public bool ArePointsOnTheSameSide(PointD[] points)
{
FreeVector segmentVector = new FreeVector(_beg, _end);
PointD beg = _beg;
var r = points.Select(p => (segmentVector.GetDirection(new FreeVector(beg, p))));
return(r.All(x => x == Direction.Anticlockwise) ||
r.All(x => x == Direction.Clockwise));
}
protected override double[] _GetNormalVector(int x, int y)
{
double[] N = null;
PointD a = new PointD(0, 0);
PointD b = new PointD(0, _canvasHeight);
PointD c = new PointD(_canvasWidth, _canvasHeight);
PointD d = new PointD(_canvasWidth, 0);
FreeVector cs = new FreeVector(c, a) / 2;
PointD s = c + cs;
FreeVector bs = new FreeVector(b, d) / 2;
// determine the place
Direction bsDirection = bs.GetDirection(new FreeVector(new PointD(x - b.X, y - b.Y)));
Direction csDirection = cs.GetDirection(new FreeVector(new PointD(x - c.X, y - c.Y)));
if (bsDirection == Direction.Anticlockwise && csDirection == Direction.Clockwise) // 0
{
N = new double[] { 0, s.Y, cs.Length };
}
else if (bsDirection == Direction.Clockwise && csDirection == Direction.Clockwise) // 1
{
N = new double[] { -s.X, 0, cs.Length };
}
else if (bsDirection == Direction.Clockwise && csDirection == Direction.Anticlockwise) // 2
{
N = new double[] { 0, -s.Y, cs.Length };
}
else if (bsDirection == Direction.Anticlockwise && csDirection == Direction.Anticlockwise) // 3
{
N = new double[] { s.X, 0, cs.Length };
}
return(N);
}
