/// <summary>
/// Create a new "split edge" with the section of points between
/// (and including) the two intersections.
/// The label for the new edge is the same as the label for the parent edge.
/// </summary>
/// <param name="ei0"></param>
/// <param name="ei1"></param>
public Edge CreateSplitEdge(EdgeIntersection ei0, EdgeIntersection ei1)
{
int npts = ei1.SegmentIndex - ei0.SegmentIndex + 2;
var lastSegStartPt = edge.Points[ei1.SegmentIndex];
// if the last intersection point is not equal to the its segment start pt,
// add it to the points list as well.
// (This check is needed because the distance metric is not totally reliable!)
// The check for point equality is 2D only - Z values are ignored
bool useIntPt1 = ei1.Distance > 0.0 || !ei1.Coordinate.Equals2D(lastSegStartPt);
if (!useIntPt1)
{
npts--;
}
var pts = new Coordinate[npts];
int ipt = 0;
pts[ipt++] = ei0.Coordinate.Copy();
for (int i = ei0.SegmentIndex + 1; i <= ei1.SegmentIndex; i++)
{
pts[ipt++] = edge.Points[i];
}
if (useIntPt1)
{
pts[ipt] = ei1.Coordinate;
}
return(new Edge(pts, new Label(edge.Label)));
}
/// <summary>
///
/// </summary>
/// <param name="outstream"></param>
public void Write(StreamWriter outstream)
{
outstream.WriteLine("Intersections:");
for (IEnumerator <EdgeIntersection> it = GetEnumerator(); it.MoveNext();)
{
EdgeIntersection ei = it.Current;
ei.Write(outstream);
}
}
/// <summary>
/// Adds an intersection into the list, if it isn't already there.
/// The input segmentIndex and dist are expected to be normalized.
/// </summary>
/// <param name="intPt"></param>
/// <param name="segmentIndex"></param>
/// <param name="dist"></param>
/// <returns>The EdgeIntersection found or added.</returns>
public EdgeIntersection Add(Coordinate intPt, int segmentIndex, double dist)
{
EdgeIntersection eiNew = new EdgeIntersection(intPt, segmentIndex, dist);
EdgeIntersection ei;
if (nodeMap.TryGetValue(eiNew, out ei))
return ei;
nodeMap[eiNew] = eiNew;
return eiNew;
}
/// <summary>
/// Adds an intersection into the list, if it isn't already there.
/// The input segmentIndex and dist are expected to be normalized.
/// </summary>
/// <param name="intPt"></param>
/// <param name="segmentIndex"></param>
/// <param name="dist"></param>
/// <returns>The EdgeIntersection found or added.</returns>
public EdgeIntersection Add(Coordinate intPt, int segmentIndex, double dist)
{
var eiNew = new EdgeIntersection(intPt, segmentIndex, dist);
EdgeIntersection ei;
if (nodeMap.TryGetValue(eiNew, out ei))
{
return(ei);
}
nodeMap[eiNew] = eiNew;
return(eiNew);
}
/// <summary>
/// Create a StubEdge for the edge after the intersection eiCurr.
/// The next intersection is provided
/// in case it is the endpoint for the stub edge.
/// Otherwise, the next point from the parent edge will be the endpoint.
/// eiCurr will always be an EdgeIntersection, but eiNext may be null.
/// </summary>
/// <param name="edge"></param>
/// <param name="l"></param>
/// <param name="eiCurr"></param>
/// <param name="eiNext"></param>
public void CreateEdgeEndForNext(Edge edge, IList<EdgeEnd> l, EdgeIntersection eiCurr, EdgeIntersection eiNext)
{
int iNext = eiCurr.SegmentIndex + 1;
// if there is no next edge there is nothing to do
if (iNext >= edge.NumPoints && eiNext == null)
return;
Coordinate pNext = edge.GetCoordinate(iNext);
// if the next intersection is in the same segment as the current, use it as the endpoint
if (eiNext != null && eiNext.SegmentIndex == eiCurr.SegmentIndex)
pNext = eiNext.Coordinate;
EdgeEnd e = new EdgeEnd(edge, eiCurr.Coordinate, pNext, new Label(edge.Label));
l.Add(e);
}
/// <summary>
/// Creates new edges for all the edges that the intersections in this
/// list split the parent edge into.
