDescendantOf(cluster), "Node2 is not a descendant of cluster but IsDescendantOf returns true.");
Assert.IsFalse(cluster.IsDescendantOf(cluster), "A cluster should not be considered a descendant of itself.");
}
static void ProcessAncestorDescendantCouple(Cluster ancestor, Node node, Dictionary<Node, Shape> nodesToShapes) {
Cluster parent=Parent(node);
do {
foreach (var n in Children(parent))
CreateShapeIfNeeeded(n, nodesToShapes);
if (parent == ancestor)
break;
parent = Parent(parent);
} while (true);
CreateShapeIfNeeeded(parent, nodesToShapes);
}
public void IsDescendantOf_ManyParents()
{
Cluster grandMother = new Cluster();
Cluster grandFather = new Cluster();
Cluster parent = new Cluster();
Cluster uncle = new Cluster();
grandMother.AddChild(parent);
grandMother.AddChild(uncle);
grandFather.AddChild(parent);
grandFather.AddChild(uncle);
Node child = new Node();
parent.AddChild(child);
Assert.IsTrue(child.IsDescendantOf(parent), "The child node should be considered a descendant of its parent.");
Assert.IsTrue(child.IsDescendantOf(grandMother), "The child node should be considered a descendant of its grandmother.");
Assert.IsTrue(child.IsDescendantOf(grandFather), "The child node should be considered a descendant of its grandfather.");
Assert.IsFalse(child.IsDescendantOf(uncle), "The child node should not be considered a descendant of its uncle.");
}
/// <summary>
/// Copy the cluster's child Nodes and Clusters as nodes and return a mapping of original to copy.
/// The reverse mapping (copy to original) is available via the copy's UserData
/// </summary>
/// <param name="cluster">Cluster whose contents will be copied</param>
/// <returns>the mapping from original to copy</returns>
internal static Dictionary<Node, Node> ShallowNodeCopyDictionary(Cluster cluster) {
var originalNodeToCopy = new Dictionary<Node, Node>();
foreach (var v in cluster.Nodes)
originalNodeToCopy[v] = new Node(v.BoundaryCurve.Clone()) {UserData = v};
foreach (var cl in cluster.Clusters) {
if (cl.IsCollapsed)
originalNodeToCopy[cl] = new Node(cl.CollapsedBoundary.Clone()) {UserData = cl};
else {
if (cl.BoundaryCurve == null)
cl.BoundaryCurve = cl.RectangularBoundary.RectangularHull();
originalNodeToCopy[cl] = new Node(cl.BoundaryCurve.Clone()) {UserData = cl};
}
}
return originalNodeToCopy;
}
/// <summary>
/// Creates a shallow copy of the root cluster and divides into GeometryGraphs each of which is a connected component with
/// respect to edges internal to root.
/// </summary>
/// <param name="cluster">cluster to break into components</param>
/// <returns>GeometryGraphs that are each a connected component</returns>
static IEnumerable<GeometryGraph> GetComponents(Cluster cluster) {
Dictionary<Node, Node> originalToCopyNodeMap = ShallowNodeCopyDictionary(cluster);
var copiedEdges = new List<Edge>();
foreach (var target in originalToCopyNodeMap.Keys) {
foreach (var e in target.InEdges) {
var sourceAncestorUnderRoot = Ancestor(e.Source, cluster);
if (sourceAncestorUnderRoot == e.Source)
//it is a flat edge and we are only interested in flat edges
copiedEdges.Add(CopyEdge(originalToCopyNodeMap, e, sourceAncestorUnderRoot, target));
}
copiedEdges.AddRange(target.SelfEdges.Select(e => CopyEdge(originalToCopyNodeMap, e)));
}
return GraphConnectedComponents.CreateComponents(originalToCopyNodeMap.Values.ToArray(), copiedEdges);
}
/// <summary>
/// Check if root is an ancestor of node
/// </summary>
/// <param name="node"></param>
/// <param name="root"></param>
/// <returns>true if the node is a descendant of root</returns>
static bool IsDescendant(Node node, Cluster root) {
return Ancestor(node, root) != null;
}
/// <summary>
/// Apply the appropriate layout to the specified cluster and its children (bottom up)
/// </summary>
/// <param name="cluster">the root of the cluster hierarchy to lay out</param>
/// <returns>list of edges external to the cluster</returns>
void LayoutCluster(Cluster cluster) {
if (cluster.IsCollapsed)
return;
LayoutAlgorithmSettings settings = clusterSettings(cluster);
cluster.UnsetInitialLayoutState();
if (runInParallel && cluster.Clusters.Count() > 1)
Parallel.ForEach(cluster.Clusters, parallelOptions, LayoutCluster);
else
foreach (var cl in cluster.Clusters)
LayoutCluster(cl);
List<GeometryGraph> components = (List<GeometryGraph>) GetComponents(cluster);
//currentComponentFraction = (1.0 / clusterCount) / components.Count;
// if (runInParallel)
// Parallel.ForEach(components, parallelOptions, comp => LayoutComponent(settings, comp));
// else // debug!!!!!!
