三阶贝塞尔曲线 C# 代码

以下是一个简单的C#代码示例，用于绘制三阶贝塞尔曲线：

using System;
using System.Drawing;
using System.Windows.Forms;

public class BezierCurveForm : Form
{
    private Point[] controlPoints;

    public BezierCurveForm()
    {
        controlPoints = new Point[4];
        controlPoints[0] = new Point(50, 200);
        controlPoints[1] = new Point(150, 100);
        controlPoints[2] = new Point(250, 300);
        controlPoints[3] = new Point(350, 200);

        this.Paint += BezierCurveForm_Paint;
    }

    private void BezierCurveForm_Paint(object sender, PaintEventArgs e)
    {
        Graphics g = e.Graphics;
        Pen pen = new Pen(Color.Red, 2);

        // 绘制控制点
        for (int i = 0; i < controlPoints.Length; i++)
        {
            g.FillEllipse(Brushes.Black, controlPoints[i].X - 3, controlPoints[i].Y - 3, 6, 6);
        }

        // 绘制贝塞尔曲线
        for (float t = 0; t <= 1; t += 0.01f)
        {
            Point curvePoint = CalculateBezierPoint(t);
            g.DrawEllipse(pen, curvePoint.X, curvePoint.Y, 1, 1);
        }
    }

    private Point CalculateBezierPoint(float t)
    {
        float u = 1 - t;
        float tt = t * t;
        float uu = u * u;
        float uuu = uu * u;
        float ttt = tt * t;

        Point p = new Point();

        p.X = (int)(uuu * controlPoints[0].X);
        p.X += (int)(3 * uu * t * controlPoints[1].X);
        p.X += (int)(3 * u * tt * controlPoints[2].X);
        p.X += (int)(ttt * controlPoints[3].X);

        p.Y = (int)(uuu * controlPoints[0].Y);
        p.Y += (int)(3 * uu * t * controlPoints[1].Y);
        p.Y += (int)(3 * u * tt * controlPoints[2].Y);
        p.Y += (int)(ttt * controlPoints[3].Y);

        return p;
    }

    public static void Main()
    {
        Application.Run(new BezierCurveForm());
    }
}

这段代码创建了一个窗体，并在窗体上绘制了一个三阶贝塞尔曲线。控制点用黑色圆圈表示，曲线用红色细线绘制。你可以根据需要修改控制点的位置来调整曲线的形状。