public static Point GetInsidePoint(IReadOnlyList <Point> points, Box boundingBox)
{
var y = (boundingBox.MinY + boundingBox.MaxY) / 2;
var xIntersections = new List <double>();
var point1 = points.Last();
foreach (var point2 in points)
{
if ((y > point1.Y) != (y > point2.Y))
{
xIntersections.Add((y - point2.Y) * (point1.X - point2.X) / (point1.Y - point2.Y) + point2.X);
}
point1 = point2;
}
xIntersections.Sort();
Debugger.BreakWhen(xIntersections.Count == 0 || xIntersections.Count % 2 != 0);
var x = (boundingBox.MinX + boundingBox.MaxX) / 2;
var maxDelta = double.NegativeInfinity;
for (var i = 0; i < xIntersections.Count - 1; i += 2)
{
var delta = Math.Abs(xIntersections[i] - xIntersections[i + 1]);
if (delta > maxDelta)
{
x = (xIntersections[i] + xIntersections[i + 1]) / 2;
maxDelta = delta;
}
}
var point = new Point(x, y);
#if DEBUG
Debugger.BreakWhen(!PointInPolygonTest.Contains(points, point));
#endif
return(point);
}
public static IEnumerable <Subpath> Unify(IEnumerable <Subpath> subpaths)
{
var collection = new SubpathCollection();
foreach (var subpath in subpaths)
{
if (subpath.AreSegmentsClosed)
{
if (HasFillArea(subpath))
{
yield return(subpath);
}
}
else
{
collection.Add(subpath);
}
}
var subpath1 = collection.Dequeue();
while (subpath1 != null)
{
var concatenations = collection.GetAll(subpath1.EndPoint).ToArray();
Debugger.BreakWhen(concatenations.Length == 0);
if (concatenations.Length > 0)
{
var subpath2 = ChooseConcatenation(subpath1, concatenations);
collection.Remove(subpath2);
subpath1 = new Subpath(subpath1.StartPoint, subpath1.Segments.Concat(subpath2.Segments), false);
if (!subpath1.AreSegmentsClosed)
{
continue;
}
}
if (HasFillArea(subpath1))
{
yield return(subpath1);
}
subpath1 = collection.Dequeue();
}
}
private static Point SplitByNextIntersection(Point startPoint, SegmentBase segment, out SegmentBase segment1, out SegmentBase segment2,
CurveEquation equation,
Func <double, Point, SegmentBase> factory1,
Func <double, SegmentBase> factory2)
{
var intersection = segment.Intersections.Select(x => new { Point = x, T = equation.GetT(x) }).MinBy(x => x.T);
var t = Math.Min(Math.Max(intersection.T, 0), 1);
var point = equation.GetPoint(t);
segment1 = point == startPoint ? null : factory1(t, intersection.Point);
if (point == segment.EndPoint)
{
segment2 = null;
Debugger.BreakWhen(segment.Intersections.Count > 1);
}
else
{
segment2 = factory2(t);
segment2.Intersections.AddRange(segment.Intersections.Where(x => x != intersection.Point));
}
return(intersection.Point);
}