[转]计算两点间的角度

/// <summary>

/// 计算两点间的角度

/// </summary>

/// <param name="AOrigin">原点坐标</param>

/// <param name="APoint">参考点坐标</param>

/// <param name="APoint">离心率</param>

/// <returns>返回两点间的角度</returns>

private double PointToAngle(Point AOrigin, Point APoint, double AEccentricity)

{

if (APoint.X == AOrigin.X)

if (APoint.Y > AOrigin.Y)

return Math.PI * 0.5;

else return Math.PI * 1.5;

else if (APoint.Y == AOrigin.Y)

if (APoint.X > AOrigin.X)

return 0;

else return Math.PI;

else

{

double Result = Math.Atan((AOrigin.Y - APoint.Y) /

(AOrigin.X - APoint.X) * AEccentricity);

if ((APoint.X < AOrigin.X) && (APoint.Y > AOrigin.Y))

return Result + Math.PI;

else if ((APoint.X < AOrigin.X) && (APoint.Y < AOrigin.Y))

return Result + Math.PI;

else if ((APoint.X > AOrigin.X) && (APoint.Y < AOrigin.Y))

return Result + 2 * Math.PI;

else return Result;

}

} /* PointToAngle */