components.ForEach(c => LayoutComponent(settings, c));
var bounds = MdsGraphLayout.PackGraphs(components, settings);
foreach (var g in components)
FixOriginalGraph(g, true);
cluster.UpdateBoundary(bounds);
cluster.SetInitialLayoutState(settings.ClusterMargin);
cluster.RaiseLayoutDoneEvent();
// var l = new List<DebugCurve>();
// foreach (var node in cluster.Nodes) {
// l.Add(new DebugCurve(node.BoundaryCurve));
// }
// foreach (var cl in cluster.AllClustersDepthFirstExcludingSelf()) {
// l.Add(new DebugCurve(cl.BoundaryCurve));
// l.AddRange(cl.Nodes.Select(n=>new DebugCurve(n.BoundaryCurve)));
// }
// LayoutAlgorithmSettings.ShowDebugCurves(l.ToArray());
}
static void FixClusterBoundariesWithNoRectBoundaries(Cluster cluster, double padding) {
foreach (Cluster cl in cluster.Clusters)
FixClusterBoundariesWithNoRectBoundaries(cl, padding);
var box = Rectangle.CreateAnEmptyBox();
var clusterPoints =
cluster.Clusters.SelectMany(c => ClusterPoints(c)).Concat(
cluster.Nodes.SelectMany(n => NodePerimeterPoints(n)));
foreach (var clusterPoint in clusterPoints)
box.Add(clusterPoint);
box.Pad(padding);
cluster.BoundaryCurve = box.Perimeter();
cluster.RectangularBoundary = new RectangularClusterBoundary();
}
/// <summary>
/// Add the parent cluster to this node's list of parents
/// </summary>
/// <param name="parent"></param>
public void AddClusterParent(Cluster parent)
{
ValidateArg.IsNotNull(parent, "parent");
Debug.Assert(parent != this);
clusterParents.Add(parent);
}
Cluster ProcessSubGraphs(Subgraph subgraph) {
var geomCluster = new Cluster(subgraph.Nodes.Select(n => nodeMapping[n]),
subgraph.Subgraphs.Select(ProcessSubGraphs));
foreach (Cluster sub in geomCluster.Clusters)
sub.GeometryParent = geomCluster;
subgraph.GeometryNode = geomCluster;
geomCluster.UserData = subgraph;
nodeMapping[subgraph] = geomCluster;
return geomCluster;
}
void WriteCluster(Cluster cluster, string clusterId) {
WriteStartElement(GeometryToken.Cluster);
WriteAttribute(GeometryToken.Id, clusterId);
WriteAttribute(GeometryToken.Barycenter, cluster.Barycenter);
WriteChildClusters(cluster);
WriteChildNodes(cluster);
if (cluster.BoundaryCurve != null)
WriteICurve(cluster.BoundaryCurve);
WriteClusterRectBoundary(cluster.RectangularBoundary);
WriteEndElement();
}
static IEnumerable<Point> ClusterPoints(Cluster cluster) {
return cluster.BoundaryCurve as Polyline;
}
private void AddOlapClusters(ConstraintGenerator generator, OverlapRemovalCluster olapParentCluster, Cluster incClus, InitialCenterDelegateType nodeCenter)
{
LayoutAlgorithmSettings settings = clusterSettings(incClus);
double nodeSeparationH = settings.NodeSeparation;
double nodeSeparationV = settings.NodeSeparation + 1e-4;
double innerPaddingH = settings.ClusterMargin;
double innerPaddingV = settings.ClusterMargin + 1e-4;
// Creates the OverlapRemoval (Olap) Cluster/Node objects for our FastIncrementalLayout (FIL) objects.
