private static void drawContour(IList <PointF> controlPoints, Image <Bgr, byte> image)
{
const float CONTOUR_TENSION = 0;
/******************** contour and control points *********************/
var pointIndices = CardinalSpline.GetEqualyDistributedPoints(controlPoints, CONTOUR_TENSION, 500);
var points = CardinalSpline.InterpolateAt(controlPoints, CONTOUR_TENSION, pointIndices);
var normals = new List <LineSegment2DF>();
var normalIndices = CardinalSpline.GetEqualyDistributedPoints(controlPoints, CONTOUR_TENSION, 100);
foreach (var idx in normalIndices)
{
var pt = CardinalSpline.InterpolateAt(controlPoints, CONTOUR_TENSION, idx);
var normalDirection = CardinalSpline.NormalAt(controlPoints, CONTOUR_TENSION, idx);
var orientation = (int)Angle.ToDegrees(System.Math.Atan2(normalDirection.Y, normalDirection.X));
var normal = getLine(orientation, pt, 20);
normals.Add(normal);
}
/******************** contour and control points *********************/
image.Draw(points.ToArray(),
Bgr8.Blue,
3);
image.Draw(controlPoints.Select(x => new CircleF(x, 3)), Bgr8.Red, 3);
image.Draw(normals, Bgr8.Green, 3, false);
}