图形技术（局部图片放大）

核心代码：

Cursor myCursor = new Cursor(@"C:\WINDOWS\Cursors\aero_cross.cur"); //自定义鼠标
  Image myImage;

//选择图片

 private void button1_Click(object sender, EventArgs e)
        {
            openFileDialog1.Filter = "*.jpg,*.jpeg,*.bmp,*.gif,*.ico,*.png,*.tif,*.wmf|*.jpg;*.jpeg;*.bmp;*.gif;*.ico;*.png;*.tif;*.wmf";
            openFileDialog1.ShowDialog();
            myImage = System.Drawing.Image.FromFile(openFileDialog1.FileName);
            pictureBox1.Image = myImage;
            pictureBox1.Height = myImage.Height;
            pictureBox1.Width = myImage.Width;
        }

//鼠标经过的地方放大

        private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
        {
            try
            {
                Cursor.Current = myCursor;
                Graphics graphics = pictureBox1.CreateGraphics();
                Rectangle sourceRectangle = new Rectangle(e.X - 10, e.Y - 10, 20, 20); //要放大的区域
                Rectangle destRectangle = new Rectangle(e.X - 20, e.Y - 20, 40, 40);
                graphics.DrawImage(myImage, destRectangle, sourceRectangle, GraphicsUnit.Pixel);
            }
            catch
            { }
        }