/// <summary>
///
/// </summary>
/// <param name="de"></param>
public void ComputeDepths(DirectedEdge de)
{
int edgeIndex = FindIndex(de);
int startDepth = de.GetDepth(Positions.Left);
int targetLastDepth = de.GetDepth(Positions.Right);
// compute the depths from this edge up to the end of the edge array
int nextDepth = ComputeDepths(edgeIndex + 1, edgeList.Count, startDepth);
// compute the depths for the initial part of the array
int lastDepth = ComputeDepths(0, edgeIndex, nextDepth);
if (lastDepth != targetLastDepth)
throw new TopologyException("depth mismatch at " + de.Coordinate);
}
/// <summary>
/// Collect edges from Area inputs which should be in the result but
/// which have not been included in a result area.
/// This happens ONLY:
/// during an intersection when the boundaries of two
/// areas touch in a line segment
/// OR as a result of a dimensional collapse.
/// </summary>
/// <param name="de"></param>
/// <param name="opCode"></param>
/// <param name="edges"></param>
public void CollectBoundaryTouchEdge(DirectedEdge de, SpatialFunctions opCode, IList edges)
{
Label label = de.Label;
if (de.IsLineEdge)
return; // only interested in area edges
if (de.IsVisited)
return; // already processed
if (de.IsInteriorAreaEdge)
return; // added to handle dimensional collapses
if (de.Edge.IsInResult)
return; // if the edge linework is already included, don't include it again
// sanity check for labelling of result edgerings
Assert.IsTrue(!(de.IsInResult || de.Sym.IsInResult) || !de.Edge.IsInResult);
// include the linework if it's in the result of the operation
if (OverlayOp.IsResultOfOp(label, opCode) && opCode == SpatialFunctions.Intersection)
{
edges.Add(de.Edge);
de.VisitedEdge = true;
}
}
/// <summary>
/// Traverse the star of edges, maintaing the current location in the result
/// area at this node (if any).
/// If any L edges are found in the interior of the result, mark them as covered.
/// </summary>
public void FindCoveredLineEdges()
{
// Since edges are stored in CCW order around the node,
// as we move around the ring we move from the right to the left side of the edge
/*
* Find first DirectedEdge of result area (if any).
* The interior of the result is on the RHS of the edge,
* so the start location will be:
* - Interior if the edge is outgoing
* - Exterior if the edge is incoming
*/
Locations startLoc = Locations.Null;
for (IEnumerator it = GetEnumerator(); it.MoveNext();)
{
DirectedEdge nextOut = (DirectedEdge)it.Current;
DirectedEdge nextIn = nextOut.Sym;
if (!nextOut.IsLineEdge)
{
if (nextOut.IsInResult)
{
startLoc = Locations.Interior;
break;
}
if (nextIn.IsInResult)
{
startLoc = Locations.Exterior;
break;
}
}
}
// no A edges found, so can't determine if Curve edges are covered or not
if (startLoc == Locations.Null)
{
return;
}
/*
* move around ring, keeping track of the current location
* (Interior or Exterior) for the result area.
* If Curve edges are found, mark them as covered if they are in the interior
*/
Locations currLoc = startLoc;
for (IEnumerator it = GetEnumerator(); it.MoveNext();)
{
DirectedEdge nextOut = (DirectedEdge)it.Current;
DirectedEdge nextIn = nextOut.Sym;
if (nextOut.IsLineEdge)
{
nextOut.Edge.Covered = (currLoc == Locations.Interior);
}
else
{
// edge is an Area edge
if (nextOut.IsInResult)
{
currLoc = Locations.Exterior;
}
if (nextIn.IsInResult)
{
currLoc = Locations.Interior;
}
}
}
}
/// <summary>
/// Insert a directed edge in the list.
/// </summary>
/// <param name="ee"></param>
public override void Insert(EdgeEnd ee)
{
DirectedEdge de = (DirectedEdge)ee;
InsertEdgeEnd(de, de);
}
/// <summary>
/// Traverse the star of DirectedEdges, linking the included edges together.
/// To link two dirEdges, the next pointer for an incoming dirEdge
/// is set to the next outgoing edge.
