C# 实现Bezier曲线（vs2008）

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

 

namespace doBezier

{

    public partial class Form1 : Form

    {

        PointF[] p = new PointF[100];   //存储控制点坐标

        int count;                    //记录已输入的控制点个数

        Graphics g;                  //GDI 对象

 

        public Form1()

        {

            InitializeComponent();

            g = CreateGraphics();

            count = 0;

        }

 

        private void Form1_Load(object sender, EventArgs e)

        {

 

        }

 

        private void Form1_MouseClick(object sender, MouseEventArgs e)

        {

            if (e.Button == MouseButtons.Left)

            {

                if (count == 0)      //如果输入的是第一个点，先清空窗口

                    g.Clear(BackColor);

 

                g.FillRectangle(Brushes.Red, e.X - 2, e.Y - 2, 4, 4);  //输出一个标记

                p[count] = new PointF(e.X, e.Y);                 //存储

                count ;                                    //记录输入控制点个数

                return;

            }

            else

            {

                PointF q1 = new PointF();

                PointF q2 = new PointF();

                double u;

 

                for (int i = 0; i <= 100; i )//生成100个点并连成折线

                {

                    u = (double)i / 100.0;

                    if (i == 0)

                    {

                        q1 = deCasteljau(u);

                    }

                    else

                    {

                        q2 = deCasteljau(u);

                        g.DrawLine(Pens.Black, q1, q2);

                        q1.X = q2.X;

                        q1.Y = q2.Y;

                    }

                }

                count = 0;

                return;

            }

        }

 

        PointF deCasteljau(double u)   //曲线参数为u，函数返回一个二维点 

        {

            int i, k;

            //以下将控制点数组p[]，复制到数组q[]

            PointF[] q = new PointF[100];

            for (i = 0; i < count; i )

            {

                q[i].X = p[i].X;

                q[i].Y = p[i].Y;

            }

            //以下用de Casteljau割角算法计算bezier曲线上参数点u对应的x,y，

            //计算完成后，结果存储在q[0]

            for (k = 1; k < count; k )

                for (i = 0; i < count - k; i )

                {

                    q[i].X = (float)(1.0 - u) * q[i].X   (float)u * q[i   1].X;

                    q[i].Y = (float)(1.0 - u) * q[i].Y   (float)u * q[i   1].Y;

                }

            return new PointF(q[0].X, q[0].Y);

        }

 

        private void Form1_Paint(object sender, PaintEventArgs e)

        {

 

        }

    }

}