public static double DistToPoint(this PointString poly, Vector p, int divs) // newly 20130523 近似法
{
var points = poly.Points;
double delta = (double)(points.Count - 1) / divs;
var pts = Enumerable.Range(0, divs + 1).Select(i => poly.Lerp(i * delta)).ToList();
return(pts.Min(pt => pt.Dist(p)));
}
public static PointString GetSubPoly(this PointString poly, double start, double end)
{
var points = poly.Points;
start = (start < 0) ? 0 : start;
end = (end > points.Count - 1) ? (points.Count - 1) : end;
var pts = new List <Vector>();
double a = Math.Ceiling(start);
double b = Math.Floor(end);
for (int i = (int)a; i <= (int)b; i++)
{
pts.Add(points[i]);
}
if (start < a)
{
pts.Insert(0, poly.Lerp(start));
}
if (end > b)
{
pts.Add(poly.Lerp(end));
}
return(new PointString(pts));
}