public static Intersection QuadraticBezierLineSegmentIntersection0(
double p1X, double p1Y,
double p2X, double p2Y,
double p3X, double p3Y,
double a1X, double a1Y,
double a2X, double a2Y,
double epsilon = Epsilon)
{
var min = MinPointTests.MinPoint(a1X, a1Y, a2X, a2Y);
var max = MaxPointTests.MaxPoint(a1X, a1Y, a2X, a2Y);
var result = new Intersection(IntersectionStates.NoIntersection);
var a = new Vector2D(p2X, p2Y) * (-2);
var c2 = new Vector2D(p1X, p1Y) + (a + new Vector2D(p3X, p3Y));
a = new Vector2D(p1X, p1Y) * (-2);
var b = new Vector2D(p2X, p2Y) * 2;
var c1 = a + b;
var c0 = new Point2D(p1X, p1Y);
var n = new Point2D(a1Y - a2Y, a2X - a1X);
var cl = (a1X * a2Y) - (a2X * a1Y);
var roots = QuadraticRootsTests.QuadraticRoots(
DotProduct2Vector2DTests.DotProduct2D(n.X, n.Y, c2.I, c2.J),
DotProduct2Vector2DTests.DotProduct2D(n.X, n.Y, c1.I, c1.J),
DotProduct2Vector2DTests.DotProduct2D(n.X, n.Y, c0.X + cl, c0.Y + cl),
epsilon);
for (var i = 0; i < roots.Count; i++)
{
var t = roots[i];
if (0 <= t && t <= 1)
{
var p4 = InterpolateLinear2DTests.LinearInterpolate2D(t, p1X, p1Y, p2X, p2Y);
var p5 = InterpolateLinear2DTests.LinearInterpolate2D(t, p2X, p2Y, p3X, p3Y);
var p6 = InterpolateLinear2DTests.LinearInterpolate2D(t, p4.X, p4.Y, p5.X, p5.Y);
if (a1X == a2X)
{
if (min.Y <= p6.Y && p6.Y <= max.Y)
{
result.State = IntersectionStates.Intersection;
result.AppendPoint(p6);
}
}
else if (a1Y == a2Y)
{
if (min.X <= p6.X && p6.X <= max.X)
{
result.State = IntersectionStates.Intersection;
result.AppendPoint(p6);
}
}
else if (GreaterThanOrEqualTests.GreaterThanOrEqual(p6.X, p6.Y, min.X, min.Y) && LessThanOrEqualTests.LessThanOrEqual(p6.X, p6.Y, max.X, max.Y))
{
result.State = IntersectionStates.Intersection;
result.AppendPoint(p6);
}
}
}
return(result);
}
/// <summary>
/// Calculate the geometry of points offset at a specified distance. aka Double Line.
/// </summary>
/// <param name="pointA">First reference point.</param>
/// <param name="pointB">First inclusive point.</param>
/// <param name="pointC">Second inclusive point.</param>
/// <param name="pointD">Second reference point.</param>
/// <param name="offsetDistance">Offset Distance</param>
/// <returns></returns>
/// <acknowledgment>
/// Suppose you have 4 points; A, B C, and D. With Lines AB, BC, and CD.<BR/>
///<BR/>
/// B1 BC1 C1<BR/>
/// |\¯B¯¯¯¯¯BC¯¯¯C¯¯¯/|<BR/>
/// | \--------------/ |<BR/>
/// | |\____________/| |<BR/>
/// | | |B2 BC2 C2| | |<BR/>
/// AB| | | | | |CD<BR/>
/// AB1| | |AB2 CD2| | |CD1<BR/>
/// | | | | | |<BR/>
/// | | | | | |<BR/>
/// A1 A A2 D2 D D1<BR/>
///
/// </acknowledgment>
public static Point2D[] CenteredOffsetLinePoints(Point2D pointA, Point2D pointB, Point2D pointC, Point2D pointD, double offsetDistance)
{
// To get the vectors of the angles at each corner B and C, Normalize the Unit Delta Vectors along AB, BC, and CD.
