/// <summary>
/// Create a polygon with vertex id's and next chain. Can contain holes.
/// </summary>
/// <param name="vertexCoordinates">the coordinates</param>
/// <param name="vertexIds">the vertex ids</param>
/// <param name="nextIndices">the next index in vertexIds. Must be same length as vertexIds</param>
/// <param name="fusionVertices">Vertices that are used in more than one subpolygon. Can be null.</param>
/// <returns>a polygon</returns>
public static Polygon FromVertexList(Vertex[] vertexCoordinates, IEnumerable <int> vertexIds, IEnumerable <int> nextIndices, IEnumerable <int> polygonIds, IReadOnlyList <int> fusionVertices)
{
var vertexIdCollection = vertexIds as IReadOnlyCollection <int> ?? vertexIds.ToArray();
var polygonIdCollection = polygonIds as IList <int> ?? polygonIds.ToArray();
var vertexToChain = Enumerable.Repeat(-1, vertexCoordinates.Length).ToArray();
var vertexChain = new VertexChain[vertexIdCollection.Count];
var polygonStartIndex = new List <int>();
var i = 0;
foreach (var(vertexId, nextId) in vertexIdCollection.Zip(nextIndices, Tuple.Create))
{
vertexChain[i].VertexId = vertexId;
vertexChain[i].SameVertexChain = vertexToChain[vertexId];
vertexChain[i].SubPolygonId = polygonIdCollection[i];
SetNext(vertexChain, i, nextId);
if (polygonIdCollection[i] >= polygonStartIndex.Count)
{
polygonStartIndex.Add(i);
}
vertexToChain[vertexId] = i;
i++;
}
var polygon = new Polygon(vertexCoordinates, vertexChain, vertexToChain, polygonStartIndex);
polygon.FusionVerticesIntoChain(fusionVertices);
return(polygon);
}
/// <summary>
/// create a polygon from multiple polygon lines
/// </summary>
/// <param name="vertexCoordinates">the vertex coordinates</param>
/// <param name="lines">The polygon lines. Each vertex Id must be unique inside a polygon line.</param>
/// <param name="fusionVertices">vertices that are used in more than one subpolygon</param>
/// <returns>a polygon</returns>
public static Polygon FromPolygonLines(Vertex[] vertexCoordinates, IReadOnlyCollection <int>[] lines, IReadOnlyList <int> fusionVertices)
{
var vertexChain = new VertexChain[lines.Sum(x => x.Count)];
var id = 0;
var first = id;
var vertexToChain = Enumerable.Repeat(-1, vertexCoordinates.Length).ToArray();
var subPolygones = new List <int>();
foreach (var line in lines)
{
var polygonId = subPolygones.Count;
subPolygones.Add(id);
foreach (var vertexId in line)
{
vertexChain[id].VertexId = vertexId;
vertexChain[id].SubPolygonId = polygonId;
vertexChain[id].SameVertexChain = vertexToChain[vertexId];
vertexToChain[vertexId] = id;
SetNext(vertexChain, id, id == vertexChain.Length - 1 ? first : id + 1);
id++;
}
SetNext(vertexChain, id - 1, first);
first = id;
}
var polygon = new Polygon(vertexCoordinates, vertexChain, vertexToChain, subPolygones);
polygon.FusionVerticesIntoChain(fusionVertices);
return(polygon);
}