/// <summary>
/// Determines the squared distance from this ring to the given point <paramref name="p"/>.
/// </summary>
/// <param name="p">The point to determine the squared distance to.</param>
/// <returns>The squared distance from this ring to the given point <paramref name="p"/>.</returns>
/// <remarks>
/// The squared distance will be 0 when the ring is a fill and the point lies within the boundary, when the ring is a hole and the point lies outside of the boundary, or when the point lies on the boundary.
/// </remarks>
public double DistanceSquared(Point2 p)
{
Contract.Ensures(
Contract.Result <double>() >= 0.0 ||
Double.IsNaN(Contract.Result <double>()) ||
Double.IsPositiveInfinity(Contract.Result <double>()));
var lastIndex = _pointList.Count - 1;
if (lastIndex > 1)
{
if (Intersects(p, false))
{
return(0);
}
var d = Segment2.DistanceSquared(_pointList[lastIndex], _pointList[0], p);
for (int i = 0, nextIndex = 1; i < lastIndex; i = nextIndex++)
{
d = Math.Min(d, Segment2.DistanceSquared(_pointList[i], _pointList[nextIndex], p));
}
return(d);
}
return(0 == lastIndex
? _pointList[0].DistanceSquared(p)
: 1 == lastIndex
? Segment2.DistanceSquared(_pointList[0], _pointList[1], p)
: Double.NaN
);
}
/// <summary>
/// Calculates the squared distance between this line string and the point, <paramref name="p"/>.
/// </summary>
/// <param name="p">The point to calculate squared distance to.</param>
/// <returns>The squared distance.</returns>
public double DistanceSquared(Point2 p)
{
Contract.Ensures(Contract.Result <double>() >= 0.0 || Contract.Result <double>().Equals(Double.NaN));
var lastIndex = Count - 1;
if (lastIndex < 1)
{
return(0 == lastIndex ? this[0].DistanceSquared(p) : Double.NaN);
}
var minDistance = Segment2.DistanceSquared(this[0], this[1], p);
for (int i = 1, nextIndex = 2; i < lastIndex; i = nextIndex++)
{
var localDistance = Segment2.DistanceSquared(this[i], this[nextIndex], p);
if (localDistance < minDistance)
{
minDistance = localDistance;
}
}
return(minDistance);
}
