底片效果显示图像，类似旧式相机的底片一样

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace NegativeImage
{
public partial class Frm_Main : Form
{
public Frm_Main()
{
InitializeComponent();
}

private void button2_Click(object sender, EventArgs e)
{
//打图像文件
OpenFileDialog openFileDialog = new OpenFileDialog();
openFileDialog.Filter = "图像文件(JPeg, Gif, Bmp, etc.)|*.jpg;*.jpeg;*.gif;*.bmp;*.tif; *.tiff; *.png| JPeg 图像文件(*.jpg;*.jpeg)|*.jpg;*.jpeg |GIF 图像文件(*.gif)|*.gif |BMP图像文件(*.bmp)|*.bmp|Tiff图像文件(*.tif;*.tiff)|*.tif;*.tiff|Png图像文件(*.png)| *.png |所有文件(*.*)|*.*";
if (openFileDialog.ShowDialog() == DialogResult.OK)//判断是否选择了文件
{
Bitmap MyBitmap = new Bitmap(openFileDialog.FileName);
this.pictureBox1.Image = MyBitmap;
}
}

private void button1_Click(object sender, EventArgs e)
{
try
{
int Height = this.pictureBox1.Image.Height;//获取图片高度
int Width = this.pictureBox1.Image.Width;//获取图片宽度
Bitmap newbitmap = new Bitmap(Width, Height);//实例化位图对象
Bitmap oldbitmap = (Bitmap)this.pictureBox1.Image;//获取原图
Color pixel;//定义一个Color结构
//遍历图片的每个位置
for (int x = 1; x < Width; x )
{
for (int y = 1; y < Height; y )
{
int r, g, b;//定义3个变量，用来记录指定点的R\G\B值
pixel = oldbitmap.GetPixel(x, y);//获取指定点的像素值
r = 255 - pixel.R;//记录R值
g = 255 - pixel.G;//记录G值
b = 255 - pixel.B;//记录B值
newbitmap.SetPixel(x, y, Color.FromArgb(r, g, b));//为指定点重新着色
}
}
this.pictureBox1.Image = newbitmap;//显示底片效果的图像
}
catch (Exception ex)
{
MessageBox.Show(ex.Message, "信息提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
}
}
}
}