public override void Recalculate()
{
// first assume we exist
Exists = true;
// if any of our dependencies don't exist, return
UpdateExistence();
if (!Exists)
{
return;
}
var figure1 = Dependencies.ElementAt(0);
var figure2 = Dependencies.ElementAt(1);
if (Algorithm == null)
{
Exists = false;
return;
}
Point p = Algorithm(figure1, figure2);
if (!p.Exists() || figure1.HitTest(p) == null || figure2.HitTest(p) == null)
{
Exists = false;
return;
}
Exists = true;
Coordinates = p;
}
public static bool IsPointInPolygon(this IList <Point> polygon, Point start)
{
var outsidePoint = new Point(polygon.Max(p => p.X) + 100, 0);
var segment = new PointPair(start, outsidePoint);
int n = polygon.Count;
int intersectionsCount = 0;
for (int i = 0; i < n; i++)
{
PointPair side = new PointPair(polygon[i], polygon[i.RotateNext(n)]);
Point intersectionPoint = GetIntersectionOfLines(segment, side);
if (!intersectionPoint.Exists())
{
continue;
}
if (IsPointInSegmentBoundingRect(side, intersectionPoint) &&
IsPointInSegmentBoundingRect(segment, intersectionPoint) &&
intersectionPoint != side.P2)
{
if (intersectionPoint == side.P1 &&
Math.VectorProduct(start, side.P1, polygon[i.RotatePrevious(n)]).Sign()
== Math.VectorProduct(start, side.P1, side.P2).Sign())
{
continue;
}
intersectionsCount++;
}
}
return(intersectionsCount % 2 == 1);
}
public static Func <IFigure, IFigure, Point> PickCloserIntersectionPoint(
Func <IFigure, IFigure, Point> algorithm1,
Func <IFigure, IFigure, Point> algorithm2,
IFigure figure1,
IFigure figure2,
Point hintPoint)
{
Point p1 = algorithm1(figure1, figure2);
Point p2 = algorithm2(figure1, figure2);
if (!p1.Exists())
{
if (p2.Exists())
{
return(algorithm2);
}
else
{
return(algorithm1);
}
}
else
{
if (!p2.Exists())
{
return(algorithm1);
}
else
{
var d1 = p1.Distance(hintPoint);
var d2 = p2.Distance(hintPoint);
if (d1 < d2)
{
return(algorithm1);
}
else
{
return(algorithm2);
}
}
}
}
public static Point GetIntersectionOfSegments(PointPair segment1, PointPair segment2)
{
Point result = GetIntersectionOfLines(segment1, segment2);
if (!result.Exists())
{
return(result);
}
if (IsPointInSegmentInnerBoundingRect(segment1, result) &&
IsPointInSegmentInnerBoundingRect(segment2, result))
{
return(result);
}
return(Math.InfinitePoint);
}
public static List <Point> GetIntersections(IList <Point> polygon, PointPair segment)
{
List <Point> result = new List <Point>();
int n = polygon.Count;
for (int i = 0; i < n; i++)
{
PointPair side = new PointPair(polygon[i], polygon[i.RotateNext(n)]);
Point intersection = GetIntersectionOfSegments(side, segment);
if (intersection.Exists() && intersection != polygon[i.RotateNext(n)])
{
result.Add(intersection);
}
}
return(result);
}
public override void Recalculate()
{
if (!Dependencies.Exists())
{
Exists = false;
return;
}
var figure1 = LinearFigure;
Point p = figure1.GetPointFromParameter(Parameter);
bool HitTestFailed = (UseHitTestingForExistence) ? LinearFigure.HitTest(p) == null : false;
if (!p.Exists() || HitTestFailed)
{
Exists = false;
return;
}
Exists = true;
Coordinates = p;
}