using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Linq;using System.Text;using System.Windows.Forms;using System.Drawing.Imaging;namespace WindowsFormsApplication4{    public partial class Form1 : Form    {        public Form1()        {            InitializeComponent();        }        private void button1_Click(object sender, EventArgs e)        {            OpenFileDialog dig = new OpenFileDialog();            if (dig.ShowDialog() == DialogResult.OK)                pictureBox1.Image = Image.FromFile(dig.FileName);        }        unsafe private void button2_Click(object sender, EventArgs e)        {            Bitmap bitmap =(Bitmap)pictureBox1.Image.Clone();   //创建副本，避免操作原图像            Rectangle rect = new Rectangle(0, 0, bitmap.Width, bitmap.Height);            BitmapData bmpdata= bitmap.LockBits(rect, ImageLockMode.ReadWrite,bitmap.PixelFormat);            byte* pix = (byte*)bmpdata.Scan0;            if (bitmap.PixelFormat==PixelFormat.Format8bppIndexed)  //是否为灰度图            {                for (int i = 0; i < bmpdata.Height; i++)                {                    for (int j = 0; j < bmpdata.Width; j++)                    {                        pix[0] = (byte)(255 - pix[0]);      //反色                        pix++;                    }                }            }            else            {                for (int i = 0; i < bmpdata.Height;i++ )                {                    for (int j = 0; j < bmpdata.Width;j++ )                    {                        pix[0] = (byte)(255 - pix[0]);      //反色                        pix[1] = (byte)(255 - pix[1]);                        pix[2] = (byte)(255 - pix[2]);                        pix = pix + 3;                    }                }            }             bitmap.UnlockBits(bmpdata);            pictureBox2.Image=bitmap;        }    }}