public void TestDistanceOfPointAndLine()
{
Vector2 lpo = new Vector2()
{
X = 0, Y = 10
}; //直线上的点点
Vector2 lv = new Vector2()
{
X = 1, Y = 1
}; //直线方向向量（非0）
Vector2 outerPoint = new Vector2()
{
X = 10, Y = 10
}; //直线上或者直线外的一点
Vector2 result = new Vector2()
{
X = 1, Y = 1
}; //过outerPoint作l的垂线，result为垂足
float distance = OutputCoordinate.DistanceOfPointAndLine(lpo, lv, outerPoint, ref result); //点到直线距离
Assert.AreEqual(distance, 5 * Math.Sqrt(2), delta);
Assert.IsFalse(result.X == 1);
Assert.IsFalse(result.Y == 1);
float dotMulti = Vector2.Dot(outerPoint - result, lv); //垂线
Assert.AreEqual(dotMulti, 0f, delta);
Vector2 result2 = new Vector2();
float distance2 = OutputCoordinate.DistanceOfPointAndLine(lpo, lv, result, ref result2); //垂足在l上
Assert.AreEqual(distance2, 0f, delta);
}
/// <summary>
/// 直线可能与另一条直线相交，交点有0,、1个，也可能与一个圆相交，交点有0、1、2个
/// </summary>
/// <param name="another">another可能是一个Circle或者Line</param>
/// <returns>交点是一个Point2的数组(List)</returns>
List <Point2> IPointSet.Intersection(IPointSet another)
{
List <Point2> pcl = new List <Point2>(); //point cross list
if (another is Line)
{
Line l2 = another as Line; //转换
Vector2 v1 = this.GetVector();
Vector2 v2 = l2.GetVector();
Point2 p1 = this.GetCenterPoint();
Point2 p2 = l2.GetCenterPoint();
FMatrix <double> matrix = new FMatrix <double>(2, 3, 0);
//if(Vector2.Zero) //理论上来说两个直线方向向量都不会为0
Vector3 v31 = new Vector3()
{
X = v1.X, Y = v1.Y, Z = 0
};
Vector3 v32 = new Vector3()
{
X = v2.X, Y = v2.Y, Z = 0
};
Vector3 multiVector = Vector3.Cross(v31, v32); //向量积、叉积
if (multiVector.Length() > 1e-7) //几乎平行
{
matrix[0][0] = v1.X;
matrix[0][1] = -v2.X;
matrix[0][2] = p2.X - p1.X;
matrix[1][0] = v1.Y;
matrix[1][1] = -v2.Y;
matrix[1][2] = p2.Y - p1.Y;
FMatrix <double> simpleMatrix = FMatrix <double> .RowSimplestFormOf(matrix);
Point2 onePoint = new Point2()
{
X = p1.X + (float)simpleMatrix[0][2] * v1.X, Y = p1.Y + (float)simpleMatrix[0][2] * v1.Y
};
onePoint.rely.Add(this);
onePoint.rely.Add((Geometry)another);
onePoint.markOfTwoIntersectPointOnCircle = true;
pcl.Add(onePoint); //存在一个交点
}
}
else if (another is Circle)
{
Circle c2 = another as Circle;
float radius = c2.GetRadius();
Vector2 lv = this.GetVector();
Vector2 result = new Vector2();
float distance = OutputCoordinate.DistanceOfPointAndLine(this.GetCenterPoint().ToVector2(), this.GetVector(), c2.center.ToVector2(), ref result);
float halfChord = (float)Math.Sqrt(Math.Pow(radius, 2.0) - Math.Pow(distance, 2.0)); //弦长的一半
if (radius >= distance) //直线过圆
{
Vector2 lve = Vector2.Normalize(lv);
Vector2 vd1 = lve * halfChord;
Vector2 vd2 = Vector2.Negate(lve) * halfChord;
Point2 p1 = new Point2()
{
X = result.X + vd1.X, Y = result.Y + vd1.Y
};
Point2 p2 = new Point2()
{
X = result.X + vd2.X, Y = result.Y + vd2.Y
};
bool counterclockwise = true; //逆时针
if ((p1.X - c2.center.X) * (p2.Y - c2.center.Y) - (p1.Y - c2.center.Y) * (p2.X - c2.center.X) < 0) //顺时针
{
counterclockwise = false;
}
p1.rely.Add(this);
p1.rely.Add((Geometry)another);
p1.markOfTwoIntersectPointOnCircle = counterclockwise;
p2.rely.Add(this);
p2.rely.Add((Geometry)another);
p2.markOfTwoIntersectPointOnCircle = !counterclockwise;
pcl.Add(p1);
pcl.Add(p2);
}
}
return(pcl);
}