public static float PointToSegment(Point p1, Segment s)
{
// this is from the web - don't ask exactly how it works!
PointF p=new PointF(p1.X, p1.Y);
Vector v = new Vector(s.P1, s.P0);
Vector w = new Vector(p, s.P0);
double c1 = w * v;
if ( c1 <= 0 )
// this handles the case when the point is
// nearer the first end point than a point on the line
return Distance(p, s.P0);
double c2 = v * v;
if ( c2 <= c1 )
// this handles the case when the point is
// nearer the second end point than a point on the line
return Distance(p, s.P1);
double b = c1 / c2;
PointF Pb= s.P0 + (v * b);
return Distance(p, Pb);
}
/// Calculate how far a given point is from the spiro curve
private bool PointNearSegment(Point pt)
{
if (points == null)
Init();
// go around the shape and construct a segment from consecutive
// points and see how far the point is from the segment
PointF pt1 = new PointF(points[0].X, points[0].Y);
for (int n = 1; n < points.Length; n++)
{
PointF pt2 = new PointF(points[n].X, points[n].Y);
Segment s = new Segment(pt1, pt2);
if (LineUtil.PointToSegment(pt, s) < 5)
return true;
pt1 = pt2;
}
return false;
}