/// <summary>
/// Converts all <see cref="VoronoiRegions"/> to a planar <see cref="Subdivision"/>.
/// </summary>
/// <returns>
/// A <see cref="SubdivisionMap"/> containing a new <see cref="Subdivision"/> whose bounded
/// <see cref="Subdivision.Faces"/> correspond to the <see cref="VoronoiRegions"/> of the
/// <see cref="VoronoiResults"/>.</returns>
/// <remarks><para>
/// The returned <see cref="SubdivisionMap"/> also provides a mapping between the zero-based
/// indices of all <see cref="GeneratorSites"/> and <see cref="VoronoiRegions"/> and the
/// corresponding <see cref="Subdivision.Faces"/>. This mapping will become invalid as soon
/// as the created <see cref="Subdivision"/> is changed.
/// </para><para>
/// <b>ToVoronoiSubdivision</b> creates all <see cref="VoronoiRegions"/> if they have not
/// yet been calculated. Call <see cref="ClearVoronoiRegions"/> if you no longer require
/// this property after <b>ToVoronoiSubdivision</b> has returned.</para></remarks>
public SubdivisionMap ToVoronoiSubdivision()
{
var division = Subdivision.FromPolygons(VoronoiRegions);
int regionCount = VoronoiRegions.Length;
Debug.Assert(GeneratorSites.Length == regionCount);
Debug.Assert(division.Faces.Count == regionCount + 1);
var faceToSite = new int[regionCount];
var siteToFace = new SubdivisionFace[regionCount];
// determine equivalence of faces and VoronoiRegions indices
// (which are in turn equivalent to GeneratorSites indices)
for (int i = 0; i < VoronoiRegions.Length; i++)
{
PointD[] polygon = VoronoiRegions[i];
SubdivisionFace face = division.FindFace(polygon);
// bounded faces start at creation index one
faceToSite[face._key - 1] = i;
siteToFace[i] = face;
}
return(new SubdivisionMap(division, this, faceToSite, siteToFace));
}
/// <summary>
/// Initializes a new instance of the <see cref="SubdivisionEdge"/> class with the specified
/// unique key, origin, incident face, twin, next and previous half-edge.</summary>
/// <param name="key">
/// The unique key of the <see cref="SubdivisionEdge"/> within its containing <see
/// cref="Subdivision"/>.</param>
/// <param name="origin">
/// The coordinates where the <see cref="SubdivisionEdge"/> begins.</param>
/// <param name="twin">
/// The <see cref="SubdivisionEdge"/> that is the twin of the current instance.</param>
/// <param name="face">
/// The <see cref="SubdivisionFace"/> that is bounded by the <see cref="SubdivisionEdge"/>.
/// </param>
/// <param name="next">
/// The next <see cref="SubdivisionEdge"/> that bounds the same <paramref name="face"/>.
/// </param>
/// <param name="previous">
/// The previous <see cref="SubdivisionEdge"/> that bounds the same <paramref name="face"/>.
/// </param>
/// <remarks>
/// This constructor is intended for unit testing.</remarks>
internal SubdivisionEdge(int key, PointD origin, SubdivisionEdge twin,
SubdivisionFace face, SubdivisionEdge next, SubdivisionEdge previous)
{
_key = key;
_origin = origin;
_twin = twin;
_face = face;
_next = next;
_previous = previous;
}
/// <summary>
/// Sets the <see cref="Face"/> property of this <see cref="SubdivisionEdge"/> and all other
/// half-edges in the same cycle to the specified value.</summary>
/// <param name="face">
/// The new value for the <see cref="Face"/> property of each <see cref="SubdivisionEdge"/>.
/// </param>
internal void SetAllFaces(SubdivisionFace face)
{
Debug.Assert(face != null);
SubdivisionEdge cursor = this;
do
{
cursor._face = face;
cursor = cursor._next;
} while (cursor != this);
}
/// <summary>
/// Initializes a new instance of the <see cref="SubdivisionElement"/> structure with the
/// specified <see cref="SubdivisionFace"/>.</summary>
/// <param name="face">
/// The <see cref="SubdivisionFace"/> stored in the <see cref="SubdivisionElement"/>.
/// </param>
/// <remarks>
/// <see cref="ElementType"/> is set to <see cref="SubdivisionElementType.Face"/>.</remarks>
public SubdivisionElement(SubdivisionFace face)
{
ElementType = SubdivisionElementType.Face;
_value = face;
_vertex = PointD.Empty;
}
/// <summary>
/// Converts the specified <see cref="SubdivisionFace"/> into the associated <see
/// cref="GeneratorSites"/> index.</summary>
/// <param name="face">
/// The <see cref="SubdivisionFace"/> to convert.</param>
/// <returns>
/// The zero-based <see cref="GeneratorSites"/> index associated with <paramref
/// name="face"/>.</returns>
/// <exception cref="IndexOutOfRangeException">
/// <paramref name="face"/> contains a <see cref="SubdivisionFace.Key"/> that is less
/// than one or greater than the number of <see cref="GeneratorSites"/>.</exception>
/// <exception cref="NullReferenceException">
/// <paramref name="face"/> is a null reference.</exception>
public int FromFace(SubdivisionFace face)
{
return(_faceToSite[face._key - 1]);
}
