/// <summary>
/// 取两点所在直线上的指定长度的向量
/// </summary>
/// <param name="lineStart">线起点</param>
/// <param name="lineEnd">线终点</param>
/// <param name="length">向量长度</param>
/// <returns></returns>
private static VectorD GetVectorOnLineByLength(PointD lineStart, PointD lineEnd, double length)
{
double scale = length / lineStart.DistanceTo(lineEnd);
VectorD vectorOld = lineEnd - lineStart;
return(vectorOld.ScaleBy(scale));
}
public static PointD GetScalePointOnLine(PointD lineStart, PointD lineEnd, double scale)
{
VectorD vLine = lineEnd - lineStart;
PointD result = lineStart + vLine.ScaleBy(scale);
return(result);
}
/// <summary>
/// 以半径为基准作为获取过渡圆弧
/// </summary>
/// <param name="lineStart">线起点</param>
/// <param name="intersection">线与原始圆弧交点</param>
/// <param name="oriArcCenter">原始圆弧圆心</param>
/// <param name="transitionR">过渡圆弧半径</param>
/// <param name="oriArcClockwise">原始圆弧方向</param>
/// <returns>过渡圆弧的起点、圆心、终点</returns>
public static List <PointD> GetLineToArcTransitionArcByR(PointD lineStart, PointD intersection, PointD oriArcCenter, double transitionR, double oriArcClockwise)
{
List <PointD> points = new List <PointD>();
PointD transitionArcCenter, newLineEnd, newArcStart;
double angle = GetAngleOfTwoLine(lineStart, intersection, oriArcCenter);
VectorD vArcS = intersection - oriArcCenter;
double oriR = vArcS.Length;
VectorD vArcSRotate1;
if (oriArcClockwise == 1)
{
vArcSRotate1 = vArcS.Rotate(-90);
}
else
{
vArcSRotate1 = vArcS.Rotate(90);
}
if (angle != Math.PI)
{
//求原始圆弧半径
double len1;
if (GetAngleOfTwoLine(lineStart, intersection, (intersection + vArcSRotate1)) > (Math.PI / 2))
{
len1 = oriR * Math.Sin(Math.PI - angle) + transitionR;
}
else
{
len1 = oriR * Math.Sin(Math.PI - angle) - transitionR;
}
double len2 = Math.Sqrt((oriR + transitionR) * (oriR + transitionR) - len1 * len1);
PointD footPoint = MathUtils.GetFootPoint(oriArcCenter, lineStart, intersection);
VectorD vLenTemp = (footPoint - oriArcCenter);
VectorD vLen1 = vLenTemp.ScaleBy(len1 / vLenTemp.Length);
VectorD vLine = lineStart - intersection;
VectorD vLen2 = vLine.ScaleBy(len2 / vLine.Length);
transitionArcCenter = oriArcCenter + vLen1 + vLen2;
newLineEnd = MathUtils.GetFootPoint(transitionArcCenter, lineStart, intersection);
newArcStart = transitionArcCenter + (oriArcCenter - transitionArcCenter).ScaleBy(transitionR / (oriR + transitionR));
}
else
{
double len1 = transitionR;
double len2 = Math.Sqrt((oriR + transitionR) * (oriR + transitionR) - len1 * len1);
VectorD vLen2 = vArcS.ScaleBy(len2 / oriR);
newLineEnd = oriArcCenter + vLen2;
VectorD vLen1 = vArcSRotate1.ScaleBy(transitionR / vArcSRotate1.Length);
transitionArcCenter = newLineEnd + vLen1;
newArcStart = transitionArcCenter + (oriArcCenter - transitionArcCenter).ScaleBy(transitionR / (transitionR + oriR));
}
points.Add(newLineEnd);
points.Add(transitionArcCenter);
points.Add(newArcStart);
return(points);
}
/// <summary>
/// 获取角平分线上一点
/// </summary>
/// <param name="start"></param>
/// <param name="middle"></param>
/// <param name="end"></param>
/// <returns></returns>
private static PointD GetAPointOnAngleBiscetor(PointD start, PointD middle, PointD end)
{
double len1 = start.DistanceTo(middle);
double len2 = middle.DistanceTo(end);
double scale = len1 / (len1 + len2);
// 角平分线与对边交点
PointD point1 = new PointD();
VectorD vector1 = end - start;
point1 = start + vector1.ScaleBy(scale);
return(point1);
}
/// <summary>
/// 返回两线段交点 （实际情况不需要考虑不相交情况）
/// </summary>
/// <param name="line1Start">线1起点</param>
/// <param name="line1End">线1终点</param>
/// <param name="line2Start">线2起点</param>
/// <param name="line2End">线2终点</param>
/// <returns></returns>
private static PointD GetIntersection(PointD line1Start, PointD line1End, PointD line2Start, PointD line2End)
{
double x1 = line1Start.X;
double y1 = line1Start.Y;
double x2 = line1End.X;
double y2 = line1End.Y;
double x3 = line2Start.X;
double y3 = line2Start.Y;
double x4 = line2End.X;
double y4 = line2End.Y;
double t = ((x2 - x1) * (y3 - y1) - (x3 - x1) * (y2 - y1)) / ((x2 - x1) * (y3 - y4) - (x3 - x4) * (y2 - y1));
VectorD temp = line2End - line2Start;
PointD result = line2Start + temp.ScaleBy(t);
return(result);
}