public Point OtherPoint(Segment seg)
{
if (seg.HasPoint(A) && seg.HasPoint(B))
{
return(C);
}
if (seg.HasPoint(A) && seg.HasPoint(C))
{
return(B);
}
if (seg.HasPoint(B) && seg.HasPoint(C))
{
return(A);
}
if (seg.PointLiesOn(A) && seg.PointLiesOn(B))
{
return(C);
}
if (seg.PointLiesOn(A) && seg.PointLiesOn(C))
{
return(B);
}
if (seg.PointLiesOn(B) && seg.PointLiesOn(C))
{
return(A);
}
return(null);
}
public bool LooseCrosses(Segment that)
{
Point p = this.FindIntersection(that);
if (p == null)
{
return(false);
}
if (this.HasPoint(p) || that.HasPoint(p))
{
return(false);
}
return(LooseBetween(p, this.Point1, this.Point2) && LooseBetween(p, that.Point1, that.Point2));
}
public Point OtherPoint(Segment cs)
{
if (!cs.HasPoint(Point1)) return Point1;
if (!cs.HasPoint(Point2)) return Point2;
if (!cs.HasPoint(Point3)) return Point3;
return null;
}
//
// Is this a direct radius segment where one endpoint originates at the origin and extends outward?
// Return the exact radius.
private Segment IsRadius(Segment segment, List<Point> figPoints)
{
// The segment must originate from the circle center.
if (!segment.HasPoint(this.center)) return null;
// The segment must be at least as long as a radius.
if (!Utilities.CompareValues(segment.Length, this.radius)) return null;
Point nonCenterPt = segment.OtherPoint(this.center);
// Check for a direct radius.
if (this.PointLiesOn(nonCenterPt)) return segment;
//
// Check for an extended segment.
//
// radius
// center _____ circPt
//
// Find the exact coordinates of the 'circ' points.
//
Point inter1 = null;
Point inter2 = null;
this.FindIntersection(segment, out inter1, out inter2);
Point figPoint = Utilities.GetStructurally<Point>(figPoints, inter1);
if (figPoint == null) figPoint = Utilities.GetStructurally<Point>(figPoints, inter2);
return new Segment(center, figPoint);
}
public bool LooseCrosses(Segment that)
{
Point p = this.FindIntersection(that);
if (p == null) return false;
if (this.HasPoint(p) || that.HasPoint(p)) return false;
return LooseBetween(p, this.Point1, this.Point2) && LooseBetween(p, that.Point1, that.Point2);
}
public Point OtherPoint(Segment seg)
{
if (seg.HasPoint(A) && seg.HasPoint(B)) return C;
if (seg.HasPoint(A) && seg.HasPoint(C)) return B;
if (seg.HasPoint(B) && seg.HasPoint(C)) return A;
if (seg.PointLiesOn(A) && seg.PointLiesOn(B)) return C;
if (seg.PointLiesOn(A) && seg.PointLiesOn(C)) return B;
if (seg.PointLiesOn(B) && seg.PointLiesOn(C)) return A;
return null;
}
// top
// o
// offStands oooooooe
// e
//offEndpoint eeeeeee
// o
// bottom
// Returns: <offEndpoint, offStands>
public KeyValuePair <Point, Point> CreatesSimplePIShape(Intersection thatInter)
{
KeyValuePair <Point, Point> nullPair = new KeyValuePair <Point, Point>(null, null);
// A valid transversal is required for this shape
if (!this.CreatesAValidTransversalWith(thatInter))
{
return(nullPair);
}
// Restrict to desired combination
if (this.StandsOnEndpoint() && thatInter.StandsOnEndpoint())
{
return(nullPair);
}
//
// Determine which is the stands and which is the endpoint
//
Intersection endpointInter = null;
Intersection standsInter = null;
if (this.StandsOnEndpoint() && thatInter.StandsOn())
{
endpointInter = this;
standsInter = thatInter;
}
else if (thatInter.StandsOnEndpoint() && this.StandsOn())
{
endpointInter = this;
standsInter = thatInter;
}
else
{
return(nullPair);
}
//
// Avoid Some shapes
//
Segment transversal = this.AcquireTransversal(thatInter);
Segment transversalStands = standsInter.GetCollinearSegment(transversal);