// If !isHorizontal this overwrites the Olap members of the Incremental.Clusters and Msagl.Nodes.
// First create the olapCluster for the current incCluster. If olapParentCluster is null, then
// incCluster is the root of a new hierarchy.
RectangularClusterBoundary rb = incClus.RectangularBoundary;
if (IsHorizontal)
{
rb.olapCluster = generator.AddCluster(
olapParentCluster,
incClus /* userData */,
rb.MinWidth,
rb.MinHeight,
rb.LeftBorderInfo,
rb.RightBorderInfo,
rb.BottomBorderInfo,
rb.TopBorderInfo);
rb.olapCluster.NodePadding = nodeSeparationH;
rb.olapCluster.NodePaddingP = nodeSeparationV;
rb.olapCluster.ClusterPadding = innerPaddingH;
rb.olapCluster.ClusterPaddingP = innerPaddingV;
}
else
{
var postXLeftBorderInfo = new BorderInfo(rb.LeftBorderInfo.InnerMargin, rb.Rect.Left, rb.LeftBorderInfo.Weight);
var postXRightBorderInfo = new BorderInfo(rb.RightBorderInfo.InnerMargin, rb.Rect.Right, rb.RightBorderInfo.Weight);
rb.olapCluster = generator.AddCluster(
olapParentCluster,
incClus /* userData */,
rb.MinHeight,
rb.MinWidth,
rb.BottomBorderInfo,
rb.TopBorderInfo,
postXLeftBorderInfo,
postXRightBorderInfo);
rb.olapCluster.NodePadding = nodeSeparationV;
rb.olapCluster.NodePaddingP = nodeSeparationH;
rb.olapCluster.ClusterPadding = innerPaddingV;
rb.olapCluster.ClusterPaddingP = innerPaddingH;
}
rb.olapCluster.TranslateChildren = rb.GenerateFixedConstraints;
// Note: Incremental.Cluster always creates child List<Cluster|Node> so we don't have to check for null here.
// Add our child nodes.
foreach (var filNode in incClus.Nodes)
{
AddOlapNode(generator, rb.olapCluster, (FiNode)filNode.AlgorithmData, nodeCenter);
}
// Now recurse through all child clusters.
foreach (var incChildClus in incClus.Clusters)
{
AddOlapClusters(generator, rb.olapCluster, incChildClus, nodeCenter);
}
}
public DCluster AddCluster(DCluster parent, string id)
{
if (parent == null)
{
Graph.LayoutAlgorithmSettings = new FastIncrementalLayoutSettings();
Graph.LayoutAlgorithmSettings.EdgeRoutingSettings.KeepOriginalSpline = true;
var settings = Graph.LayoutAlgorithmSettings as FastIncrementalLayoutSettings;
settings.AvoidOverlaps = true;
settings.NodeSeparation = 30;
settings.RouteEdges = true;
}
Subgraph cluster = new Subgraph(id == null ? GetNewNodeID() : id);
Cluster geometryCluster = new Cluster() { GeometryParent = parent == null ? Graph.GeometryGraph : (GeometryObject)parent.GeometryNode };
cluster.GeometryNode = geometryCluster;
geometryCluster.UserData = cluster;
DCluster ret = new DCluster((DObject)parent ?? this, cluster);
cluster.LabelText = null;
SetNodeBoundaryCurve(Graph, cluster);
if (parent == null)
m_RootCluster = ret;
else
parent.AddCluster(ret);
if (UpdateGraphBoundingBoxPreservingCenter())
Invalidate();
AddCluster(ret, false);
return ret;
}
void AddRootCluster(GeometryGraph graph) {
var c = new Cluster(graph.Nodes);
graph.RootCluster = c;
}
static bool Ancestor(Cluster root, Node node)
{
if (node.ClusterParents.Contains(root))
return true;
var parents = new Queue<Cluster>(node.ClusterParents);
while (parents.Count > 0)
{
Cluster parent = parents.Dequeue();
if (root.Clusters.Contains(parent))
return true;
foreach (Cluster grandParent in parent.ClusterParents)
parents.Enqueue(grandParent);
}
return false;
}
