用c#实现Sutherland算法

Sutherland算法是一种裁剪线段的算法，可以用于计算机图形学中。以下是用C#实现Sutherland算法的示例代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Drawing;

namespace SutherlandAlgorithm
{
    class Program
    {
        static void Main(string[] args)
        {
            //初始化线段端点
            Point P1 = new Point(50, 100);
            Point P2 = new Point(300, 150);

            //初始化裁剪窗口
            Point V1 = new Point(100, 50);
            Point V2 = new Point(200, 200);

            //使用Sutherland算法裁剪线段
            LineClip(P1, P2, V1, V2);

            Console.ReadKey();
        }

        static void LineClip(Point P1, Point P2, Point V1, Point V2)
        {
            //裁剪窗口边界
            List<Point> clipPoints = new List<Point>();
            clipPoints.Add(V1);
            clipPoints.Add(new Point(V2.X, V1.Y));
            clipPoints.Add(V2);
            clipPoints.Add(new Point(V1.X, V2.Y));

            //初始化起点
            Point S = P1;

            //遍历线段的每个点
            foreach (Point E in new List<Point> { P2 })
            {
                //初始化是否需要裁剪标志
                bool clip = false;

                //初始化裁剪后的点
                Point C = new Point();

                //遍历裁剪窗口的每条边
                for (int i = 0; i < clipPoints.Count; i++)
                {
                    //获取当前边和下一条边
                    Point P0 = clipPoints[i];
                    Point P1 = clipPoints[(i + 1) % clipPoints.Count];

                    //计算裁剪后的点
                    if (Clip(S, E, P0, P1, ref C))
                    {
                        //更新起点和需要裁剪标志
                        S = C;
                        clip = true;
                    }
                }

                //如果需要裁剪，则在裁剪窗口内绘制线段
                if (clip)
                {
                    DrawLine(S, E, Pens.Red);
                }
                //否则在裁剪窗口外绘制线段
                else
                {
                    DrawLine(S, E, Pens.Black);
                }
            }
        }

        static bool Clip(Point S, Point E, Point P0, Point P1, ref Point C)
        {
            //计算线段斜率
            double m = (double)(E.Y - S.Y) / (double)(E.X - S.X);

            //计算交点
            if (E.X > P1.X && S.X < P1.X)
            {
                double y = m * (P1.X - S.X) + S.Y;
                if (y >= P0.Y && y <= P1.Y)
                {
                    C.X = P1.X;
                    C.Y = (int)Math.Round(y);
                    return true;
                }
            }
            if (E.X > P0.X && S.X < P0.X)
            {
                double y = m * (P0.X - S.X) + S.Y;
                if (y >= P0.Y && y <= P1.Y)
                {
                    C.X = P0.X;
                    C.Y = (int)Math.Round(y);
                    return true;
                }
            }
            if (E.Y > P1.Y && S.Y < P1.Y)
            {
                double x = (P1.Y - S.Y) / m + S.X;
                if (x >= P0.X && x <= P1.X)
                {
                    C.X = (int)Math.Round(x);
                    C.Y = P1.Y;
                    return true;
                }
            }
            if (E.Y > P0.Y && S.Y < P0.Y)
            {
                double x = (P0.Y - S.Y) / m + S.X;
                if (x >= P0.X && x <= P1.X)
                {
                    C.X = (int)Math.Round(x);
                    C.Y = P0.Y;
                    return true;
                }
            }

            //如果没有交点，则不需要裁剪
            return false;
        }

        static void DrawLine(Point P1, Point P2, Pen pen)
        {
            using (Graphics graphics = Graphics.FromHwnd(IntPtr.Zero))
            {
                graphics.DrawLine(pen, P1, P2);
            }
        }
    }
}

在上述代码中，LineClip()方法使用Sutherland算法对线段进行裁剪，Clip()方法实现了计算线段与边界的交点。最后，DrawLine()方法用于绘制线段。