C#使用Winform 写一个 读取展示图片的范例，该范例中的图片控件需要支持放大缩小及画图文字功能

在C# Winform中，你可以使用PictureBox控件来显示和操作图片，并结合Zooming和Drawing功能。以下是一个基本的范例，展示了如何做到这一点：

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

public partial class MainForm : Form
{
    private PictureBox pictureBox1;
    private bool isZoomed = false;

    public MainForm()
    {
        InitializeComponent();

        // 初始化PictureBox
        pictureBox1 = new PictureBox();
        pictureBox1.Dock = DockStyle.Fill;
        pictureBox1.SizeMode = PictureBoxSizeMode.StretchImage; // 初始设置成填充模式
        Controls.Add(pictureBox1);
        
        // 加载图片并设置鼠标滚轮事件处理图片缩放
        pictureBox1.ImageLocation = "path_to_your_image.jpg";
        pictureBox1.MouseWheel += pictureBox_MouseWheel;
    }

    private void pictureBox_MouseWheel(object sender, MouseEventArgs e)
    {
        if (isZoomed)
            UnzoomPictureBox();
        else
            ZoomPictureBox(e.Delta > 0); // 滚轮向上放大，向下缩小
    }

    private void ZoomPictureBox(bool zoomIn)
    {
        isZoomed = true;
        int zoomFactor = 1.2f; // 缩放因子

        if (zoomIn)
        {
            Size newSize = pictureBox1.Size * zoomFactor;
            pictureBox1.Size = newSize;
            pictureBox1.Location = new Point((pictureBox1.Width - newSize.Width) / 2, (pictureBox1.Height - newSize.Height) / 2);
        }
        else
        {
            pictureBox1.Size = pictureBox1.PreviousSize; // 如果已经放大，则恢复原尺寸
        }
    }

    private void UnzoomPictureBox()
    {
        isZoomed = false;
        pictureBox1.Size = pictureBox1.PreviousSize; // 回到原始大小
    }

    // 添加一个用于画图的文字功能，例如使用Pen和Graphics对象
    protected override void OnPaint(PaintEventArgs e)
    {
        base.OnPaint(e);

        using (var pen = new Pen(Color.Black, 2))
        {
            // 示例：在图片中心绘制一条线
            int centerX = pictureBox1.ClientSize.Width / 2;
            int centerY = pictureBox1.ClientSize.Height / 2;
            e.Graphics.DrawLine(pen, centerX, 0, centerX, pictureBox1.ClientSize.Height);
        }
    }
}