static GeometryGraph GenerateGraphWithGroups(Random random, int multiplier)
{
int clusterCount = (2 + random.Next(5))*multiplier;
int nodeCount = (clusterCount + random.Next(20))*multiplier;
int edgeCount = (10 + random.Next(20))*multiplier;
//tree of clusters
var parent = GenerateClusterTree(clusterCount, random);
GeometryGraph graph = new GeometryGraph();
//create nodes
for (int i = 0; i < nodeCount; i++) {
Node node = GraphGenerator.CreateNode(i);
graph.Nodes.Add(node);
}
//create clusters
var clusters = new Cluster[clusterCount];
for (int i = 0; i < clusterCount; i++) {
clusters[i] = new Cluster();
clusters[i].BoundaryCurve = CurveFactory.CreateRectangle(30, 30, new Point(15, 15));
clusters[i].RectangularBoundary = new RectangularClusterBoundary { LeftMargin = 5, RightMargin = 5, BottomMargin = 5, TopMargin = 5 };
}
//set cluster hiearchy
graph.RootCluster = clusters[0];
for (int i = 1; i < clusterCount; i++) {
clusters[parent[i]].AddChild(clusters[i]);
}
//put nodes to clusters
for (int i = 0; i < nodeCount; i++) {
clusters[random.Next(clusterCount)].AddChild(graph.Nodes[i]);
}
for (int i = 0; i < clusterCount; i++) {
if (clusters[i].Nodes.Count() == 0 && clusters[i].Clusters.Count() == 0) {
Node node = GraphGenerator.CreateNode(i);
graph.Nodes.Add(node);
clusters[i].AddChild(node);
nodeCount++;
}
}
//adding edges
for (int i = 0; i < edgeCount; i++) {
int s = random.Next(nodeCount + clusterCount - 1);
Node snode = (s < nodeCount ? graph.Nodes[s] : clusters[s - nodeCount + 1]);
int t = random.Next(nodeCount + clusterCount - 1);
Node tnode = (t < nodeCount ? graph.Nodes[t] : clusters[t - nodeCount + 1]);
if (EdgeIsValid(snode, tnode)) {
var edge = new Edge(snode, tnode);
edge.LineWidth = 0.5 + 3 * random.NextDouble();
graph.Edges.Add(edge);
}
else
i--;
}
SetupPorts(graph);
return graph;
}
/// <summary>
/// find ancestor of node that is immediate child of root, or node itself if node is a direct child of root
/// null if none
/// </summary>
/// <param name="node"></param>
/// <param name="root"></param>
/// <returns>returns highest ancestor of node (or node itself) that is a direct child of root, null if not
/// a descendent of root</returns>
internal static Node Ancestor(Node node, Cluster root) {
if (node.ClusterParents.Contains(root)) return node;
var parents = new Queue<Cluster>(node.ClusterParents);
while (parents.Count > 0) {
Cluster parent = parents.Dequeue();
if (root.Clusters.Contains(parent))
return parent;
foreach (Cluster grandParent in parent.ClusterParents)
parents.Enqueue(grandParent);
}
return null;
}
private void DebugVerifyClusters(ConstraintGenerator generator, Cluster incCluster, Cluster root) {
double dblEpsilon = 0.0001;
// First verify that all nodes are within the cluster.
Rectangle clusRect = incCluster.RectangularBoundary.rectangle;
foreach (var v in incCluster.Nodes) {
FiNode iiFilNode = (FiNode)v.AlgorithmData;
Rectangle iiNodeRect = iiFilNode.mNode.BoundaryCurve.BoundingBox;
if (IsHorizontal) {
// Don't check containment for the root ClusterHierarchy as there is no border for it.
if (incCluster != root) {
// This is horizontal so we've not yet calculated the Y-axis stuff. The only thing we
// can do is verify we're within cluster X bounds. If *Space is negative, there's overlap.