var UnitVectorAB = pointB - pointA;
UnitVectorAB = new Vector2D(Normalize2DVectorTests.Normalize(UnitVectorAB.I, UnitVectorAB.J));
var UnitVectorBC = pointC - pointB;
UnitVectorBC = new Vector2D(Normalize2DVectorTests.Normalize(UnitVectorBC.I, UnitVectorBC.J));
var UnitVectorCD = pointD - pointC;
UnitVectorCD = new Vector2D(Normalize2DVectorTests.Normalize(UnitVectorCD.I, UnitVectorCD.J));
// Find the Perpendicular of the outside vectors
var PerpendicularAB = new Vector2D(PerpendicularClockwiseVectorTests.PerpendicularClockwise(UnitVectorAB.I, UnitVectorAB.J));
var PerpendicularCD = new Vector2D(PerpendicularClockwiseVectorTests.PerpendicularClockwise(UnitVectorCD.I, UnitVectorCD.J));
// Normalized Vectors pointing out from B and C.
var OutUnitVectorB = UnitVectorAB - UnitVectorBC;
OutUnitVectorB = new Vector2D(Normalize2DVectorTests.Normalize(OutUnitVectorB.I, OutUnitVectorB.J));
var OutUnitVectorC = UnitVectorCD - UnitVectorBC;
OutUnitVectorC = new Vector2D(Normalize2DVectorTests.Normalize(OutUnitVectorC.I, OutUnitVectorC.J));
// The distance out from B is the radius / Cos(theta) where theta is the angle
// from the perpendicular of BC of the UnitVector. The cosine can also be
// calculated by doing the dot product of Unit(Perpendicular(AB)) and
// UnitVector.
var BPointScale = DotProduct2Vector2DTests.DotProduct2D(PerpendicularAB.I, PerpendicularAB.J, OutUnitVectorB.I, OutUnitVectorB.J) * offsetDistance;
var CPointScale = DotProduct2Vector2DTests.DotProduct2D(PerpendicularCD.I, PerpendicularCD.J, OutUnitVectorC.I, OutUnitVectorC.J) * offsetDistance;
OutUnitVectorB *= CPointScale;
OutUnitVectorC *= BPointScale;
// Corners of the parallelogram to draw
var Out = new Point2D[] {
pointC + OutUnitVectorC,
pointB + OutUnitVectorB,
pointB - OutUnitVectorB,
pointC - OutUnitVectorC,
pointC + OutUnitVectorC
};
return(Out);
}
public static Intersection UnrotatedEllipseLineSegmentIntersection0(
double centerX, double centerY,
double rx, double ry,
double a1X, double a1Y,
double a2X, double a2Y,
double epsilon = Epsilon)
{
_ = epsilon;
var origin = new Vector2D(a1X, a1Y);
var dir = new Vector2D(a1X, a1Y, a2X, a2Y);
var diff = origin - new Vector2D(centerX, centerY);
var mDir = new Vector2D(dir.I / (rx * rx), dir.J / (ry * ry));
var mDiff = new Vector2D(diff.I / (rx * rx), diff.J / (ry * ry));
var a = DotProduct2Vector2DTests.DotProduct2D(dir.I, dir.J, mDir.I, mDir.J);
var b = DotProduct2Vector2DTests.DotProduct2D(dir.I, dir.J, mDiff.I, mDiff.J);
var c = DotProduct2Vector2DTests.DotProduct2D(diff.I, diff.J, mDiff.I, mDiff.J) - 1d;
var d = (b * b) - (a * c);
Intersection result;
if (d < 0)
{
result = new Intersection(IntersectionStates.Outside);
}
else if (d > 0)
{
var root = 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))
{
result = (t_a < 0 && t_b < 0) || (t_a > 1 && t_b > 1) ? new Intersection(IntersectionStates.Outside) : new Intersection(IntersectionStates.Inside);
}
else
{
result = new Intersection(IntersectionStates.Intersection);
if (0 <= t_a && t_a <= 1)
{
result.AppendPoint(InterpolateLinear2DTests.LinearInterpolate2D(t_a, a1X, a1Y, a2X, a2Y));
}
if (0 <= t_b && t_b <= 1)
{
result.AppendPoint(InterpolateLinear2DTests.LinearInterpolate2D(t_b, a1X, a1Y, a2X, a2Y));
}
}
}
else
{
var t = -b / a; if (0 <= t && t <= 1)
{
result = new Intersection(IntersectionStates.Intersection);
result.AppendPoint(InterpolateLinear2DTests.LinearInterpolate2D(t, a1X, a1Y, a2X, a2Y));
}
else
{
result = new Intersection(IntersectionStates.Outside);
}
}
return(result);
}
public static Intersection UnrotatedEllipticalArcLineSegmentIntersection0(
double cx, double cy,
double rx, double ry,
double startAngle, double sweepAngle,
double x0, double y0,
double x1, double y1, double epsilon = Epsilon)
{
_ = epsilon;
// Initialize the resulting intersection structure.
