窗口截图(二)

窗口截图，可以获取遮挡窗口完整的图像，并保存到bmp文件中去。主要用到的函数中PrintWindow，VC6不支持该函数，请使用VS2008来编译。其它需求如平台要求请参考MSDN文档。

void SaveHwndToBmpFile(HWND hWnd, LPCTSTR lpszPath) 
{
     HDC hDC = ::GetWindowDC(hWnd); 
     ASSERT(hDC); 
     
     HDC hMemDC = ::CreateCompatibleDC(hDC); 
     ASSERT(hMemDC);
     
      RECT rc;
       ::GetWindowRect(hWnd, &rc); 
       
       HBITMAP hBitmap = ::CreateCompatibleBitmap(hDC, rc.right - rc.left, rc.bottom - rc.top);
       ASSERT(hBitmap);
       
       HBITMAP hOldBmp = (HBITMAP)::SelectObject(hMemDC, hBitmap); 
       
       ::PrintWindow(hWnd, hMemDC, 0); 
       
       BITMAP bitmap = {0}; 
       ::GetObject(hBitmap, sizeof(BITMAP), &bitmap); 
       
       BITMAPINFOHEADER bi = {0}; 
       BITMAPFILEHEADER bf = {0}; 
       CONST int nBitCount = 24; 
       bi.biSize = sizeof(BITMAPINFOHEADER); 
       bi.biWidth = bitmap.bmWidth; 
       bi.biHeight = bitmap.bmHeight; 
       bi.biPlanes = 1; 
       bi.biBitCount = nBitCount; 
       bi.biCompression = BI_RGB; 
       DWORD dwSize = ((bitmap.bmWidth * nBitCount + 31) / 32) * 4 * bitmap.bmHeight; 
       
       HANDLE hDib = GlobalAlloc(GHND, dwSize + sizeof(BITMAPINFOHEADER)); 
       LPBITMAPINFOHEADER lpbi = (LPBITMAPINFOHEADER)GlobalLock(hDib); 
       *lpbi = bi; 
       ::GetDIBits(hMemDC, hBitmap, 0, bitmap.bmHeight, (BYTE*)lpbi + sizeof(BITMAPINFOHEADER), (BITMAPINFO*)lpbi, DIB_RGB_COLORS); 
       
       try 
       { 
           CFile file; 
           file.Open(lpszPath, CFile::modeCreate | CFile::modeWrite); 
           bf.bfType = 0x4d42; 
           dwSize += sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER); 
           bf.bfSize = dwSize; 
           bf.bfOffBits = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER); 
           file.Write((BYTE*)&bf, sizeof(BITMAPFILEHEADER)); 
           file.Write((BYTE*)lpbi, dwSize); file.Close(); 
        } 
        catch(CFileException* e) 
        { 
            e->ReportError(); 
            e->Delete(); 
        } 
        
        GlobalUnlock(hDib); 
        GlobalFree(hDib); 
        
        ::SelectObject(hMemDC, hOldBmp); 
        ::DeleteObject(hBitmap);	
        ::DeleteObject(hMemDC); 
        ::ReleaseDC(hWnd, hDC); 
} 

// 调用方法 
HWND hWnd = ::FindWindow(NULL, _T("XXX")); 
if(hWnd) 
{
    SaveHwndToBmpFile(hWnd, _T("F://12.bmp")); 
}