// Generator primary axis is horizontal so use its Padding.
double dblLboundSpace = iiNodeRect.Left - clusRect.Left - generator.Padding;
double dblRboundSpace = clusRect.Right - iiNodeRect.Right - generator.Padding;
Debug.Assert((dblLboundSpace >= -dblEpsilon) && (dblRboundSpace >= -dblEpsilon)
, "Node is not within parent Cluster");
}
} else {
// Don't check containment for the root ClusterHierarchy as there is no border for it.
if (incCluster != root) {
// This is vertical so we've calculated the Y-axis stuff and horizontal is Perpendicular.
DebugVerifyRectContains(clusRect, iiNodeRect
, generator.PaddingP, generator.Padding, dblEpsilon);
}
// Make sure the node doesn't intersect any following nodes, or any clusters.
foreach (var u in incCluster.Nodes) {
if (u == v) continue;
FiNode jjFilNode = (FiNode)u.AlgorithmData;
Rectangle jjNodeRect = jjFilNode.mNode.BoundaryCurve.BoundingBox;
// We've already added the padding for the node so don't add it for the jjNode/Cluster.
DebugVerifyRectsDisjoint(iiNodeRect, jjNodeRect
, generator.PaddingP, generator.Padding, dblEpsilon);
}
foreach (Cluster incClusComp in incCluster.Clusters)
{
DebugVerifyRectsDisjoint(iiNodeRect, incClusComp.RectangularBoundary.rectangle
, generator.PaddingP, generator.Padding, dblEpsilon);
}
} // endif isHorizontal
} // endfor iiNode
// Now verify the clusters are contained and don't overlap.
foreach (var iiIncClus in incCluster.Clusters) {
Rectangle iiClusRect = iiIncClus.RectangularBoundary.rectangle;
if (IsHorizontal) {
// Don't check containment for the root ClusterHierarchy as there is no border for it.
if (incCluster != root) {
// This is horizontal so we've not yet calculated the Y-axis stuff. The only thing we
// can do is verify we're within cluster X bounds. If *Space is negative, there's overlap.
// Generator primary axis is horizontal so use its Padding.
double dblLboundSpace = iiClusRect.Left - clusRect.Left - generator.Padding;
double dblRboundSpace = clusRect.Right - iiClusRect.Right - generator.Padding;
Debug.Assert((dblLboundSpace >= -dblEpsilon) && (dblRboundSpace >= -dblEpsilon)
, "Cluster is not within parent Cluster");
}
} else {
// Don't check containment for the root ClusterHierarchy as there is no border for it.
if (incCluster != root) {
// This is vertical so we've calculated the Y-axis stuff and horizontal is Perpendicular.
DebugVerifyRectContains(clusRect, iiClusRect
, generator.PaddingP, generator.Padding, dblEpsilon);
}
// Make sure the cluster doesn't intersect any following clusters.
foreach (var jjIncClus in incCluster.Clusters) {
if (jjIncClus == iiIncClus) continue;
Rectangle jjClusRect = jjIncClus.RectangularBoundary.rectangle;
DebugVerifyRectsDisjoint(iiClusRect, jjClusRect
, generator.PaddingP, generator.Padding, dblEpsilon);
}
} // endif isHorizontal
// Now recurse.