/// DirEdges are only linked if:
/// they belong to an area (i.e. they have sides)
/// they are marked as being in the result
/// Edges are linked in CCW order (the order they are stored).
/// This means that rings have their face on the Right
/// (in other words, the topological location of the face is given by the RHS label of the DirectedEdge).
/// PRECONDITION: No pair of dirEdges are both marked as being in the result.
/// </summary>
public void LinkResultDirectedEdges()
{
// make sure edges are copied to resultAreaEdges list
GetResultAreaEdges();
// find first area edge (if any) to start linking at
DirectedEdge firstOut = null;
DirectedEdge incoming = null;
int state = ScanningForIncoming;
// link edges in CCW order
for (int i = 0; i < resultAreaEdgeList.Count; i++)
{
DirectedEdge nextOut = (DirectedEdge)resultAreaEdgeList[i];
DirectedEdge nextIn = nextOut.Sym;
// skip de's that we're not interested in
if (!nextOut.Label.IsArea())
{
continue;
}
// record first outgoing edge, in order to link the last incoming edge
if (firstOut == null && nextOut.IsInResult)
{
firstOut = nextOut;
}
switch (state)
{
case ScanningForIncoming:
if (!nextIn.IsInResult)
{
continue;
}
incoming = nextIn;
state = LinkingToOutgoing;
break;
case LinkingToOutgoing:
if (!nextOut.IsInResult)
{
continue;
}
incoming.Next = nextOut;
state = ScanningForIncoming;
break;
default:
break;
}
}
if (state == LinkingToOutgoing)
{
if (firstOut == null)
{
throw new TopologyException("no outgoing dirEdge found", Coordinate);
}
Assert.IsTrue(firstOut.IsInResult, "unable to link last incoming dirEdge");
incoming.Next = firstOut;
}
}
/// <summary>
///
/// </summary>
private void FindRightmostEdgeAtNode()
{
Node node = minDe.Node;
DirectedEdgeStar star = (DirectedEdgeStar) node.Edges;
minDe = star.GetRightmostEdge();
// the DirectedEdge returned by the previous call is not
// necessarily in the forward direction. Use the sym edge if it isn't.
if (!minDe.IsForward)
{
minDe = minDe.Sym;
minIndex = minDe.Edge.Coordinates.Length - 1;
}
}
/// <summary>
///
/// </summary>
/// <param name="de"></param>
/// <returns></returns>
public override DirectedEdge GetNext(DirectedEdge de)
{
return de.Next;
}
/// <summary>
/// Finds all non-horizontal segments intersecting the stabbing line
/// in the input dirEdge.
/// The stabbing line is the ray to the right of stabbingRayLeftPt.
/// </summary>
/// <param name="stabbingRayLeftPt">The left-hand origin of the stabbing line.</param>
/// <param name="dirEdge"></param>
/// <param name="stabbedSegments">The current list of DepthSegments intersecting the stabbing line.</param>
private void FindStabbedSegments(ICoordinate stabbingRayLeftPt, DirectedEdge dirEdge, IList stabbedSegments)
{
ICoordinate[] pts = dirEdge.Edge.Coordinates;
for (int i = 0; i < pts.Length - 1; i++)
{
seg.P0 = pts[i];
seg.P1 = pts[i + 1];
// ensure segment always points upwards
if (seg.P0.Y > seg.P1.Y)
seg.Reverse();
// skip segment if it is left of the stabbing line
double maxx = Math.Max(seg.P0.X, seg.P1.X);
if (maxx < stabbingRayLeftPt.X) continue;
// skip horizontal segments (there will be a non-horizontal one carrying the same depth info
if (seg.IsHorizontal) continue;
// skip if segment is above or below stabbing line
if (stabbingRayLeftPt.Y < seg.P0.Y || stabbingRayLeftPt.Y > seg.P1.Y) continue;
// skip if stabbing ray is right of the segment
if (CGAlgorithms.ComputeOrientation(seg.P0, seg.P1, stabbingRayLeftPt) == CGAlgorithms.Right) continue;
// stabbing line cuts this segment, so record it
int depth = dirEdge.GetDepth(Positions.Left);
// if segment direction was flipped, use RHS depth instead
if (! seg.P0.Equals(pts[i]))
depth = dirEdge.GetDepth(Positions.Right);
DepthSegment ds = new DepthSegment(seg, depth);
stabbedSegments.Add(ds);
}
}
/// <summary>
///
/// </summary>
/// <param name="de"></param>
private void CopySymDepths(DirectedEdge de)
{
DirectedEdge sym = de.Sym;
sym.SetDepth(Positions.Left, de.GetDepth(Positions.Right));
sym.SetDepth(Positions.Right, de.GetDepth(Positions.Left));
}
/// <summary> /// /// </summary> /// <param name="de"></param> /// <param name="er"></param> public abstract void SetEdgeRing(DirectedEdge de, EdgeRing er);
/// <summary> /// /// </summary> /// <param name="de"></param> /// <returns></returns> public abstract DirectedEdge GetNext(DirectedEdge de);
/// <summary>
/// Add a set of edges to the graph. For each edge two DirectedEdges
/// will be created. DirectedEdges are NOT linked by this method.
