/// <summary>
/// NOTE: Rotation will need to be added to this function
/// </summary>
/// <param name="c">Ellipse centre</param>
/// <param name="rx">Ellipse X radius</param>
/// <param name="ry">Ellipse Y radius</param>
/// <param name="a1">Line P1</param>
/// <param name="a2">Line P2</param>
/// <returns></returns>
public static Intersection IntersectEllipseLine(CADPoint c, double rx, double ry, CADPoint a1, CADPoint a2)
{
Intersection result;
var origin = new CADVector(a1.X, a1.Y);
var dir = a2 - a1;
var center = new CADVector(c.X, c.Y);
var diff = origin - center;
var mDir = new CADVector(dir.X / (rx * rx), dir.Y / (ry * ry));
var mDiff = new CADVector(diff.X / (rx * rx), diff.Y / (ry * ry));
var a = CADVector.Dot(dir, mDir);
var b = CADVector.Dot(dir, mDiff);
var cc = CADVector.Dot(diff, mDiff) - 1.0;
var d = b * b - a * cc;
if (d < 0)
{
result = new Intersection(Intersection.IntStatus.Outside);
}
else if (d > 0)
{
var root = Math.Sqrt(d);
var t_a = (-b - root) / a;
var t_b = (-b + root) / a;
if ((t_a < 0 || 1 < t_a) && (t_b < 0 || 1 < t_b))
{
if ((t_a < 0 && t_b < 0) || (t_a > 1 && t_b > 1))
{
result = new Intersection(Intersection.IntStatus.Outside);
}
else
{
result = new Intersection(Intersection.IntStatus.Inside);
}
}
else
{
result = new Intersection(Intersection.IntStatus.Intersection);
if (0 <= t_a && t_a <= 1)
{
result.appendPoint(a1.lerp(a2, t_a));
}
if (0 <= t_b && t_b <= 1)
{
result.appendPoint(a1.lerp(a2, t_b));
}
}
}
else
{
var t = -b / a;
if (0 <= t && t <= 1)
{
result = new Intersection(Intersection.IntStatus.Intersection);
result.appendPoint(a1.lerp(a2, t));
}
else
{
result = new Intersection(Intersection.IntStatus.Outside);
}
}
return(result);
}
/// <summary>
///
/// </summary>
/// <param name="c">Ellipse centre</param>
/// <param name="rx">Ellipse X radius</param>
/// <param name="ry">Ellipse Y radius</param>
/// <param name="r1">first corner of the rectangle</param>
/// <param name="r2">opposite corner of the rectangle</param>
/// <returns></returns>
public static Intersection IntersectEllipseRectangle(CADPoint c, double rx, double ry, CADPoint r1, CADPoint r2)
{
var min = r1.Min(r2);
var max = r1.Max(r2);
var topRight = new CADPoint(max.X, min.Y);
var bottomLeft = new CADPoint(min.X, max.Y);
var inter1 = IntersectEllipseLine(c, rx, ry, min, topRight);
var inter2 = IntersectEllipseLine(c, rx, ry, topRight, max);
var inter3 = IntersectEllipseLine(c, rx, ry, max, bottomLeft);
var inter4 = IntersectEllipseLine(c, rx, ry, bottomLeft, min);
var result = new Intersection(Intersection.IntStatus.No_Intersection);
result.appendPoints(inter1.Points);
result.appendPoints(inter2.Points);
result.appendPoints(inter3.Points);
result.appendPoints(inter4.Points);
if (result.Points.Count > 0)
{
result.Status = Intersection.IntStatus.Intersection;
}
return(result);
}
public CADPoint Max(CADPoint point2)
{
return(new CADPoint(Math.Max(X, point2.X), Math.Max(Y, point2.Y)));
}
public void appendPoint(CADPoint point)
{
Points.Add(point);
}
public static double Distance(CADPoint a, CADPoint b)
{
CADVector vector = b - a;
return(vector.Length);
}