DebugVerifyClusters(generator, iiIncClus, root);
} // endfor iiCluster
}
void WriteChildClusters(Cluster cluster) {
WriteAttribute(GeometryToken.ChildClusters,
String.Join(" ", cluster.Clusters.Select(child => NodeToIds[child])));
}
private static bool SetOfActiveNodesIsLargerThanThreshold(Cluster ancestor, Node node, Set<Node> usedNodeSet, int threshold) {
Cluster parent = Parent(node);
do {
foreach (var n in Children(parent)) {
usedNodeSet.Insert(n);
if (usedNodeSet.Count > threshold)
return true;
}
if (parent == ancestor)
break;
parent = Parent(parent);
} while (true);
usedNodeSet.Insert(parent);
return usedNodeSet.Count > threshold;
}
void ProcessCluster(Cluster cluster) {
if (cluster.IsCollapsed)
return;
Rectangle oldBounds = cluster.BoundingBox;
cluster.UnsetInitialLayoutStateIncludingAncestors();
LayoutCluster(cluster);
if (cluster != graph.RootCluster) {
Rectangle newBounds = cluster.BoundingBox;
cluster.DeepTranslation(oldBounds.Center - newBounds.Center, true);
}
#if DEBUG
// ValidateLayout(cluster);
#endif
}
void WriteChildNodes(Cluster cluster) {
WriteAttribute(GeometryToken.ChildNodes,
string.Join(" ",
cluster.nodes.Select(child => nodeIds[child].ToString(CultureInfo.InvariantCulture))));
}
static void RouteSimplHooksAndFillTheLists(Cluster rootCluster, List<Edge> inParentEdges,
List<Edge> outParentEdges, EdgeRoutingSettings edgeRoutingSettings) {
var padding = edgeRoutingSettings.Padding + edgeRoutingSettings.PolylinePadding;
foreach (var cluster in rootCluster.AllClustersWidthFirstExcludingSelfAvoidingChildrenOfCollapsed().Where(c=>!c.IsCollapsed)) {
RouteClusterParentInEdges(inParentEdges, edgeRoutingSettings, cluster, padding);
RouteClusterParentOutEdges(outParentEdges, edgeRoutingSettings, cluster, padding);
}
}
void MapClustersToIds(Cluster cluster) {
string id;
var setOfIds = new Set<string>(nodeIds.Values);
foreach (Cluster child in cluster.AllClustersDepthFirst()) {
if (!nodeIds.TryGetValue(child, out id)) {
id = FindNewId(setOfIds);
nodeIds[child] = id;
setOfIds.Insert(id);
}
}
}
static void RouteClusterParentInEdges(List<Edge> inParentEdges, EdgeRoutingSettings edgeRoutingSettings, Cluster cluster,
double padding) {
foreach (var e in cluster.InEdges.Where(e => IsDescendant(e.Source, cluster))) {
double ePadding = Math.Max(padding, 1.5*ArrowlengthAtTarget(e));
var hookPort = e.TargetPort as HookUpAnywhereFromInsidePort;
if (hookPort == null)
e.TargetPort = hookPort = new HookUpAnywhereFromInsidePort(() => cluster.BoundaryCurve);
hookPort.HookSize = ePadding;
e.Curve = StraightLineEdges.CreateLoop(e.Source.BoundingBox, cluster.BoundingBox, ePadding, false);
Arrowheads.TrimSplineAndCalculateArrowheads(e, e.Curve, false,
edgeRoutingSettings.KeepOriginalSpline);
inParentEdges.Add(e);
}
}
/// <summary>
/// Determines if this node is a descendant of the given cluster.
/// </summary>
/// <returns>True if the node is a descendant of the cluster. False otherwise.</returns>
public bool IsDescendantOf(Cluster cluster)
{
Queue<Cluster> parents = new Queue<Cluster>(this.ClusterParents);
while (parents.Count > 0)
{
Cluster parent = parents.Dequeue();
if (parent == cluster)
{
return true;
}
foreach (Cluster grandParent in parent.ClusterParents)
{
parents.Enqueue(grandParent);
}
}
return false;
}
// void CheckEdges() {
// foreach (var edge in graph.Edges)
// CheckEdge(edge);
// }
//
// static void CheckEdge(Edge edge) {
// var s = edge.Source;
// var t = edge.Target;
// var sParents = new Set<Node>(s.ClusterParents);
// var tParents = new Set<Node>(t.ClusterParents);
// if (sParents == tParents) // the edge is between of the nodes of the same cluster, in a simple case
// return;
// var cluster = t as Cluster;
// if (cluster != null && IsDescendant(s, cluster))
// return;
// cluster = s as Cluster;
// if (cluster != null && IsDescendant(t, cluster))
// return;
// Debug.Assert(false, "an edge can be flat or connecting with an ancestor");
// }
/// <summary>
/// Ensures that containment is preserved
/// </summary>
/// <param name="cluster">check is applied to specified cluster and below</param>
static void ValidateLayout(Cluster cluster) {
foreach (var c in cluster.AllClustersDepthFirst())
foreach (var v in c.nodes.Concat(c.Clusters.Cast<Node>()))
Debug.Assert(c.BoundingBox.Contains(v.BoundingBox));
}