private static void Subdivide(List <SKPoint> path, int desiredPointCount)
{
var desiredLength = path.Count + desiredPointCount;
var step = SKGeometry.Perimeter(path) / desiredPointCount;
var i = 0;
var cursor = 0.0f;
var insertAt = step / 2f;
while (path.Count < desiredLength)
{
var a = path[i];
var b = path[(i + 1) % path.Count];
var segment = SKGeometry.Distance(a, b);
if (insertAt <= cursor + segment)
{
path.Insert(i + 1, segment != 0 ? SKGeometry.PointAlong(a, b, (insertAt - cursor) / segment) : a);
insertAt += step;
continue;
}
cursor += segment;
i++;
}
}
private static void Rotate(List <SKPoint> from, List <SKPoint> to)
{
var bestOffset = 0;
var min = float.PositiveInfinity;
var len = from.Count;
for (var offset = 0; offset < len; offset++)
{
var sumOfSquares = 0.0f;
for (var i = 0; i < len; i++)
{
var d = SKGeometry.Distance(from[(offset + i) % len], to[i]);
sumOfSquares += d * d;
}
if (sumOfSquares < min)
{
min = sumOfSquares;
bestOffset = offset;
}
}
if (bestOffset != 0)
{
Rotate(from, bestOffset);
}
}
private static void Bisect(List <SKPoint> ring, float maxSegmentLength)
{
// skip if we have asked that the path not be bisected
if (maxSegmentLength <= 0)
{
return;
}
for (var i = 0; i < ring.Count; i++)
{
var a = ring[i];
var b = i == ring.Count - 1 ? ring[0] : ring[i + 1];
// could splice the whole set for a segment instead, but a bit messy
while (SKGeometry.Distance(a, b) > maxSegmentLength)
{
b = SKGeometry.PointAlong(a, b, 0.5f);
ring.Insert(i + 1, b);
}
}
}
private static List <SKPoint> NormalizePath(SKPath parsed, float maxSegmentLength)
{
var skipBisect = false;
var points = CreateLinearPathPoints(parsed);
if (points == null)
{
points = CreateCurvedPathPoints(parsed, maxSegmentLength);
skipBisect = true;
}
// TODO:
//// no duplicate closing point for now
//if (points.Count > 1 && SKGeometry.Distance(points[0], points[points.Count - 1]) < 1e-9f)
//{
// points.pop();
//}
// 3+ points to make a polygon
if (points.Count < 3)
{
return(null);
}
// make all rings clockwise
if (SKGeometry.Area(points) > 0)
{
points.Reverse();
}
if (!skipBisect && maxSegmentLength > 0)
{
Bisect(points, maxSegmentLength);
}
return(points);
}
