public FortuneArc SplitArc(FortuneArc splittingArc, FortuneArc splitter)
{
FortuneArc left = new FortuneArc();
left.Site = splittingArc.Site;
FortuneArc right = new FortuneArc();
right.Site = splittingArc.Site;
// create a new edge
VoronoiEdge edge = new VoronoiEdge(splittingArc.Site.Cell, splitter.Site.Cell);
// both nodes of the edge are initially points at infinity,
// but can become final after the event range
double x = splitter.Site.Cell.DataPoint.X;
double y = splitter.Site.Cell.DataPoint.Y;
double distance = getDistanceToArc(splittingArc.Site.Cell.DataPoint, y, x);
edge.Node1 = new VoronoiNode(x, y - distance);
edge.Node1.IsInfinit = true;
edge.Node2 = new VoronoiNode(x, y - distance);
edge.Node2.IsInfinit = true;
// add this edge in both cell diagram
splitter.Site.Cell.AddEdge(edge);
splittingArc.Site.Cell.AddEdge(edge);
//add nodes to the arcs of the ribs
splitter.LeftNode = edge.Node1;
splitter.RightNode = edge.Node2;
left.LeftNode = splittingArc.LeftNode;
left.RightNode = edge.Node1;
right.LeftNode = edge.Node2;
right.RightNode = splittingArc.RightNode;
left.Left = splittingArc.Left;
right.Right = splittingArc.Right;
splitter.Left = left;
splitter.Right = right;
if (splittingArc.Parent != null)
{
if (splittingArc.Parent.Left == splittingArc)
{
splittingArc.Parent.Left = splitter;
}
else if (splittingArc.Parent.Right == splittingArc)
{
splittingArc.Parent.Right = splitter;
}
}
else
{
Root = splitter;
}
return(splitter);
}
/// <summary>
/// Adds an edge to the cell.
/// </summary>
/// <param name="edge">An edge to add</param>
internal void AddEdge(VoronoiEdge edge)
{
if (edge.Cell1 != this && edge.Cell2 != this)
{
throw new ArgumentException("Edge does not contain a reference to this cell", "edge");
}
_edges.Add(edge);
}
/// <summary>
/// Removes an edge from the cell.
/// </summary>
/// <param name="edge">An edge to remove</param>
internal void RemoveEdge(VoronoiEdge edge)
{
if (_edges.Contains(edge))
{
_edges.Remove(edge);
}
else
{
throw new ArgumentException("Cell does not contain this edge", "edge");
}
}
private void init(List <VoronoiCell> cells, int lastMaxYIndex)
{
_rectangle = new BoundingRectangle();
_eventList = new LinkedList <FortuneEvent>();
_startVerticalNodes = new List <VoronoiNode>();
// Where several points have the minimum ordinate requires a separate pre-treatment
int skipEventCount = 0;
if (lastMaxYIndex > 0)
{
VoronoiNode previousNode = null;
FortuneArc currentArc = null;
skipEventCount = lastMaxYIndex + 1;
for (int i = 0; i <= lastMaxYIndex; i++)
{
// add an arc of coastline
FortuneArc arc = new FortuneArc();
FortuneSite site = new FortuneSite();
site.Cell = cells[i];
arc.Site = site;
if (currentArc != null)
{
currentArc.Right = arc;
}
currentArc = arc;
if (_shoreLine.Root == null)
{
_shoreLine.Root = arc;
}
if (previousNode != null)
{
arc.LeftNode = previousNode;
}
// add the vertical edges of the Voronoi diagram
if (i < lastMaxYIndex)
{
VoronoiEdge edge = new VoronoiEdge(cells[i], cells[i + 1]);
double middleX = (cells[i].DataPoint.X + cells[i + 1].DataPoint.X) / 2;
double middleY = cells[i].DataPoint.Y;
edge.Node1 = new VoronoiNode(middleX, middleY);
edge.Node1.IsInfinit = true;
_startVerticalNodes.Add(edge.Node1);
edge.Node2 = new VoronoiNode(middleX, middleY);
edge.Node2.IsInfinit = true;
previousNode = edge.Node2;
arc.RightNode = edge.Node2;
cells[i].AddEdge(edge);
cells[i + 1].AddEdge(edge);
}
}
}
// fill all point events
int j = 0;
foreach (VoronoiCell cell in cells)
{
if (skipEventCount > j++)
{
continue;
}
FortunePointEvent ev = new FortunePointEvent();
ev.Point = cell.DataPoint;
ev.Cell = cell;
_eventList.AddLast(ev);
}
}
private void handleCircleEvent(FortuneCircleEvent ev)
{
FortuneArc ln = ev.Arc.LeftNeighbor;
FortuneArc rn = ev.Arc.RightNeighbor;
// remove events range associated with this arc
if (ln.CircleEvent != null)
{
_eventList.Remove(ln.CircleEvent);
}
if (rn.CircleEvent != null)
{
_eventList.Remove(rn.CircleEvent);
}
// remove the arc of coastline
_shoreLine.RemoveArc(ev.Arc);
//fix slave nodes arc ribs
if (ev.Arc.LeftNode != null)
{
ev.Arc.LeftNode.Point = ev.CircleCenter;
ev.Arc.LeftNode.IsInfinit = false;
}
if (ev.Arc.RightNode != null)
{
ev.Arc.RightNode.Point = ev.CircleCenter;
ev.Arc.RightNode.IsInfinit = false;
}
// add a new edge
VoronoiEdge edge = new VoronoiEdge(ln.Site.Cell, rn.Site.Cell);
edge.Node1 = new VoronoiNode(ev.CircleCenter.X, ev.CircleCenter.Y);
edge.Node2 = new VoronoiNode((ln.Site.Cell.DataPoint.X + rn.Site.Cell.DataPoint.X) / 2,
(ln.Site.Cell.DataPoint.Y + rn.Site.Cell.DataPoint.Y) / 2);
//expand the bounding rectangle of the chart
_rectangle.Join(ev.CircleCenter);
// one node of the new edge is fixed, the second - no
edge.Node1.IsInfinit = false;
edge.Node2.IsInfinit = true;
// dobavleyaem edge to cells
ln.Site.Cell.AddEdge(edge);
rn.Site.Cell.AddEdge(edge);
//add a triangle in the Delaunay triangulation, if necessary
if (_buildTriangles)
{
_triangles.Add(ev.Triangle);
}
// not a fixed node is a new edge now vanished neighbors arc
ln.RightNode = edge.Node2;
rn.LeftNode = edge.Node2;
FortuneArc lnln = ln.LeftNeighbor;
FortuneArc lnrn = ln.RightNeighbor;
FortuneArc rnln = rn.LeftNeighbor;
FortuneArc rnrn = rn.RightNeighbor;
// add events to the newly formed circle arcs triples
if (lnln != null)
{
if (lnrn != null)
{
FortuneEvent eventToAdd = getCircleEvent(lnln, ln, lnrn, ev.Point.Y);
if (eventToAdd != null)
{
addCircleEvent(eventToAdd);
}
ln.CircleEvent = eventToAdd;
}
}
if (rnln != null)
{
if (rnrn != null)
{
FortuneEvent eventToAdd = getCircleEvent(rnln, rn, rnrn, ev.Point.Y);
if (eventToAdd != null)
{
addCircleEvent(eventToAdd);
}
rn.CircleEvent = eventToAdd;
}
}
}
