/// <summary>
/// 根据圆外一点计算圆弧切点
/// </summary>
/// <param name="outPoint"></param>
/// <param name="turnDirection"></param>
/// <returns></returns>
public Point3D GetTangentPointbyOutPoint(Point3D outPoint, TurnDirectionType turnDirection)
{
//List<Point3D> list = GetIntersectPointsWithLine(outPoint, this.Center);
//if (list == null || list.Count <= 0)
//{
// return null;
//}
double outPointToCenterDistance = Center.DisTo(outPoint);
if (Math.Abs(outPointToCenterDistance - Radius) < OverrallVraTool.DoublePrecision) //近似相等
{
return(outPoint);
}
if (outPointToCenterDistance < Radius) //点在圆内无切点
{
return(null);
}
double pointToTangentPointDistance = Math.Sqrt(Math.Pow(outPointToCenterDistance, 2) - Math.Pow(Radius, 2));
double tangentLineDirection = Center.DirTo(outPoint)
+ Math.Atan(pointToTangentPointDistance / Radius)
* (turnDirection == TurnDirectionType.Left ? 1 : -1);
Point3D p = Center.GetNextPoint(tangentLineDirection, Radius);
if (this.GetRelationShipWithPoint(p) == PointArcRelationShipType.On_ArcSegment)
{
return(p);
}
return(null);
}
/// <summary>
/// 计算传入的射线和当前圆弧位置关系
/// </summary>
/// <param name="line">传入的射线</param>
/// <returns></returns>
public override LineCurveRelationShipType GetCurveCurveRelationShipType(LineSegment line)
{
LineArcRelationShipType type = GetRelationShipwithLine(line);
var dir = line.GetTurnDirection(this.Center);
if (type == LineArcRelationShipType.Apart) //相离
{
if (dir == TurnDirectionType.Left)
{
return(LineCurveRelationShipType.Left);
}
else
{
return(LineCurveRelationShipType.Right);
}
}
else if (type == LineArcRelationShipType.Insert) //和圆弧相交
{
if (this.BeginPoint.Equals(this.EndPoint))
{
return(LineCurveRelationShipType.Intersect);
}
else
{
//1.半圆情况下，可能begin，end点为交点，则onleft或onright
/*
* （1）过begin，end点做直线
* （2）过直线中心做垂线，交圆弧于点p
* （3）判断点p和直线的位置关系
*/
//2.交点存在非begin，end点，则为intersect
TurnDirectionType dirB = line.GetTurnDirection(this.BeginPoint);
TurnDirectionType dirE = line.GetTurnDirection(this.EndPoint);
if (dirB == TurnDirectionType.Stright && dirE == TurnDirectionType.Stright)
{
Point3D lineCenterPoint = new Point3D()
{
X = (this.BeginPoint.X + this.EndPoint.X) / 2, Y = (this.BeginPoint.Y + this.EndPoint.Y) / 2, Z = (this.BeginPoint.Z + this.EndPoint.Z) / 2
};
LineSegment centerLine = new LineSegment(lineCenterPoint, 1, line.GetDirection() + Math.PI / 2);
List <Point3D> listPoint = this.GetIntersectPointsWithLine(centerLine.BeginPoint, centerLine.EndPoint);
if (listPoint != null && listPoint.Count > 0)
{
if (line.GetTurnDirection(listPoint[0]) == TurnDirectionType.Right)
{
return(LineCurveRelationShipType.On_Right);
}
else if (line.GetTurnDirection(listPoint[0]) == TurnDirectionType.Left)
{
return(LineCurveRelationShipType.On_Left);
}
}
}
else
{
return(LineCurveRelationShipType.Intersect);
}
}
}
else if (type == LineArcRelationShipType.InsertWithArc) //和圆弧所在的圆相交
{
if (this.BeginPoint.Equals(this.EndPoint))
{
}
else
{
//只有半圆存在该情况
if (line.GetTurnDirection(this.BeginPoint) == TurnDirectionType.Left)
{
return(LineCurveRelationShipType.Left);
}
else
{
return(LineCurveRelationShipType.Right);
}
}
}
else if (type == LineArcRelationShipType.InsertWithArcSegmentAndArc) //和圆弧，圆弧所在的圆分别相交
{
if (this.BeginPoint.Equals(this.EndPoint))
{
}
else
{
//只有半圆存在该情况
TurnDirectionType dirB = line.GetTurnDirection(this.BeginPoint);
TurnDirectionType dirE = line.GetTurnDirection(this.EndPoint);
if ((dirB == TurnDirectionType.Right && dirE == TurnDirectionType.Left) ||
(dirB == TurnDirectionType.Left && dirE == TurnDirectionType.Right))
{
return(LineCurveRelationShipType.Intersect);
}
else if ((dirB == TurnDirectionType.Right && dirE == TurnDirectionType.Stright) ||
(dirB == TurnDirectionType.Stright && dirE == TurnDirectionType.Right))
{
return(LineCurveRelationShipType.On_Right);
}
else if ((dirB == TurnDirectionType.Left && dirE == TurnDirectionType.Stright) ||
(dirB == TurnDirectionType.Stright && dirE == TurnDirectionType.Left))
{
return(LineCurveRelationShipType.On_Left);
}
}
}
else if (type == LineArcRelationShipType.Tangent) //和圆弧相切
{
if (dir == TurnDirectionType.Left)
{
return(LineCurveRelationShipType.On_Left);
}
else
{
return(LineCurveRelationShipType.On_Right);
}
}
else if (type == LineArcRelationShipType.TangentWithArc) //和圆弧所在的圆相切
{
if (this.BeginPoint.Equals(this.EndPoint))
{
}
else
{
//只有半圆存在该情况
if (dir == TurnDirectionType.Left)
{
return(LineCurveRelationShipType.Left);
}
else
{
return(LineCurveRelationShipType.Right);
}
}
}
return(LineCurveRelationShipType.Others);
}
