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);
}
/// <summary>
/// Returns true if the child is entirely contained within the parent, inclusive the edges.
/// Assumes that there is no intersection between the two subpaths, touchings allowed.
/// </summary>
private static bool Contains(Subpath parent, Subpath child)
{
if (!PointInPolygonTest.Contains(parent.PolygonApproximation, child.PolygonApproximation.InsidePoint))
{
return(false);
}
return(child.PolygonApproximation.Points.Any(x => PointInPolygonTest.Contains(parent.PolygonApproximation, x)));
}