public static double Distance2(Vector2 point, IClosedPolyline line)
{
var prevVector = line.Vertices.Last() - point;
var prevNorm2 = prevVector.Norm2;
var answer = prevNorm2;
foreach (var vertex in line.Vertices)
{
var vector = vertex - point;
var norm2 = vector.Norm2;
var displacement = vector - prevVector;
if ((prevVector * displacement) * (vector * displacement) > 0)
{
answer = Math.Min(answer, norm2);
}
else
{
answer = Math.Min(answer, BasicMath.Sqr(prevVector.Cross(vector)) / displacement.Norm2);
}
prevVector = vector;
prevNorm2 = norm2;
}
return(answer);
}
public static int WindingNumber(this IClosedPolyline @this, Vector2 point)
{
var answer = 0;
var prevVector = @this.Vertices.Last() - point;
foreach (var vertex in @this.Vertices)
{
var vector = vertex - point;
if (vector.Y * prevVector.Y < 0 && // edge crosses X axis
vector.Y * prevVector.Cross(vector) > 0) // edge crosses positive half of X axis
{
if (vector.Y > 0)
{
answer++; // counterclockwise crossing
}
else
{
answer--; // clockwise crossing
}
}
prevVector = vector;
}
return(answer);
}
public VerticalPrism(IClosedPolyline @base, Interval zRange) : base(@base, zRange, isClosed: true)
{
if (!_isCounterclockwise)
{
throw new ArgumentException("@base has to be counterclockwise", "@base");
}
_basePolygon = new Polygon(@base);
}
public static void FindClosestPoint(this IClosedPolyline @this, Vector2 point, out Vector2 closestPoint, out double distance2)
{
var prevVector = @this.Vertices.Last() - point;
var prevNorm2 = prevVector.Norm2;
closestPoint = @this.Vertices.Last();
distance2 = prevNorm2;
foreach (var vertex in @this.Vertices)
{
var vector = vertex - point;
var norm2 = vector.Norm2;
var displacement = vector - prevVector;
var vectorDotDisplacement = vector * displacement;
if ((prevVector * displacement) * vectorDotDisplacement > 0)
{
if (norm2 < distance2)
{
closestPoint = vertex;
distance2 = norm2;
}
}
else
{
var displacementNorm2 = displacement.Norm2;
var perpendicularLength2 = BasicMath.Sqr(prevVector.Cross(vector)) / displacementNorm2;
if (perpendicularLength2 < distance2)
{
closestPoint = vertex - vectorDotDisplacement * displacement / displacementNorm2;
distance2 = perpendicularLength2;
}
}
prevVector = vector;
prevNorm2 = norm2;
}
}
public static IClosedPolyline TranslateBy(this IClosedPolyline @this, Vector2 translation)
{
return(new ClosedPolyline(@this.Vertices.Select(v => v + translation)));
}
public static double DistanceTo(this Vector2 @this, IClosedPolyline line)
{
return(Math.Sqrt(Distance2(@this, line)));
}
public static IClosedPolyline FromBoxCoords(this IClosedPolyline @this, Box2 box)
{
return(new ClosedPolyline(@this.Vertices.Select(v => v.FromBoxCoords(box))));
}
public void AddContour(IClosedPolyline contour)
{
_contours.Add(contour);
}
public static Segment2 GetEdge(this IClosedPolyline @this, int index)
{
var vertices = @this.Vertices;
return(new Segment2(vertices.ElementAtCyclic(index), vertices.ElementAtCyclic(index + 1)));
}
public static Vector2 GetVertex(this IClosedPolyline @this, int index)
{
return(@this.Vertices.ElementAtCyclic(index));
}
public static Vector2 Normal(this IClosedPolyline @this, int index)
{
return(Displacement(@this, index).Rotate270().Normalized);
}
public static IClosedPolyline ApplyInv(this Rotation2 @this, IClosedPolyline line)
{
return(new ClosedPolyline(line.Vertices.Select(v => @this.ApplyInv(v))));
}
private static ClipperContour MinusConvertToFixedPoint(IClosedPolyline p, Box2 range)
{
return((from vertex in p.Vertices select MinusConvertToFixedPoint(vertex, range)).ToList());
}
public static Vector2 Displacement(this IClosedPolyline @this, int index)
{
var vertices = @this.Vertices;
return(vertices.ElementAtCyclic(index + 1) - vertices.ElementAtCyclic(index));
}
public static IClosedPolyline AsReverse(this IClosedPolyline @this)
{
return(new ClosedPolyline(@this.Vertices.AsReverse()));
}
public Polygon(IClosedPolyline contour)
{
_contours = contour.AsSingleton();
_boundingBox = Box2.Hull(contour.Vertices);
}
public ClosedPolyline(IClosedPolyline line)
{
_vertices = line.Vertices;
}
