static Point[] GetIntersections(Segment S, ConicBezier F)
{
// Segment To y = kx + b format...
double k = (S.to.y - S.from.y) / (S.to.x - S.from.x);
if (eq(1.0 / k, eps)) // slope is infinity, or near infinity.
{
return(Mapping <Point, double>(
F.Interpolate,
Filter <double>(
x => (0.0 <= x && x < 1.0 && S.CoveringPoint(F.Interpolate(x))),
SolveSquare(F.from.x - S.from.x, 2.0 * (F.control.x - F.from.x), F.from.x + F.to.x - 2.0 * F.control.x))));
}
else
{
double b = S.to.y - k * S.to.x;
Point N = F.from + F.to - 2.0 * F.control;
Point M = 2.0 * (F.control - F.from);
Point Q = F.from;
double A = k * N.x - N.y;
double B = k * M.x - M.y;
double C = k * Q.x - Q.y + b;
return(Mapping <Point, double>(
F.Interpolate,
Filter <double>(
x => (0.0 <= x && x <= 1.0 && S.CoveringPoint(F.Interpolate(x))),
SolveSquare(A, B, C))));
}
}
// ====================================================================
// Tool Functions for Shapes
// ====================================================================
/// <summary>
/// Intersections includes *from* points, exclude *to* points.
/// </summary>
static Point[] GetIntersections(ConicBezier F, Segment S) => GetIntersections(S, F);
