/// <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>
/// <returns>The SegmentIntersection found or added.</returns>
public void Add(Coordinate intPt, int segmentIndex)
{
SegmentNode eiNew = new SegmentNode(_edge, intPt, segmentIndex, _edge.GetSegmentOctant(segmentIndex));
SegmentNode ei = (SegmentNode)_nodeMap[eiNew];
if(ei != null)
{
// debugging sanity check
Assert.IsTrue(ei.Coordinate.Equals2D(intPt), "Found equal nodes with different coordinates");
return;
}
// node does not exist, so create it
_nodeMap.Add(eiNew, eiNew);
return;
}
/// <summary>
/// Consente di spostare l'enumeratore all'elemento successivo dell'insieme.
/// </summary>
/// <returns>
/// true se l'enumeratore è stato spostato correttamente in avanti in corrispondenza dell'elemento successivo; false se l'enumeratore ha raggiunto la fine dell'insieme.
/// </returns>
/// <exception cref="T:System.InvalidOperationException">L'insieme è stato modificato dopo la creazione dell'enumeratore. </exception>
public bool MoveNext()
{
if (_currNode == null)
{
_currNode = _nextNode;
_currSegIndex = _currNode.SegmentIndex;
ReadNextNode();
return true;
}
// check for trying to read too far
if (_nextNode == null)
return false;
if (_nextNode.SegmentIndex == _currNode.SegmentIndex)
{
_currNode = _nextNode;
_currSegIndex = _currNode.SegmentIndex;
ReadNextNode();
return true;
}
if (_nextNode.SegmentIndex > _currNode.SegmentIndex)
{
}
return false;
}
/// <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>
/// <returns></returns>
SegmentString CreateSplitEdge(SegmentNode ei0, SegmentNode ei1)
{
int npts = ei1.SegmentIndex - ei0.SegmentIndex + 2;
Coordinate lastSegStartPt = _edge.GetCoordinate(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.IsInterior || !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.GetCoordinate(i);
if (useIntPt1)
pts[ipt] = ei1.Coordinate;
return new SegmentString(pts, _edge.Data);
}
private void ReadNextNode()
{
if (_nodeIt.MoveNext())
_nextNode = (SegmentNode)_nodeIt.Current;
else _nextNode = null;
}
/// <summary>
///
/// </summary>
/// <param name="ei0"></param>
/// <param name="ei1"></param>
/// <param name="collapsedVertexIndex"></param>
/// <returns></returns>
private static bool FindCollapseIndex(SegmentNode ei0, SegmentNode ei1, int[] collapsedVertexIndex)
{
// only looking for equal nodes
if (!ei0.Coordinate.Equals2D(ei1.Coordinate))
return false;
int numVerticesBetween = ei1.SegmentIndex - ei0.SegmentIndex;
if (!ei1.IsInterior)
numVerticesBetween--;
// if there is a single vertex between the two equal nodes, this is a collapse
if (numVerticesBetween == 1)
{
collapsedVertexIndex[0] = ei0.SegmentIndex + 1;
return true;
}
return false;
}