/// Adds the edges to the input list (this is so a single list
/// can be used to accumulate all split edges for a Geometry).
/// </summary>
/// <param name="edgeList"></param>
public void AddSplitEdges(IList <Edge> edgeList)
{
// ensure that the list has entries for the first and last point of the edge
AddEndpoints();
IEnumerator <EdgeIntersection> it = GetEnumerator();
it.MoveNext();
// there should always be at least two entries in the list
EdgeIntersection eiPrev = it.Current;
while (it.MoveNext())
{
EdgeIntersection ei = it.Current;
Edge newEdge = CreateSplitEdge(eiPrev, ei);
edgeList.Add(newEdge);
eiPrev = ei;
}
}
/// <summary>
/// Create a EdgeStub for the edge before the intersection eiCurr.
/// The previous intersection is provided
/// in case it is the endpoint for the stub edge.
/// Otherwise, the previous point from the parent edge will be the endpoint.
/// eiCurr will always be an EdgeIntersection, but eiPrev may be null.
/// </summary>
/// <param name="edge"></param>
/// <param name="l"></param>
/// <param name="eiCurr"></param>
/// <param name="eiPrev"></param>
public void CreateEdgeEndForPrev(Edge edge, IList<EdgeEnd> l, EdgeIntersection eiCurr, EdgeIntersection eiPrev)
{
int iPrev = eiCurr.SegmentIndex;
if (eiCurr.Distance == 0.0)
{
// if at the start of the edge there is no previous edge
if (iPrev == 0)
return;
iPrev--;
}
Coordinate pPrev = edge.GetCoordinate(iPrev);
// if prev intersection is past the previous vertex, use it instead
if (eiPrev != null && eiPrev.SegmentIndex >= iPrev)
pPrev = eiPrev.Coordinate;
Label label = new Label(edge.Label);
// since edgeStub is oriented opposite to it's parent edge, have to flip sides for edge label
label.Flip();
EdgeEnd e = new EdgeEnd(edge, eiCurr.Coordinate, pPrev, label);
l.Add(e);
}
/// <summary>
/// Create a new "split edge" with the section of points between
/// (and including) the two intersections.
/// The label for the new edge is the same as the label for the parent edge.
/// </summary>
/// <param name="ei0"></param>
/// <param name="ei1"></param>
public Edge CreateSplitEdge(EdgeIntersection ei0, EdgeIntersection ei1)
{
int npts = ei1.SegmentIndex - ei0.SegmentIndex + 2;
Coordinate lastSegStartPt = edge.Points[ei1.SegmentIndex];
// if the last intersection point is not equal to the its segment start pt,
// add it to the points list as well.
// (This check is needed because the distance metric is not totally reliable!)
// The check for point equality is 2D only - Z values are ignored
bool useIntPt1 = ei1.Distance > 0.0 || ! ei1.Coordinate.Equals2D(lastSegStartPt);
if (! useIntPt1)
npts--;
Coordinate[] pts = new Coordinate[npts];
int ipt = 0;
pts[ipt++] = new Coordinate(ei0.Coordinate);
for (int i = ei0.SegmentIndex + 1; i <= ei1.SegmentIndex; i++)
pts[ipt++] = edge.Points[i];
if (useIntPt1)
pts[ipt] = ei1.Coordinate;
return new Edge(pts, new Label(edge.Label));
}
/// <summary>
///
/// </summary>
/// <param name="obj"></param>
/// <returns></returns>
public int CompareTo(object obj)
{
EdgeIntersection other = (EdgeIntersection)obj;
return(Compare(other.SegmentIndex, other.Distance));
}
