Masuit.Tools/Masuit.Tools.Abstractions/Models/Circle.cs

using Masuit.Tools.Maths;
using System;

namespace Masuit.Tools.Models;

/// <summary>
/// 圆形
/// </summary>
public class Circle
{
    /// <summary>
    /// 圆形
    /// </summary>
    /// <param name="center">圆心坐标</param>
    /// <param name="radius">半径</param>
    public Circle(Point2D center, double radius)
    {
        Center = center;
        Radius = radius;
        if (radius < 0)
        {
            throw new ArgumentException("半径不能为负数", nameof(radius));
        }
    }

    /// <summary>
    /// 圆心坐标
    /// </summary>
    public Point2D Center { get; }

    /// <summary>
    /// 半径
    /// </summary>
    public double Radius { get; }

    /// <summary>
    /// 是否相交
    /// </summary>
    /// <param name="that"></param>
    /// <returns></returns>
    public bool IsCrossWith(Circle that)
    {
        var dis = Math.Sqrt(Math.Pow(that.Center.X - Center.X, 2) + Math.Pow(that.Center.Y - Center.Y, 2));
        return that.Radius - Radius < dis && dis < that.Radius + Radius;
    }

    /// <summary>
    /// 是否相切
    /// </summary>
    /// <param name="that"></param>
    /// <returns></returns>
    public bool IsIntersectWith(Circle that)
    {
        var dis = Math.Sqrt(Math.Pow(that.Center.X - Center.X, 2) + Math.Pow(that.Center.Y - Center.Y, 2));
        return Math.Abs(that.Radius - Radius - dis) < 1e-7 || Math.Abs(dis - (that.Radius + Radius)) < 1e-7;
    }

    /// <summary>
    /// 是否相离
    /// </summary>
    /// <param name="that"></param>
    /// <returns></returns>
    public bool IsSeparateWith(Circle that)
    {
        return !IsCrossWith(that) && !IsIntersectWith(that);
    }
}