/// <summary>
/// Converts a Label to a Line label (that is, one with no side Locations).
/// </summary>
/// <param name="label">Label to convert.</param>
/// <returns>Label as Line label.</returns>
public static Label ToLineLabel(Label label)
{
Label lineLabel = new Label(Locations.Null);
for (int i = 0; i < 2; i++)
lineLabel.SetLocation(i, label.GetLocation(i));
return lineLabel;
}
/// <summary>
/// Converts a Label to a Line label (that is, one with no side Locations).
/// </summary>
/// <param name="label">Label to convert.</param>
/// <returns>Label as Line label.</returns>
public static Label ToLineLabel(Label label)
{
Label lineLabel = new Label(Locations.Null);
for (int i = 0; i < 2; i++)
{
lineLabel.SetLocation(i, label.GetLocation(i));
}
return(lineLabel);
}
/// <summary>
///
/// </summary>
/// <param name="argIndex"></param>
/// <param name="coord"></param>
/// <param name="onLocation"></param>
private void InsertPoint(int argIndex, ICoordinate coord, Locations onLocation)
{
Node n = nodes.AddNode(coord);
Label lbl = n.Label;
if (lbl == null)
{
n.Label = new Label(argIndex, onLocation);
}
else
{
lbl.SetLocation(argIndex, onLocation);
}
}
/// <summary>
/// Merge the RHS label from a DirectedEdge into the label for this EdgeRing.
/// The DirectedEdge label may be null. This is acceptable - it results
/// from a node which is NOT an intersection node between the Geometries
/// (e.g. the end node of a LinearRing). In this case the DirectedEdge label
/// does not contribute any information to the overall labelling, and is simply skipped.
/// </summary>
/// <param name="deLabel"></param>
/// <param name="geomIndex"></param>
protected void MergeLabel(Label deLabel, int geomIndex)
{
Locations loc = deLabel.GetLocation(geomIndex, Positions.Right);
// no information to be had from this label
if (loc == Locations.Null)
{
return;
}
// if there is no current RHS value, set it
if (label.GetLocation(geomIndex) == Locations.Null)
{
label.SetLocation(geomIndex, loc);
return;
}
}
/// <summary>
/// Adds points using the mod-2 rule of SFS. This is used to add the boundary
/// points of dim-1 geometries (Curves/MultiCurves). According to the SFS,
/// an endpoint of a Curve is on the boundary
/// if it is in the boundaries of an odd number of Geometries.
/// </summary>
/// <param name="argIndex"></param>
/// <param name="coord"></param>
private void InsertBoundaryPoint(int argIndex, ICoordinate coord)
{
Node n = nodes.AddNode(coord);
Label lbl = n.Label;
// the new point to insert is on a boundary
int boundaryCount = 1;
// determine the current location for the point (if any)
Locations loc = Locations.Null;
if (lbl != null)
{
loc = lbl.GetLocation(argIndex, Positions.On);
}
if (loc == Locations.Boundary)
{
boundaryCount++;
}
// determine the boundary status of the point according to the Boundary Determination Rule
Locations newLoc = DetermineBoundary(boundaryCount);
lbl.SetLocation(argIndex, newLoc);
}
/// <summary>
/// Compute the labelling for all dirEdges in this star, as well
/// as the overall labelling.
/// </summary>
/// <param name="geom"></param>
public override void ComputeLabelling(GeometryGraph[] geom)
{
base.ComputeLabelling(geom);
// determine the overall labelling for this DirectedEdgeStar
// (i.e. for the node it is based at)
label = new Label(Locations.Null);
IEnumerator it = GetEnumerator();
while (it.MoveNext())
{
EdgeEnd ee = (EdgeEnd)it.Current;
Edge e = ee.Edge;
Label eLabel = e.Label;
for (int i = 0; i < 2; i++)
{
Locations eLoc = eLabel.GetLocation(i);
if (eLoc == Locations.Interior || eLoc == Locations.Boundary)
{
label.SetLocation(i, Locations.Interior);
}
}
}
}
/// <summary>
/// Compute the labelling for all dirEdges in this star, as well
/// as the overall labelling.
/// </summary>
/// <param name="geom"></param>
public override void ComputeLabelling(GeometryGraph[] geom)
{
base.ComputeLabelling(geom);
// determine the overall labelling for this DirectedEdgeStar
// (i.e. for the node it is based at)
label = new Label(Locations.Null);
IEnumerator it = GetEnumerator();
while(it.MoveNext())
{
EdgeEnd ee = (EdgeEnd)it.Current;
Edge e = ee.Edge;
Label eLabel = e.Label;
for (int i = 0; i < 2; i++)
{
Locations eLoc = eLabel.GetLocation(i);
if (eLoc == Locations.Interior || eLoc == Locations.Boundary)
label.SetLocation(i, Locations.Interior);
}
}
}
/// <summary>
///
/// </summary>
/// <param name="geomIndex"></param>
public void PropagateSideLabels(int geomIndex)
{
// 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
Locations startLoc = Locations.Null;
// initialize loc to location of last Curve side (if any)
for (IEnumerator it = GetEnumerator(); it.MoveNext();)
{
EdgeEnd e = (EdgeEnd)it.Current;
Label label = e.Label;
if (label.IsArea(geomIndex) && label.GetLocation(geomIndex, Positions.Left) != Locations.Null)
{
startLoc = label.GetLocation(geomIndex, Positions.Left);
}
}
// no labelled sides found, so no labels to propagate
if (startLoc == Locations.Null)
{
return;
}
Locations currLoc = startLoc;
for (IEnumerator it = GetEnumerator(); it.MoveNext();)
{
EdgeEnd e = (EdgeEnd)it.Current;
Label label = e.Label;
// set null On values to be in current location
if (label.GetLocation(geomIndex, Positions.On) == Locations.Null)
{
label.SetLocation(geomIndex, Positions.On, currLoc);
}
// set side labels (if any)
if (label.IsArea(geomIndex))
{
Locations leftLoc = label.GetLocation(geomIndex, Positions.Left);
Locations rightLoc = label.GetLocation(geomIndex, Positions.Right);
// if there is a right location, that is the next location to propagate
if (rightLoc != Locations.Null)
{
if (rightLoc != currLoc)
{
throw new TopologyException("side location conflict", e.Coordinate);
}
if (leftLoc == Locations.Null)
{
Assert.ShouldNeverReachHere("found single null side (at " + e.Coordinate + ")");
}
currLoc = leftLoc;
}
else
{
/* RHS is null - LHS must be null too.
* This must be an edge from the other point, which has no location
* labelling for this point. This edge must lie wholly inside or outside
* the other point (which is determined by the current location).
* Assign both sides to be the current location.
*/
Assert.IsTrue(label.GetLocation(geomIndex, Positions.Left) == Locations.Null, "found single null side");
label.SetLocation(geomIndex, Positions.Right, currLoc);
label.SetLocation(geomIndex, Positions.Left, currLoc);
}
}
}
}