WinForm实现的图片拖拽与缩放功能示例

using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Linq;using System.Text;using System.Threading.Tasks;using System.Windows.Forms;using System.Reflection;namespace 图像平移缩放{  public partial class Form1 : Form  {    Bitmap myBmp;    Point mouseDownPoint = new Point(); //记录拖拽过程鼠标位置    bool isMove = false;  //判断鼠标在picturebox上移动时，是否处于拖拽过程(鼠标左键是否按下)    int zoomStep = 20;   //缩放步长    public Form1()    {      InitializeComponent();    }    //图片上传    private void button1_Click(object sender, EventArgs e)    {      string filename = "";      OpenFileDialog dlg = new OpenFileDialog();      dlg.Filter = "Tiff文件|*.tif|Bmp文件|*.bmp|Erdas img文件|*.img|EVNI文件|*.hdr|jpeg文件|*.jpg|raw文件|*.raw|vrt文件|*.vrt|所有文件|*.*";      dlg.FilterIndex = 8;      if (dlg.ShowDialog() == DialogResult.OK)      {        filename = dlg.FileName;      }      if (filename == "")      {        return;      }      myBmp = new Bitmap(filename);      if (myBmp == null)      {        MessageBox.Show("读取失败");        return;      }      textBox1.Text = filename;      pictureBox1.Image = myBmp;      pictureBox1.SizeMode = PictureBoxSizeMode.Zoom; //设置picturebox为缩放模式      pictureBox1.Width = myBmp.Width;      pictureBox1.Height = myBmp.Height;    }    //鼠标按下功能    private void pictureBox1_MouseDown(object sender, MouseEventArgs e)    {      if (e.Button == MouseButtons.Left)      {        mouseDownPoint.X = Cursor.Position.X;        mouseDownPoint.Y = Cursor.Position.Y;        isMove = true;        pictureBox1.Focus();      }    }    //鼠标松开功能    private void pictureBox1_MouseUp(object sender, MouseEventArgs e)    {      if (e.Button == MouseButtons.Left)      {        isMove = false;      }    }    //鼠标移动功能    private void pictureBox1_MouseMove(object sender, MouseEventArgs e)    {      pictureBox1.Focus();      if (isMove)      {        int x, y;        int moveX, moveY;        moveX = Cursor.Position.X - mouseDownPoint.X;        moveY = Cursor.Position.Y - mouseDownPoint.Y;        x = pictureBox1.Location.X + moveX;        y = pictureBox1.Location.Y + moveY;        pictureBox1.Location = new Point(x, y);        mouseDownPoint.X = Cursor.Position.X;        mouseDownPoint.Y = Cursor.Position.Y;      }    }    //鼠标滚轮滚动功能    private void pictureBox1_MouseWheel(object sender, MouseEventArgs e)    {      int x = e.Location.X;      int y = e.Location.Y;      int ow = pictureBox1.Width;      int oh = pictureBox1.Height;      int VX, VY;      if (e.Delta > 0)      {        pictureBox1.Width += zoomStep;        pictureBox1.Height += zoomStep;        PropertyInfo pInfo = pictureBox1.GetType().GetProperty("ImageRectangle", BindingFlags.Instance |          BindingFlags.NonPublic);        Rectangle rect = (Rectangle)pInfo.GetValue(pictureBox1, null);        pictureBox1.Width = rect.Width;        pictureBox1.Height = rect.Height;      }      if (e.Delta < 0)      {        if (pictureBox1.Width < myBmp.Width / 10)          return;        pictureBox1.Width -= zoomStep;        pictureBox1.Height -= zoomStep;        PropertyInfo pInfo = pictureBox1.GetType().GetProperty("ImageRectangle", BindingFlags.Instance |          BindingFlags.NonPublic);        Rectangle rect = (Rectangle)pInfo.GetValue(pictureBox1, null);        pictureBox1.Width = rect.Width;        pictureBox1.Height = rect.Height;      }      VX = (int)((double)x * (ow - pictureBox1.Width) / ow);      VY = (int)((double)y * (oh - pictureBox1.Height) / oh);      pictureBox1.Location = new Point(pictureBox1.Location.X + VX, pictureBox1.Location.Y + VY);    }    private void panel2_MouseDown(object sender, MouseEventArgs e)    {      if (e.Button == MouseButtons.Left)      {        mouseDownPoint.X = Cursor.Position.X;        mouseDownPoint.Y = Cursor.Position.Y;        isMove = true;      }    }    private void panel2_MouseUp(object sender, MouseEventArgs e)    {      if (e.Button == MouseButtons.Left)      {        isMove = false;      }    }    private void panel2_MouseMove(object sender, MouseEventArgs e)    {      panel2.Focus();      if (isMove)      {        int x, y;        int moveX, moveY;        moveX = Cursor.Position.X - mouseDownPoint.X;        moveY = Cursor.Position.Y - mouseDownPoint.Y;        x = pictureBox1.Location.X + moveX;        y = pictureBox1.Location.Y + moveY;        pictureBox1.Location = new Point(x, y);        mouseDownPoint.X = Cursor.Position.X;        mouseDownPoint.Y = Cursor.Position.Y;      }    }  }}

//// pictureBox1//this.pictureBox1.BackColor = System.Drawing.Color.White;this.pictureBox1.Location = new System.Drawing.Point(20, 20);this.pictureBox1.Margin = new System.Windows.Forms.Padding(2, 2, 2, 2);this.pictureBox1.Name = "pictureBox1";this.pictureBox1.Size = new System.Drawing.Size(67, 34);this.pictureBox1.TabIndex = 0;this.pictureBox1.TabStop = false;this.pictureBox1.MouseDown += new System.Windows.Forms.MouseEventHandler(this.pictureBox1_MouseDown);this.pictureBox1.MouseMove += new System.Windows.Forms.MouseEventHandler(this.pictureBox1_MouseMove);this.pictureBox1.MouseUp += new System.Windows.Forms.MouseEventHandler(this.pictureBox1_MouseUp);this.pictureBox1.MouseWheel += new System.Windows.Forms.MouseEventHandler(this.pictureBox1_MouseWheel);