BitBltPicture局域网截屏图片全黑

ChbaiMou 2015-06-29 05:24:58

用的是C语言的windows服务程序做的一个局域网截屏，并发送图片的程序，结果保存的图片一片黑。
部分截屏代码：



class Intercept  

{

public:  



	//初始化 传入窗口句柄  

	Intercept(HWND hwnd1,LPCTSTR path):m_hSrcWnd(hwnd1),filepath(path)

	{



	}  

	//根据句柄获得窗口DC  

	HDC GetWindowsDC(HWND hwnd)  

	{

		return ::GetDC(hwnd);  

	}  



	//获得源窗口的宽  

	void GetWindowsWidth()  

	{  

		::RECT rect;  

		GetWindowRect(m_hSrcWnd,&rect);  

		m_nCxWnd = rect.right - rect.left;  



	}  



	//获得源窗口的高  

	void  GetWindowHeigh()  

	{  

		::RECT rect;  

		::GetWindowRect(m_hSrcWnd,&rect);  

		m_nCyWnd = rect.bottom - rect.top;  

	}  



	//将源窗口画到目标窗口  

	BOOL BitBltPicture()  

	{

		CString m_str(filepath);m_str+=FileName;filepath = (LPCTSTR)m_str;

		m_hScrDC  = GetWindowsDC(GetDesktopWindow()/*m_hSrcWnd*/);

		GetWindowsWidth();  

		GetWindowHeigh();

		//c创建位图

		if(!img.Create(m_nCxWnd,m_nCyWnd,32))

			return -1;

		m_hdcMem = ::CreateCompatibleDC(m_hScrDC);  

		m_hBitmap   = ::CreateCompatibleBitmap(m_hScrDC,m_nCxWnd,m_nCyWnd);   

		::SelectObject(m_hdcMem,m_hBitmap);  

		::BitBlt(m_hdcMem,0,0,m_nCxWnd,m_nCyWnd,m_hScrDC,0,0,SRCCOPY);  

		::BitBlt(img.GetDC(),0,0,m_nCxWnd,m_nCyWnd,m_hdcMem,0,0,SRCCOPY);

		img.Save(filepath,Gdiplus::ImageFormatJPEG);

		img.ReleaseDC();

		

		return 0;

	}  



	~Intercept()  

	{  

		::DeleteDC(m_hdcMem);  

		::DeleteDC(m_hScrDC);  

		//::DeleteDC(m_hDestDC);  

		::DeleteObject(m_hBitmap);	

		::ReleaseDC(m_hSrcWnd,m_hScrDC);	

	}

private:  

	HWND        m_hSrcWnd;  

	//HWND        m_hDestWnd;  

	int         m_nCxWnd;  

	int         m_nCyWnd;  

	HDC         m_hdcMem;  

	HDC         m_hScrDC;  

	//HDC         m_hDestDC;  

	HBITMAP     m_hBitmap;

	LPCTSTR		filepath;

	CImage		img;

};

保存图片代码：每3秒保存一张图片



void CSampleService::ServiceWorkerThread(void)

{

	CString mstr(MAPPATH);

	DWORD jpgno = 0;

	mstr += FileName;

	Intercept * bitmap;

    // Periodically check if the service is stopping.

	WaitForSingleObject(m_StartThreadEvent,INFINITE);

    while (1)

    {

		Sleep(3000);

		if (m_fPausing)

		{

			Sleep(100);

			continue;

		}

		bitmap = new Intercept(::GetDesktopWindow(),MAPPATH);

		if((m_fStopping))

		{

			break;

		}

        // Perform main service function here...

		if(bitmap->BitBltPicture() != 0){

			 WriteErrorLogEntry(L"SaveScreenJpg",144);

			 continue;

		}

		delete bitmap;

		if (!sendmap((LPCTSTR)mstr,serverIp,serverPort))

		{

			WriteErrorLogEntry(L"SendJpgToServerFeil",4);

			continue;

		}

		

	}

        //::Sleep(2000);  // Simulate some lengthy operations.

    // Signal the stopped event.

    SetEvent(m_hStoppedEvent);

}