/// </summary>
/// <param name="edgesToAdd"></param>
public void AddEdges(IList edgesToAdd)
{
// create all the nodes for the edges
for (IEnumerator it = edgesToAdd.GetEnumerator(); it.MoveNext(); )
{
Edge e = (Edge) it.Current;
edges.Add(e);
DirectedEdge de1 = new DirectedEdge(e, true);
DirectedEdge de2 = new DirectedEdge(e, false);
de1.Sym = de2;
de2.Sym = de1;
Add(de1);
Add(de2);
}
}
/// <summary>
///
/// </summary>
/// <param name="dirEdgeList"></param>
public void FindEdge(IList dirEdgeList)
{
/*
* Check all forward DirectedEdges only. This is still general,
* because each edge has a forward DirectedEdge.
*/
for (IEnumerator i = dirEdgeList.GetEnumerator(); i.MoveNext(); )
{
DirectedEdge de = (DirectedEdge) i.Current;
if (!de.IsForward) continue;
CheckForRightmostCoordinate(de);
}
/*
* If the rightmost point is a node, we need to identify which of
* the incident edges is rightmost.
*/
Assert.IsTrue(minIndex != 0 || minCoord.Equals(minDe.Coordinate), "inconsistency in rightmost processing");
if (minIndex == 0)
FindRightmostEdgeAtNode();
else FindRightmostEdgeAtVertex();
/*
* now check that the extreme side is the R side.
* If not, use the sym instead.
*/
orientedDe = minDe;
Positions rightmostSide = GetRightmostSide(minDe, minIndex);
if (rightmostSide == Positions.Left)
orientedDe = minDe.Sym;
}
/// <summary>
///
/// </summary>
/// <param name="de"></param>
/// <param name="i"></param>
/// <returns></returns>
private Positions GetRightmostSideOfSegment(DirectedEdge de, int i)
{
Edge e = de.Edge;
ICoordinate[] coord = e.Coordinates;
if (i < 0 || i + 1 >= coord.Length)
return Positions.Parallel;
if (coord[i].Y == coord[i + 1].Y)
return Positions.Parallel;
Positions pos = Positions.Left;
if (coord[i].Y < coord[i + 1].Y)
pos = Positions.Right;
return pos;
}
/// <summary>
///
/// </summary>
/// <param name="de"></param>
/// <param name="index"></param>
/// <returns></returns>
private Positions GetRightmostSide(DirectedEdge de, int index)
{
Positions side = GetRightmostSideOfSegment(de, index);
if (side < 0)
side = GetRightmostSideOfSegment(de, index - 1);
if (side < 0)
{
// reaching here can indicate that segment is horizontal
minCoord = null;
CheckForRightmostCoordinate(de);
}
return side;
}
/// <summary>
/// Compute depths for all dirEdges via breadth-first traversal of nodes in graph.
