以前本人用C#制作过一些小游戏的外挂，其中一步最重要的原理是截取电脑的屏幕，然后分析关键像素点的信息。现在用C++重用这些程序时，在截屏上遇到一些问题，现在终于解决了，贴出自己整理后的代码。
分为win32代码和MFC代码，如下
1 void Test_captrueScreenwin32() 2 { 3 HDC hDesktopDc=CreateDC(_T("DISPLAY"), NULL, NULL, NULL); 4 int width=GetDeviceCaps(hDesktopDc,HORZRES); 5 int height=GetDeviceCaps(hDesktopDc,VERTRES); 6 7 HBITMAP hMemBmp; 8 HDC hMemDc; 9 hMemBmp= CreateCompatibleBitmap(hDesktopDc,width,height); 10 hMemDc=CreateCompatibleDC(hDesktopDc); 11 ::SelectObject(hMemDc,hMemBmp); 12 13 BitBlt(hMemDc,0,0,width,height,hDesktopDc,0,0,SRCCOPY); //一定得先复制到内存中去 14 15 BITMAP bmp; 16 ::GetObject(hMemBmp,sizeof(bmp),&bmp); //从HBITMAP 到BITMAP 17 18 BITMAPINFOHEADER m_bihScreen; 19 ZeroMemory(&m_bihScreen, sizeof(BITMAPINFOHEADER));//位图信息头 20 m_bihScreen.biBitCount = bmp.bmBitsPixel;//每个像素字节大小 21 m_bihScreen.biCompression = BI_RGB; 22 m_bihScreen.biHeight = bmp.bmHeight;//高度 23 m_bihScreen.biPlanes = 1; 24 m_bihScreen.biSize = sizeof(BITMAPINFOHEADER); 25 m_bihScreen.biSizeImage = bmp.bmWidthBytes * bmp.bmHeight;//图像数据大小 26 m_bihScreen.biWidth = bmp.bmWidth;//宽度 27 28 byte *m_pbmScreenData = new byte[bmp.bmWidthBytes * bmp.bmHeight]; 29 GetDIBits(hMemDc,hMemBmp, 0, height, m_pbmScreenData, 30 (LPBITMAPINFO) &m_bihScreen, DIB_RGB_COLORS);//获取位图数据 从BITMAP到内存数据 31 32 TwoDimesionArray<RGBQUAD> colors(width,height); 33 for (int j=0;j<height;++j) 34 { 35 for (int i=0;i<width;++i) 36 { 37 byte *p=m_pbmScreenData+(height-1-j)*bmp.bmWidthBytes+i*4; 38 RGBQUAD c={int(*p),int(*(p+1)),int(*(p+2))}; //这里获取每个位置上的像素 39 colors.SetValue(i,j,c); 40 } 41 } 42 43 ImageIO writer; 44 writer.WriteBmp(colors,"D:\\z.bmp"); 45 }
1 void Test_captureScreenMFC() 2 { 3 CDC *pDesktopDC = CDC::FromHandle(::GetDC(NULL));//获取当前整个屏幕DC 4 int width = pDesktopDC->GetDeviceCaps(HORZRES); 5 int height = pDesktopDC->GetDeviceCaps(VERTRES); 6 7 CBitmap memBmp; 8 CDC memDC; 9 memBmp.CreateCompatibleBitmap(pDesktopDC, width, height); 10 memDC.CreateCompatibleDC(pDesktopDC); 11 memDC.SelectObject(&memBmp); //将memBitmap选入内存DC 12 13 memDC.BitBlt(0, 0, width, height, pDesktopDC, 0, 0, SRCCOPY);//复制屏幕图像到内存DC 14 15 BITMAP bmp; 16 memBmp.GetBitmap(&bmp); //CBitmap到BITMAP 17 18 BITMAPINFOHEADER m_bihScreen; 19 ZeroMemory(&m_bihScreen, sizeof(BITMAPINFOHEADER));//位图信息头 20 m_bihScreen.biBitCount = bmp.bmBitsPixel;//每个像素字节大小 21 m_bihScreen.biCompression = BI_RGB; 22 m_bihScreen.biHeight = bmp.bmHeight;//高度 23 m_bihScreen.biPlanes = 1; 24 m_bihScreen.biSize = sizeof(BITMAPINFOHEADER); 25 m_bihScreen.biSizeImage = bmp.bmWidthBytes * bmp.bmHeight;//图像数据大小 26 m_bihScreen.biWidth = bmp.bmWidth;//宽度 27 28 byte *m_pbmScreenData = new byte[bmp.bmWidthBytes * bmp.bmHeight]; 29 GetDIBits(/*pDesktopDC->m_hDC*/memDC.m_hDC, (HBITMAP)memBmp.m_hObject, 0, height, m_pbmScreenData, 30 (LPBITMAPINFO) &m_bihScreen, DIB_RGB_COLORS);//获取位图数据 从BITMAP到内存数据 31 32 TwoDimesionArray<RGBQUAD> colors(width,height); 33 for (int j=0;j<height;++j) 34 { 35 for (int i=0;i<width;++i) 36 { 37 byte *p=m_pbmScreenData+(height-1-j)*bmp.bmWidthBytes+i*4; 38 RGBQUAD c={int(*p),int(*(p+1)),int(*(p+2))}; 39 colors.SetValue(i,j,c); 40 } 41 } 42 43 ImageIO writer; 44 writer.WriteBmp(colors,"D:\\z.bmp"); 45 }
GetDIBits是DDB转化为DIB的关键函数。
TwoDimesionArray<T>是自定义的模板类，封装了二维数组的相关操作。
ImageIO 是保存图片到文件的类。
通过这两段代码显示了win32和MFC对应数据类型的不同