原理就是截取游戏界面,然后图像对比.
用到的类:ScreenShot截图类,来自网络,并参考aardio的截图代码做了修改,使之更好用

using System;
using System.Runtime.InteropServices;
using System.Drawing;
using System.Drawing.Imaging;
using System.Windows.Forms;

namespace QQ找茬助手
{
class ScreenShot
{
/// <summary>
/// Creates an Image object containing a screen shot of the entire desktop?
/// </summary>
/// <returns></returns>
public Image CaptureScreen()
{
return CaptureWindow(User32.GetDesktopWindow());
}

public Image CaptureWindow(IntPtr handle)
{
MessageBox.Show("CaptureScreen()");
return CaptureWindow(handle,0,0,0,0);
}
/// <summary>
/// Creates an Image object containing a screen shot of a specific window?
/// </summary>
/// <param name="handle">The handle to the window. (In windows forms, this is obtained by the Handle property)</param>
/// <returns></returns>
public Image CaptureWindow(IntPtr handle,int x=0,int y=0,int w=0,int h=0)
{
// get te hDC of the target window
IntPtr hdcSrc = User32.GetWindowDC(handle);
// get the size
User32.RECT windowRect = new User32.RECT();
User32.GetWindowRect(handle, ref windowRect);
int width = w > 0 ? w : (windowRect.right - windowRect.left - x);
int height = h > 0 ? h : (windowRect.bottom - windowRect.top - y);
// create a device context we can copy to
IntPtr hdcDest = GDI32.CreateCompatibleDC(hdcSrc);
// create a bitmap we can copy it to,
// using GetDeviceCaps to get the width/height
IntPtr hBitmap = GDI32.CreateCompatibleBitmap(hdcSrc, width, height);
// select the bitmap object
IntPtr hOld = GDI32.SelectObject(hdcDest, hBitmap);
// bitblt over
GDI32.BitBlt(hdcDest, 0, 0, width, height, hdcSrc, x, y, GDI32.SRCCOPY | GDI32.CAPTUREBLT);
// restore selection
GDI32.SelectObject(hdcDest, hOld);
// clean up
GDI32.DeleteDC(hdcDest);
User32.ReleaseDC(handle, hdcSrc);
// get a .NET image object for it
Image img = Image.FromHbitmap(hBitmap);
// free up the Bitmap object
GDI32.DeleteObject(hBitmap);
return img;
}
/// <summary>
/// Captures a screen shot of a specific window, and saves it to a file?
/// </summary>
/// <param name="handle"></param>
/// <param name="filename"></param>
/// <param name="format"></param>
public void CaptureWindowToFile(IntPtr handle, string filename, ImageFormat format)
{
Image img = CaptureWindow(handle);
img.Save(filename, format);
}
/// <summary>
/// Captures a screen shot of the entire desktop, and saves it to a file?
/// </summary>
/// <param name="filename"></param>
/// <param name="format"></param>
public void CaptureScreenToFile(string filename, ImageFormat format)
{
Image img = CaptureScreen();
img.Save(filename, format);
}

/// <summary>
/// Helper class containing Gdi32 API functions
/// </summary>
private class GDI32
{

public const int SRCCOPY = 0x00CC0020; // BitBlt dwRop parameter
public const int CAPTUREBLT = 0x40000000;
[DllImport("gdi32.dll")]
public static extern bool BitBlt(IntPtr hObject, int nXDest, int nYDest,
int nWidth, int nHeight, IntPtr hObjectSource,
int nXSrc, int nYSrc, int dwRop);
[DllImport("gdi32.dll")]
public static extern IntPtr CreateCompatibleBitmap(IntPtr hDC, int nWidth,
int nHeight);
[DllImport("gdi32.dll")]
public static extern IntPtr CreateCompatibleDC(IntPtr hDC);
[DllImport("gdi32.dll")]
public static extern bool DeleteDC(IntPtr hDC);
[DllImport("gdi32.dll")]
public static extern bool DeleteObject(IntPtr hObject);
[DllImport("gdi32.dll")]
public static extern IntPtr SelectObject(IntPtr hDC, IntPtr hObject);
}

/// <summary>
/// Helper class containing User32 API functions
/// </summary>
private class User32
{
[StructLayout(LayoutKind.Sequential)]
public struct RECT
{
public int left;
public int top;
public int right;
public int bottom;
}
[DllImport("user32.dll")]
public static extern IntPtr GetDesktopWindow();
[DllImport("user32.dll")]
public static extern IntPtr GetWindowDC(IntPtr hWnd);
[DllImport("user32.dll")]
public static extern IntPtr ReleaseDC(IntPtr hWnd, IntPtr hDC);
[DllImport("user32.dll")]
public static extern IntPtr GetWindowRect(IntPtr hWnd, ref RECT rect);
}
}
}

逻辑代码:

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

namespace QQ找茬助手
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
[DllImport("user32.dll")]
private extern static IntPtr FindWindow(string lpClassName, string lpWindowName);
[DllImport("user32.dll")]
private extern static bool SetWindowPos(IntPtr hwnd, IntPtr hwndlnsertAfter, int X, int Y, int cx, int cy, int Flags);

private void Form1_Load(object sender, EventArgs e)
{
timer1.Enabled = true;
}

private void timer1_Tick(object sender, EventArgs e)
{
toolStripStatusLabel2.Text = DateTime.Now.ToLongTimeString();
Point cp = pictureBox1.PointToClient(new Point(MousePosition.X, MousePosition.Y ));
string pos = string.Format("{0},{1}", cp.X,cp.Y);
toolStripStatusLabel4.Text = pos;
}

private void button1_Click(object sender, EventArgs e)
{
IntPtr hwnd = FindWindow("#32770", "大家来找茬");
if (hwnd.ToInt32()==0)
{
MessageBox.Show("游戏未打开");
return;
}
SetWindowPos(hwnd, IntPtr.Zero, 0, 0, 0, 0, 0x1 | 0x4);
Thread.Sleep(80);
//Application.DoEvents();
ScreenShot ss = new ScreenShot();
Image Lwindow = ss.CaptureWindow(hwnd, 10, 185, 381, 287);
Image Rwindow = ss.CaptureWindow(hwnd, 403, 185, 381, 287);
Bitmap left = new Bitmap(Lwindow);
Bitmap right = new Bitmap(Rwindow);
Color n = Color.FromName("Green");
for (int i=1;i<left.Width;i++)
{
for (int j=1;j<left.Height;j++)
{
Color Lcolor = left.GetPixel(i,j);
Color Rcolor = right.GetPixel(i, j);
float Ln = Lcolor.GetHue();
float Rn = Rcolor.GetHue();
if (Ln!=Rn)
{
right.SetPixel(i, j, n);
}
}
}
pictureBox1.Image = right;
//left.Dispose();
//right.Dispose();
//Lwindow.Dispose();
//Rwindow.Dispose();
}

private void pictureBox1_Click(object sender, EventArgs e)
{

}
}
}