/// <summary>
/// Compute the change in depth as an edge is crossed from R to L.
/// </summary>
/// <param name="label"></param>
private static int DepthDelta(Label label)
{
Locations lLoc = label.GetLocation(0, Positions.Left);
Locations rLoc = label.GetLocation(0, Positions.Right);
if (lLoc == Locations.Interior && rLoc == Locations.Exterior)
return 1;
else if (lLoc == Locations.Exterior && rLoc == Locations.Interior)
return -1;
return 0;
}
/// <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;
}
private int _depthDelta; // the change in area depth from the R to Curve side of this edge
/// <summary>
/// Updates an IM from the label for an edge.
/// Handles edges from both L and A geometries.
/// </summary>
/// <param name="im"></param>
/// <param name="label"></param>
public static void UpdateIM(Label label, IntersectionMatrix im)
{
im.SetAtLeastIfValid(label.GetLocation(0, Positions.On), label.GetLocation(1, Positions.On), Dimensions.Curve);
if (label.IsArea())
{
im.SetAtLeastIfValid(label.GetLocation(0, Positions.Left), label.GetLocation(1, Positions.Left), Dimensions.Surface);
im.SetAtLeastIfValid(label.GetLocation(0, Positions.Right), label.GetLocation(1, Positions.Right), Dimensions.Surface);
}
}
/// <summary>
///
/// </summary>
/// <param name="label"></param>
/// <param name="opCode"></param>
/// <returns></returns>
public static bool IsResultOfOp(Label label, SpatialFunctions opCode)
{
Locations loc0 = label.GetLocation(0);
Locations loc1 = label.GetLocation(1);
return IsResultOfOp(loc0, loc1, opCode);
}
/// <summary>
/// Update incomplete dirEdge labels from the labelling for the node.
/// </summary>
/// <param name="nodeLabel"></param>
public virtual void UpdateLabelling(Label nodeLabel)
{
for (IEnumerator it = GetEnumerator(); it.MoveNext(); )
{
DirectedEdge de = (DirectedEdge)it.Current;
Label label = de.Label;
label.SetAllLocationsIfNull(0, nodeLabel.GetLocation(0));
label.SetAllLocationsIfNull(1, nodeLabel.GetLocation(1));
}
}
/// <summary>
///
/// </summary>
/// <param name="lbl"></param>
public virtual void Add(Label lbl)
{
for (int i = 0; i < 2; i++)
{
for (int j = 1; j < 3; j++)
{
Locations loc = lbl.GetLocation(i, (Positions)j);
if (loc == Locations.Exterior || loc == Locations.Interior)
{
// initialize depth if it is null, otherwise add this location value
if (IsNull(i, (Positions)j))
depth[i,j] = DepthAtLocation(loc);
else depth[i,j] += DepthAtLocation(loc);
}
}
}
}
/// <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 virtual 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>
/// The location for a given eltIndex for a node will be one
/// of { Null, Interior, Boundary }.
/// A node may be on both the boundary and the interior of a point;
/// in this case, the rule is that the node is considered to be in the boundary.
/// The merged location is the maximum of the two input values.
/// </summary>
/// <param name="label2"></param>
/// <param name="eltIndex"></param>
public virtual Locations ComputeMergedLocation(Label label2, int eltIndex)
{
Locations loc = Locations.Null;
loc = Label.GetLocation(eltIndex);
if (!label2.IsNull(eltIndex))
{
Locations nLoc = label2.GetLocation(eltIndex);
if (loc != Locations.Boundary)
loc = nLoc;
}
return loc;
}