var result = new Intersection(IntersectionStates.NoIntersection);
// Translate the line to put the ellipse centered at the origin.
var origin = new Vector2D(x0, y0);
var dir = new Vector2D(x0, y0, x1, y1);
var diff = origin - new Vector2D(cx, cy);
var mDir = new Vector2D(dir.I / (rx * rx), dir.J / (ry * ry));
var mDiff = new Vector2D(diff.I / (rx * rx), diff.J / (ry * ry));
// Calculate the quadratic parameters.
var a = DotProduct2Vector2DTests.DotProduct2D(dir.I, dir.J, mDir.I, mDir.J);
var b = DotProduct2Vector2DTests.DotProduct2D(dir.I, dir.J, mDiff.I, mDiff.J);
var c = DotProduct2Vector2DTests.DotProduct2D(diff.I, diff.J, mDiff.I, mDiff.J) - 1d;
// Calculate the discriminant of the quadratic. The 4 is omitted.
var discriminant = (b * b) - (a * c);
// Check whether line segment is outside of the ellipse.
if (discriminant < 0d)
{
return(new Intersection(IntersectionStates.Outside));
}
// Find the start and end angles.
var sa = EllipticalPolarAngleTests.EllipticalPolarAngle(startAngle, rx, ry);
var ea = EllipticalPolarAngleTests.EllipticalPolarAngle(startAngle + sweepAngle, rx, ry);
// Get the ellipse rotation transform.
var cosT = Cos(0d);
var sinT = Sin(0d);
// Ellipse equation for an ellipse at origin for the chord end points.
var u1 = rx * Cos(sa);
var v1 = -(ry * Sin(sa));
var u2 = rx * Cos(ea);
var v2 = -(ry * Sin(ea));
// Find the points of the chord.
var sX = cx + ((u1 * cosT) + (v1 * sinT));
var sY = cy + ((u1 * sinT) - (v1 * cosT));
var eX = cx + ((u2 * cosT) + (v2 * sinT));
var eY = cy + ((u2 * sinT) - (v2 * cosT));
if (discriminant > 0d)
{
// Two real possible solutions.
var root = Sqrt(discriminant);
var t1 = (-b - root) / a;
var t2 = (-b + root) / a;
if ((t1 < 0d || 1d < t1) && (t2 < 0d || 1d < t2))
{
result = (t1 < 0d && t2 < 0d) || (t1 > 1d && t2 > 1d) ? new Intersection(IntersectionStates.Outside) : new Intersection(IntersectionStates.Inside);
}
else
{
var p = InterpolateLinear2DTests.LinearInterpolate2D(t1, x0, y0, x1, y1);
// Find the determinant of the chord.
var determinant = ((sX - p.X) * (eY - p.Y)) - ((eX - p.X) * (sY - p.Y));
// Check whether the point is on the side of the chord as the center.
if (0d <= t1 && t1 <= 1d && (Sign(determinant) != Sign(sweepAngle)))
{
result.AppendPoint(p);
}
p = InterpolateLinear2DTests.LinearInterpolate2D(t2, x0, y0, x1, y1);
// Find the determinant of the chord.
determinant = ((sX - p.X) * (eY - p.Y)) - ((eX - p.X) * (sY - p.Y));
if (0d <= t2 && t2 <= 1 && (Sign(determinant) != Sign(sweepAngle)))
{
result.AppendPoint(p);
}
}
}
else // discriminant == 0.
