private int CountCrossings()
{
// Initialize
foreach (GraphNode node in _graph.Nodes)
{
SpringVertexData data = (SpringVertexData)node.GetData(_SpringVertex);
data.Crossings = 0;
}
foreach (GraphLink link in _graph.Links)
{
SpringEdgeData data = (SpringEdgeData)link.GetData(_SpringEdge);
data.Crossings = 0;
}
foreach (GraphLink link in _graph.Links)
{
CountEdgeCrossings(link);
}
int crossings = 0;
foreach (GraphNode node in _graph.Nodes)
{
SpringVertexData data = (SpringVertexData)node.GetData(_SpringVertex);
crossings += data.Crossings;
}
return(crossings);
}
private GraphNode NodeWithMostCrossings()
{
GraphNode node = null;
int max = 0;
int numLinks = int.MaxValue;
foreach (GraphNode n in _graph.Nodes)
{
SpringVertexData data = (SpringVertexData)n.GetData(_SpringVertex);
if (data.Crossings > max ||
(data.Crossings == max && n.LinkCount < numLinks))
{
node = n;
max = data.Crossings;
numLinks = n.LinkCount;
}
}
return(node);
}
private void CountEdgeCrossings(GraphLink edge)
{
int crossings = 0;
GraphNode v1 = edge.Origin;
GraphNode v2 = edge.Destination;
SpringVertexData v1D = (SpringVertexData)v1.GetData(_SpringVertex);
SpringVertexData v2D = (SpringVertexData)v2.GetData(_SpringVertex);
PointF pt = new PointF(0, 0), pt11, pt12, pt21, pt22;
pt11 = v1.Center;
pt12 = v2.Center;
foreach (GraphLink test in _graph.Links)
{
if (edge == test)
{
continue;
}
pt21 = test.Origin.Center;
pt22 = test.Destination.Center;
if (pt11 != pt21 && pt11 != pt22 && pt12 != pt21 && pt12 != pt22)
{
if (new Line(pt11, pt12).IntersectSegment(pt21, pt22).X !=
float.PositiveInfinity)
{
crossings++;
v1D.Crossings++;
v2D.Crossings++;
}
}
}
SpringEdgeData data = (SpringEdgeData)edge.GetData(_SpringEdge);
data.Crossings = crossings;
}
public bool Arrange(IGraph graph,
SpringLayoutInfo layoutInfo, LayoutProgress progress)
{
_info = layoutInfo;
if (_info.RndSeed != 0)
{
// Use the randomization seed supplied by the user
_r = new Random(_info.RndSeed);
}
// Build the internal graph
_graph = new Graph(graph);
RectangleF rcDoc = CalcContentRect(_graph);
float minNodeX = rcDoc.Left - (50f * _info.NodeDistance);
float minNodeY = rcDoc.Top - (50f * _info.NodeDistance);
float maxNodeX = rcDoc.Right + (50f * _info.NodeDistance);
float maxNodeY = rcDoc.Bottom + (50f * _info.NodeDistance);
// Initialize
foreach (GraphNode node in _graph.Nodes)
{
node.SetData(_SpringVertex, new SpringVertexData());
}
foreach (GraphLink link in _graph.Links)
{
link.SetData(_SpringEdge, new SpringEdgeData());
}
// Calculate vertex radiuses
foreach (GraphNode node in _graph.Nodes)
{
RectangleF rc = node.Bounds;
node.SetData(_VertexRadius,
(double)(rc.Width + rc.Height) / 4);
}
// Update progress
int total = layoutInfo.IterationCount;
float ffactor = total / 100;
int factor = 1;
if (ffactor > 1)
{
factor = (int)Math.Floor((double)ffactor);
total = total / factor + 1;
}
if (progress != null)
{
progress(0, total);
}
// An iterative layout algorithm
for (int step = 1; step <= layoutInfo.IterationCount; step++)
{
// Update progress
if (progress != null)
{
if (step % factor == 0)
{
progress(step / factor, total);
}
}
foreach (GraphNode node in _graph.Nodes)
{
SpringVertexData data = (SpringVertexData)
node.GetData(_SpringVertex);
data.DX /= 4;
data.DY /= 4;
data.EdgeDX = data.EdgeDY = 0;
data.RepulsionDX = data.RepulsionDY = 0;
}
// here the "springs" confine nodes to the desired node distance
foreach (GraphLink link in _graph.Links)
{
// get incident nodes
GraphNode v1 = link.Origin;
GraphNode v2 = link.Destination;
// compute current distance between nodes
PointF v1Pos = v1.Center;
PointF v2Pos = v2.Center;
double vx = v1Pos.X - v2Pos.X;
double vy = v1Pos.Y - v2Pos.Y;
double dist = Math.Sqrt(vx * vx + vy * vy);
dist = (dist == 0) ? 0.0001 : dist;
// get desired distance accomodated for node extents
double desiredDist = _info.NodeDistance;
desiredDist += ((double)v1.GetData(_VertexRadius) +
(double)v2.GetData(_VertexRadius)) / 2;
// now handling cluster center nodes ?
bool masterNodes = _info.EnableClusters &&
(v1.LinkCount > 4 && v2.LinkCount > 4);
desiredDist *= masterNodes ? 4 : link.Link.Weight;
// force factor: optimal length minus actual length,
// is made smaller as the current actual length gets larger.
