public static double DistanceFromSegment(this Point pnt, Point segStart, Point segEnd)
{
Contract.Ensures(Contract.Result <double>() >= 0);
return((pnt - pnt.ProjectOnSegment(segStart, segEnd)).Length);
}
public static Tuple <Point, double, int> ProjectionOnCurve(this Point point, IEnumerable <Point> curve)
{
Contract.Requires(curve != null);
Contract.Requires(curve.Count() >= 2);
Contract.Ensures(Contract.Result <Tuple <Point, double, int> >().Item2 >= 0); // distance is greater than zero
Contract.Ensures(Contract.Result <Tuple <Point, double, int> >().Item3 >= 0); // index is greater than zero
Contract.Ensures(Contract.Result <Tuple <Point, double, int> >().Item3 < curve.Count() - 1); // segment index is less than num of segments
// The projected point is closer to "point" than any other point on the curve.
Contract.Ensures(Contract.ForAll(curve, curvePoint =>
(curvePoint - point).Length >= Contract.Result <Tuple <Point, double, int> >().Item2));
var count = curve.Count();
var projectedPoints =
from indexedSegment in curve.SeqPairs().ZipIndex()
let index = indexedSegment.Index
let segment = indexedSegment.Value
let segStart = segment.Item1
let segEnd = segment.Item2
let projectedPoint = point.ProjectOnSegment(segStart, segEnd)
let distance = (point - projectedPoint).Length
select Tuple.Create(projectedPoint, distance, index);
return(projectedPoints.Minimizer(pair => pair.Item2)); // Item2 is the distance
}