{
// One real possible solution.
var t = -b / a;
if (t >= 0d && t <= 1d)
{
var p = InterpolateLinear2DTests.LinearInterpolate2D(t, x0, y0, x1, y1);
// Find the determinant of the matrix representing the chord.
var determinant = ((sX - p.X) * (eY - p.Y)) - ((eX - p.X) * (sY - p.Y));
// Add the point if it is on the sweep side of the chord.
if (Sign(determinant) != Sign(sweepAngle))
{
result.AppendPoint(InterpolateLinear2DTests.LinearInterpolate2D(t, x0, y0, x1, y1));
}
}
else
{
result = new Intersection(IntersectionStates.Outside);
}
}
if (result.Count > 0)
{
result.State |= IntersectionStates.Intersection;
}
return(result);
}
public static Intersection CubicBezierLineIntersection0(
double p1X, double p1Y,
double p2X, double p2Y,
double p3X, double p3Y,
double p4X, double p4Y,
double a1X, double a1Y,
double a2X, double a2Y,
double epsilon = Epsilon)
{
Vector2D a, b, c, d;
Vector2D c3, c2, c1, c0;
double cl;
Vector2D n;
var min = MinPointTests.MinPoint(a1X, a1Y, a2X, a2Y);
var max = MaxPointTests.MaxPoint(a1X, a1Y, a2X, a2Y);
var result = new Intersection(IntersectionStates.NoIntersection);
a = new Vector2D(p1X, p1Y) * (-1);
b = new Vector2D(p2X, p2Y) * 3;
c = new Vector2D(p3X, p3Y) * (-3);
d = a + (b + (c + new Vector2D(p4X, p4Y)));
c3 = new Vector2D(d.I, d.J);
a = new Vector2D(p1X, p1Y) * 3;
b = new Vector2D(p2X, p2Y) * (-6);
c = new Vector2D(p3X, p3Y) * 3;
d = a + (b + c);
c2 = new Vector2D(d.I, d.J);
a = new Vector2D(p1X, p1Y) * (-3);
b = new Vector2D(p2X, p2Y) * 3;
c = a + b;
c1 = new Vector2D(c.I, c.J);
c0 = new Vector2D(p1X, p1Y);
n = new Vector2D(a1Y - a2Y, a2X - a1X);
cl = (a1X * a2Y) - (a2X * a1Y);
var roots = CubicRootsTests.CubicRoots(
DotProduct2Vector2DTests.DotProduct2D(n.I, n.J, c3.I, c3.J),
DotProduct2Vector2DTests.DotProduct2D(n.I, n.J, c2.I, c2.J),
DotProduct2Vector2DTests.DotProduct2D(n.I, n.J, c1.I, c1.J),
DotProduct2Vector2DTests.DotProduct2D(n.I, n.J, c0.I + cl, c0.J + cl),
epsilon);
for (var i = 0; i < roots.Count; i++)
{
var t = roots[i];
if (0 <= t && t <= 1)
{
var p5 = InterpolateLinear2DTests.LinearInterpolate2D(t, p1X, p1Y, p2X, p2Y);
var p6 = InterpolateLinear2DTests.LinearInterpolate2D(t, p2X, p2Y, p3X, p3Y);
var p7 = InterpolateLinear2DTests.LinearInterpolate2D(t, p3X, p3Y, p4X, p4Y);
var p8 = InterpolateLinear2DTests.LinearInterpolate2D(t, p5.X, p5.Y, p6.X, p6.Y);
var p9 = InterpolateLinear2DTests.LinearInterpolate2D(t, p6.X, p6.Y, p7.X, p7.Y);
var p10 = InterpolateLinear2DTests.LinearInterpolate2D(t, p8.X, p8.Y, p9.X, p9.Y);
if (a1X == a2X)
{
result.State = IntersectionStates.Intersection;
result.AppendPoint(p10);
}
else if (a1Y == a2Y)
{
result.State = IntersectionStates.Intersection;
result.AppendPoint(p10);
}
else if (GreaterThanOrEqualTests.GreaterThanOrEqual(p10.X, p10.Y, min.X, min.Y) && LessThanOrEqualTests.LessThanOrEqual(p10.X, p10.Y, max.X, max.Y))
{
result.State = IntersectionStates.Intersection;
result.AppendPoint(p10);
}
}
}
return(result);
}