double f = _ForceConstant * (desiredDist - dist) / dist;
// nodes with few links are moved easier than ones with more
double f1 = masterNodes ? f :
(f * Math.Pow(_stretch / 100.0, v1.LinkCount - 1));
double f2 = masterNodes ? f :
(f * Math.Pow(_stretch / 100.0, v2.LinkCount - 1));
// move first node towards the second one
SpringVertexData v1D = (SpringVertexData)v1.GetData(_SpringVertex);
v1D.EdgeDX += f1 * vx;
v1D.EdgeDY += f1 * vy;
// move second node towards the first one
SpringVertexData v2D = (SpringVertexData)v2.GetData(_SpringVertex);
v2D.EdgeDX += -f2 * vx;
v2D.EdgeDY += -f2 * vy;
}
// here nodes tend to run away one from another
foreach (GraphNode node in _graph.Nodes)
{
SpringVertexData svd = (SpringVertexData)node.GetData(_SpringVertex);
double dx = 0;
double dy = 0;
foreach (GraphNode node2 in _graph.Nodes)
{
if (node2 == node)
{
continue;
}
// now handling cluster center nodes ?
bool masterNodes = _info.EnableClusters &&
(node.LinkCount > 4 && node2.LinkCount > 4);
// if distance is longer than this, ignore repulsion
double intrZone = _info.NodeDistance *
(masterNodes ? 4.5 : _info.RepulsionFactor);
// if distance is shorter than this, randomize node positions
double tooClose = _info.NodeDistance / (masterNodes ? 1 : 5);
// distance to move when using random position
double moveRange = _info.NodeDistance * (masterNodes ? 5 : 1);
// compute current distance between nodes
double vx = node.Center.X - node2.Center.X;
double vy = node.Center.Y - node2.Center.Y;
double distance = vx * vx + vy * vy;
// kind of simmulated annealing, use random jumps for nodes
// that are close one to another; longer jumps for nodes that
// overlap completely and shorter for nodes that don't overlap
if (distance == 0)
{
dx += moveRange / 2 + _r.Next() % ((int)(moveRange * 3));
dy += moveRange / 2 + _r.Next() % ((int)(moveRange * 3));
if (_r.Next() % 2 == 1)
{
dx = -dx;
}
if (_r.Next() % 2 == 1)
{
dy = -dy;
}
}
else if (distance < tooClose * tooClose)
{
dx += moveRange / 2 + _r.Next((int)moveRange);
dy += moveRange / 2 + _r.Next((int)moveRange);
if (_r.Next() % 2 == 1)
{
dx = -dx;
}
if (_r.Next() % 2 == 1)
{
dy = -dy;
}
}
// if nodes are not that close, calculate normal repulsion
else if (distance < intrZone * intrZone)
{
float mf = masterNodes ?
(node.LinkCount + node2.LinkCount) : 1;
dx += mf * vx / (distance * distance);
dy += mf * vy / (distance * distance);
}
}
// apply the summary repulsion of this node with all other nodes
double dlen = dx * dx + dy * dy;
if (dlen > 0)
{
dlen = Math.Sqrt(dlen) / 2;
svd.RepulsionDX += dx / dlen;
svd.RepulsionDY += dy / dlen;
}
}
// sum repulsion and "spring" forces and move nodes
foreach (GraphNode node in _graph.Nodes)
{
// update node movement speed
SpringVertexData vd =
(SpringVertexData)node.GetData(_SpringVertex);
vd.DX += vd.RepulsionDX + vd.EdgeDX;
vd.DY += vd.RepulsionDY + vd.EdgeDY;
// move node
PointF xyd = node.Center;
xyd.X += (float)vd.DX;
xyd.Y += (float)vd.DY;
if (layoutInfo.EnableClusters &&
(((xyd.X < minNodeX) || (xyd.Y < minNodeY)) || ((xyd.X > maxNodeX) || (xyd.Y > maxNodeY))))
{
xyd = node.Center;
vd.DX /= 4;
vd.DY /= 4;
}
node.Center = xyd;
}
// try to decrease crossings if that option is enabled
if (_info.MinimizeCrossings &&
(step % 10 == 0) &&
(step < _info.IterationCount * 2 / 3))
{
int currentCrossings = CountCrossings();
if (currentCrossings > 0)
{
TryDecreaseCrossings(graph.DocRect, _info.NodeDistance, currentCrossings);
}
}
}
// offset the graph to its original location
RectangleF rcDoc2 = CalcContentRect(_graph);
float pdx = rcDoc2.Left - rcDoc.Left;
float pdy = rcDoc2.Top - rcDoc.Top;
foreach (GraphNode node in _graph.Nodes)
{
PointF xyd = node.Center;
xyd.X -= pdx;
xyd.Y -= pdy;
node.Center = xyd;
}
// update flowchart nodes positions
foreach (GraphNode node in _graph.Nodes)
{
node.Node.Bounds = node.Bounds;
}
// call progress delegate
if (progress != null)
{
progress(total, total);
}
return(true);
}
private void TryDecreaseCrossings(RectangleF doc, float ddist, int crossings)
{
GraphNode node = NodeWithMostCrossings();
if (node == null)
{
return;
}
SpringVertexData data = (SpringVertexData)node.GetData(_SpringVertex);
PointF pos = node.Center;
PointF minPos = pos;
for (int c = 3; c >= 1; c--)
{
for (int h = -1; h <= 1; h++)
{
for (int v = -1; v <= 1; v++)
{
if (h == 0 && v == 0)
{
continue;
}
PointF newPos = new PointF(0, 0);
newPos.X = pos.X + c * h * ddist;
newPos.Y = pos.Y + c * v * ddist;
if (newPos.X < doc.Left)
{
continue;
}
if (newPos.X > doc.Right)
{
continue;
}
if (newPos.Y < doc.Top)
{
continue;
}
if (newPos.Y > doc.Bottom)
{
continue;
}
node.Center = newPos;
int newCrossings = CountCrossings();
if (newCrossings < crossings)
{
minPos = newPos;
}
}
}
}
if (minPos != pos)
{
node.Center = minPos;
}
}
