public partial class OpertaionImg : 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 = ;      //缩放步长

         public OpertaionImg()

         {

             InitializeComponent();

         }

         private void btnChoise_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 = ;

             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;

             picturePhoto.Image = myBmp;

             picturePhoto.SizeMode = PictureBoxSizeMode.Zoom; //设置picturebox为缩放模式

             picturePhoto.Width = myBmp.Width;

             picturePhoto.Height = myBmp.Height;

         }

         private void picturePhoto_MouseDown(object sender, MouseEventArgs e)

         {

             if (e.Button == MouseButtons.Left)

             {

                 mouseDownPoint.X = Cursor.Position.X;

                 mouseDownPoint.Y = Cursor.Position.Y;

                 isMove = true;

                 picturePhoto.Focus();

             }

         }

         private void picturePhoto_MouseUp(object sender, MouseEventArgs e)

         {

             if (e.Button == MouseButtons.Left)

             {

                 isMove = false;

             }

         }

         private void picturePhoto_MouseMove(object sender, MouseEventArgs e)

         {

             picturePhoto.Focus();

             if (isMove)

             {

                 int x, y;

                 int moveX, moveY;

                 moveX = Cursor.Position.X - mouseDownPoint.X;

                 moveY = Cursor.Position.Y - mouseDownPoint.Y;

                 x = picturePhoto.Location.X + moveX;

                 y = picturePhoto.Location.Y + moveY;

                 picturePhoto.Location = new Point(x, y);

                 mouseDownPoint.X = Cursor.Position.X;

                 mouseDownPoint.Y = Cursor.Position.Y;

             }

         }

         private void picturePhoto_MouseWheel(object sender, MouseEventArgs e)

         {

             int x = e.Location.X;

             int y = e.Location.Y;

             int ow = picturePhoto.Width;

             int oh = picturePhoto.Height;

             int VX, VY;

             if (e.Delta > )

             {

                 picturePhoto.Width += zoomStep;

                 picturePhoto.Height += zoomStep;

                 PropertyInfo pInfo = picturePhoto.GetType().GetProperty("ImageRectangle", BindingFlags.Instance |BindingFlags.NonPublic);

                 Rectangle rect = (Rectangle)pInfo.GetValue(picturePhoto, null);

                 picturePhoto.Width = rect.Width;

                 picturePhoto.Height = rect.Height;

             }

             if (e.Delta < )

             {

                 if (picturePhoto.Width < myBmp.Width / )

                     return;

                 picturePhoto.Width -= zoomStep;

                 picturePhoto.Height -= zoomStep;

                 PropertyInfo pInfo = picturePhoto.GetType().GetProperty("ImageRectangle", BindingFlags.Instance |BindingFlags.NonPublic);

                 Rectangle rect = (Rectangle)pInfo.GetValue(picturePhoto, null);

                 picturePhoto.Width = rect.Width;

                 picturePhoto.Height = rect.Height;

             }

             VX = (int)((double)x * (ow - picturePhoto.Width) / ow);

             VY = (int)((double)y * (oh - picturePhoto.Height) / oh);

             picturePhoto.Location = new Point(picturePhoto.Location.X + VX, picturePhoto.Location.Y + VY);

         }

         private void btnSave_Click(object sender, EventArgs e)

         {

             SaveFileDialog sa = new SaveFileDialog();

             //设置文件类型

             sa.Filter = "图片文件（*.png）|*.png";

             //设置默认文件类型显示顺序

             sa.FilterIndex = ;

             if (sa.ShowDialog() == DialogResult.OK)

             {

                 Bitmap bit = new Bitmap(picturePhoto.Width, picturePhoto.Height);//实例化一个和窗体一样大的bitmap

                 Graphics g = Graphics.FromImage(bit);

                 g.CompositingQuality = CompositingQuality.HighQuality;//质量设为最高

                 // g.CopyFromScreen(this.Left, this.Top, 0, 0, new Size(panel2.Width, panel2.Height));//保存整个窗体为图片

                 g.CopyFromScreen(picturePhoto.PointToScreen(Point.Empty), Point.Empty, picturePhoto.Size);//只保存某个控件（这里是panel游戏区）

                 bit.Save(sa.FileName);//默认保存格式为PNG，保存成jpg格式质量不是很好

             }

         }

     }