/// </summary>
/// <param name="startEdge">Edge to start processing with.</param>
// <FIX> MD - use iteration & queue rather than recursion, for speed and robustness
private void ComputeDepths(DirectedEdge startEdge)
{
ISet nodesVisited = new HashedSet();
Queue nodeQueue = new Queue();
Node startNode = startEdge.Node;
nodeQueue.Enqueue(startNode);
nodesVisited.Add(startNode);
startEdge.Visited = true;
while (nodeQueue.Count != 0)
{
Node n = (Node) nodeQueue.Dequeue();
nodesVisited.Add(n);
// compute depths around node, starting at this edge since it has depths assigned
ComputeNodeDepth(n);
// add all adjacent nodes to process queue, unless the node has been visited already
IEnumerator i = ((DirectedEdgeStar)n.Edges).GetEnumerator();
while (i.MoveNext())
{
DirectedEdge de = (DirectedEdge) i.Current;
DirectedEdge sym = de.Sym;
if (sym.IsVisited) continue;
Node adjNode = sym.Node;
if (!(nodesVisited.Contains(adjNode)))
{
nodeQueue.Enqueue(adjNode);
nodesVisited.Add(adjNode);
}
}
}
}
/// <summary>
/// Collect all the points from the DirectedEdges of this ring into a contiguous list.
/// </summary>
/// <param name="start"></param>
protected void ComputePoints(DirectedEdge start)
{
startDe = start;
DirectedEdge de = start;
bool isFirstEdge = true;
do
{
Assert.IsTrue(de != null, "found null Directed Edge");
if (de.EdgeRing == this)
throw new TopologyException("Directed Edge visited twice during ring-building at " + de.Coordinate);
edges.Add(de);
Label label = de.Label;
Assert.IsTrue(label.IsArea());
MergeLabel(label);
AddPoints(de.Edge, de.IsForward, isFirstEdge);
isFirstEdge = false;
SetEdgeRing(de, this);
de = GetNext(de);
}
while (de != startDe);
}
/// <summary>
///
/// </summary>
/// <param name="start"></param>
protected void VisitLinkedDirectedEdges(DirectedEdge start)
{
DirectedEdge startDe = start;
DirectedEdge de = start;
do
{
Assert.IsTrue(de != null, "found null Directed Edge");
de.Visited = true;
de = de.Next;
}
while (de != startDe);
}
private EdgeRing shell; // if non-null, the ring is a hole and this EdgeRing is its containing shell
#endregion Fields
#region Constructors
/// <summary>
///
/// </summary>
/// <param name="start"></param>
/// <param name="geometryFactory"></param>
public EdgeRing(DirectedEdge start, IGeometryFactory geometryFactory)
{
this.geometryFactory = geometryFactory;
ComputePoints(start);
ComputeRing();
}
/// <summary>
///
/// </summary>
/// <param name="start"></param>
/// <param name="geometryFactory"></param>
public MaximalEdgeRing(DirectedEdge start, IGeometryFactory geometryFactory)
: base(start, geometryFactory)
{
}
/// <summary>
///
/// </summary>
/// <param name="de"></param>
/// <param name="opCode"></param>
/// <param name="edges"></param>
public void CollectLineEdge(DirectedEdge de, SpatialFunctions opCode, IList edges)
{
Label label = de.Label;
Edge e = de.Edge;
// include Curve edges which are in the result
if (de.IsLineEdge)
{
if (!de.IsVisited && OverlayOp.IsResultOfOp(label, opCode) && !e.IsCovered)
{
edges.Add(e);
de.VisitedEdge = true;
}
}
}
/// <summary>
///
/// </summary>
/// <param name="de"></param>
/// <param name="er"></param>
public override void SetEdgeRing(DirectedEdge de, EdgeRing er)
{
de.EdgeRing = er;
}
/// <summary>
///
/// </summary>
/// <param name="de"></param>
private void CheckForRightmostCoordinate(DirectedEdge de)
{
ICoordinate[] coord = de.Edge.Coordinates;
for (int i = 0; i < coord.Length - 1; i++)
{
// only check vertices which are the start or end point of a non-horizontal segment
// <FIX> MD 19 Sep 03 - NO! we can test all vertices, since the rightmost must have a non-horiz segment adjacent to it
if (minCoord == null || coord[i].X > minCoord.X)
{
minDe = de;
minIndex = i;
minCoord = coord[i];
}
}
}