Point top = null;
Point bottom = null;
if (Segment.Between(standsInter.intersect, transversalStands.Point1, endpointInter.intersect))
{
top = transversalStands.Point1;
bottom = transversalStands.Point2;
}
else
{
top = transversalStands.Point2;
bottom = transversalStands.Point1;
}
// Avoid: ____ Although this shouldn't happen since both intersections do not stand on endpoints
// ____|
//
// Also avoid Simple F-Shape
//
if (transversal.HasPoint(top) || transversal.HasPoint(bottom))
{
return(nullPair);
}
// Determine S shape
Point offStands = standsInter.CreatesTShape();
Segment parallelEndpoint = endpointInter.OtherSegment(transversal);
Point offEndpoint = parallelEndpoint.OtherPoint(endpointInter.intersect);
Segment crossingTester = new Segment(offStands, offEndpoint);
Point intersection = transversal.FindIntersection(crossingTester);
// S-shape // PI-Shape
return(transversal.PointLiesOnAndBetweenEndpoints(intersection) ? nullPair : new KeyValuePair <Point, Point>(offEndpoint, offStands));
}
//
// Creates an F-Shape
// top
// _____ offEnd <--- Stands on Endpt
// |
// |_____ offStands <--- Stands on
// |
// |
// bottom
// Order of non-collinear points is order of intersections: <this, that>
public KeyValuePair <Point, Point> CreatesFShape(Intersection thatInter)
{
KeyValuePair <Point, Point> nullPair = new KeyValuePair <Point, Point>(null, null);
// A valid transversal is required for this shape
if (!this.CreatesAValidTransversalWith(thatInter))
{
return(nullPair);
}
// Avoid both standing on an endpoint
if (this.StandsOnEndpoint() && thatInter.StandsOnEndpoint())
{
return(nullPair);
}
Intersection endpt = null;
Intersection standsOn = null;
if (this.StandsOnEndpoint() && thatInter.StandsOn())
{
endpt = this;
standsOn = thatInter;
}
else if (thatInter.StandsOnEndpoint() && this.StandsOn())
{
endpt = thatInter;
standsOn = this;
}
else
{
return(nullPair);
}
Segment transversal = this.AcquireTransversal(thatInter);
Segment transversalStands = standsOn.GetCollinearSegment(transversal);
//
// Determine Top and bottom to avoid PI shape
//
Point top = null;
Point bottom = null;
if (Segment.Between(standsOn.intersect, transversalStands.Point1, endpt.intersect))
{
bottom = transversalStands.Point1;
top = transversalStands.Point2;
}
else
{
bottom = transversalStands.Point2;
top = transversalStands.Point1;
}
// Avoid: ____ Although this shouldn't happen since both intersections do not stand on endpoints
// ____|
if (transversal.HasPoint(top) && transversal.HasPoint(bottom))
{
return(nullPair);
}
// Also avoid Simple PI-Shape
//
if (!transversal.HasPoint(top) && !transversal.HasPoint(bottom))
{
return(nullPair);
}
// Find the two points that make the points of the F
Segment parallelEndPt = endpt.OtherSegment(transversal);
Segment parallelStands = standsOn.OtherSegment(transversal);
Point offEnd = transversal.PointLiesOn(parallelEndPt.Point1) ? parallelEndPt.Point2 : parallelEndPt.Point1;
Point offStands = transversal.PointLiesOn(parallelStands.Point1) ? parallelStands.Point2 : parallelStands.Point1;
// Check this is not a crazy F
// _____
// |
// ____|
// |
// |
Point intersection = transversal.FindIntersection(new Segment(offEnd, offStands));
if (transversal.PointLiesOnAndBetweenEndpoints(intersection))
{
return(nullPair);
}
// Return in the order of 'off' points: <this, that>
return(this.Equals(endpt) ? new KeyValuePair <Point, Point>(offEnd, offStands) : new KeyValuePair <Point, Point>(offStands, offEnd));
}
