public double DistToPoint(Point2D p, out Point2D footPos)
{
double minDist = this.points.Min(x => x.DistTo(p));
Point2D minPoint = this.points.First(x => x.DistTo(p) == minDist);
if (minPoint == this.points.First())
{
LineSeg seg1 = new LineSeg(this.points[0], this.points[1]);
LineSegPointRelation relation1 = new LineSegPointRelation(seg1, p);
if (relation1.Inner)
{
footPos = relation1.Foot;
return(relation1.Dist);
}
else
{
footPos = minPoint;
return(minDist);
}
}
else if (minPoint == this.points.Last())
{
int n = this.points.Count;
LineSeg seg1 = new LineSeg(this.points[n - 2], this.points[n - 1]);
LineSegPointRelation relation1 = new LineSegPointRelation(seg1, p);
if (relation1.Inner)
{
footPos = relation1.Foot;
return(relation1.Dist);
}
else
{
footPos = minPoint;
return(minDist);
}
}
else
{
int index = this.points.IndexOf(minPoint);
LineSeg seg1 = new LineSeg(this.points[index - 1], this.points[index]);
LineSeg seg2 = new LineSeg(this.points[index + 1], this.points[index]);
LineSegPointRelation relation1 = new LineSegPointRelation(seg1, p);
LineSegPointRelation relation2 = new LineSegPointRelation(seg2, p);
if (relation1.Inner)
{
footPos = relation1.Foot;
return(relation1.Dist);
}
else if (relation2.Inner)
{
footPos = relation2.Foot;
return(relation2.Dist);
}
else
{
footPos = minPoint;
return(minDist);
}
}
}
public LineSegIntersect(LineSeg l1, LineSeg l2)
{
A = l1.p[0];
B = l1.p[1];
C = l2.p[0];
D = l2.p[1];
}
public LineSegPointRelation(LineSeg line, Point2D point)
{
A = line.p[0];
B = line.p[1];
C = point;
if (line.IsPointOn(point))
{
D = C;
lambda = (A.x - C.x) / (C.x - B.x);
if (double.IsNaN(lambda))
{
lambda = (A.y - C.y) / (C.y - B.y);
}
}
else
{
lambda = (-A.x * A.x + A.x * B.x + A.x * C.x - B.x * C.x - A.y * A.y + A.y * B.y + A.y * C.y - B.y * C.y) / (A.x * B.x - B.x * B.x - A.x * C.x + B.x * C.x + A.y * B.y - B.y * B.y - A.y * C.y + B.y * C.y); // from Mathematica
D = line.GetDivPoint(lambda);
}
}