关于字幕叠加（远程控制），如何实现？[c#][海康]

       [StructLayout(LayoutKind.Sequential, Pack = 1, CharSet = CharSet.Ansi)]

        public struct NET_DVR_SHOWSTRINGINFO

        {

            //编码端字符叠加配置结构 

            public ushort dwShowString;

            public int wStringSize;

            public ushort wShowStringTopLeftX;

            public ushort wShowStringTopLeftY;

            //[MarshalAs(UnmanagedType.LPArray, SizeConst = 44)]

            //public char[] sString;



            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 44)]

            public string sString;



        }





        [StructLayout(LayoutKind.Sequential)]

        public struct NET_DVR_SHOWSTRING

        {

            //叠加字符结构

            public int dwSize;

            public NET_DVR_SHOWSTRINGINFO struStringInfo;

        }





        //编码端叠加字符

        [DllImport("HCNetSDK.dll")]

        public static extern bool NET_DVR_SetDVRConfig(int lUserID, int dwCommand, int lChannel, NET_DVR_SHOWSTRING lpInBuffer, int dwInBufferSize);





        private void button5_Click(object sender, EventArgs e)

        {

            NET_DVR_SHOWSTRINGINFO _showstringinfo = new NET_DVR_SHOWSTRINGINFO();



            NET_DVR_SHOWSTRING _showstring = new NET_DVR_SHOWSTRING();



            string strTT = "我是来测试的!";



            _showstring.dwSize = 1;

            _showstring.struStringInfo = _showstringinfo;

            _showstring.struStringInfo.dwShowString = 1;

            _showstring.struStringInfo.sString = strTT;

            _showstring.struStringInfo.wStringSize = strTT.Length;

            _showstring.struStringInfo.wShowStringTopLeftX = 100;

            _showstring.struStringInfo.wShowStringTopLeftY = 100;



            int iSize= Marshal.SizeOf(_showstring);



            bool bac = NET_DVR_SetDVRConfig(iLoginRef, 131, 0, _showstring, iSize);

            if (bac == false)

            {

                MessageBox.Show("失败");

            }

         }

/*****************************DS-6001D/F(end)***************************/



//单字符参数(子结构)

typedef struct 

{

	WORD wShowString;				// 预览的图象上是否显示字符,0-不显示,1-显示 区域大小704*576,单个字符的大小为32*32

	WORD wStringSize;				/* 该行字符的长度，不能大于44个字符 */

	WORD wShowStringTopLeftX;		/* 字符显示位置的x坐标 */

	WORD wShowStringTopLeftY;		/* 字符名称显示位置的y坐标 */

	char sString[44];				/* 要显示的字符内容 */

}NET_DVR_SHOWSTRINGINFO, *LPNET_DVR_SHOWSTRINGINFO;



//叠加字符(9000扩展)

typedef struct 

{

	DWORD dwSize;

	NET_DVR_SHOWSTRINGINFO struStringInfo[MAX_STRINGNUM_V30];				/* 要显示的字符内容 */

}NET_DVR_SHOWSTRING_V30, *LPNET_DVR_SHOWSTRING_V30;



//叠加字符扩展(8条字符)

typedef struct 

{

	DWORD dwSize;

	NET_DVR_SHOWSTRINGINFO struStringInfo[MAX_STRINGNUM_EX];				/* 要显示的字符内容 */

}NET_DVR_SHOWSTRING_EX, *LPNET_DVR_SHOWSTRING_EX;



//叠加字符

typedef struct 

{

	DWORD dwSize;

	NET_DVR_SHOWSTRINGINFO struStringInfo[MAX_STRINGNUM];				/* 要显示的字符内容 */

}NET_DVR_SHOWSTRING, *LPNET_DVR_SHOWSTRING;



/*********************************************************

  Function:	OnBnClickedBtnStringOk

  Desc:		finish text overlay settings

  Input:	

  Output:	

  Return:	

**********************************************************/

void CDlgRemoteShowString::OnBnClickedBtnStringOk()

{

	UpdateData(TRUE);

	char szLan[128] = {0};

	int i = m_comboShowArea.GetCurSel();

	m_struShowString.struStringInfo[i].wShowString = (WORD)m_bChkShow;

	memcpy(m_struShowString.struStringInfo[i].sString, m_csString, 44);

	m_struShowString.struStringInfo[i].wStringSize = (WORD)strlen(m_csString);

	m_struShowString.struStringInfo[i].wShowStringTopLeftX = (WORD)m_iStringX;

	m_struShowString.struStringInfo[i].wShowStringTopLeftY = (WORD)m_iStringY;	

	if (!NET_DVR_SetDVRConfig(m_lLoginID, NET_DVR_SET_SHOWSTRING_V30, m_iChanShowNum, &m_struShowString, sizeof(NET_DVR_SHOWSTRING_V30)))

	{

		g_pMainDlg->AddLog(g_pMainDlg->m_iCurDeviceIndex, OPERATION_FAIL_T, "NET_DVR_SET_SHOWSTRING_V30");

		g_StringLanType(szLan, "设置字符参数失败", "Failure to set character parameters");

		AfxMessageBox(szLan);

		return ;

	}

	g_pMainDlg->AddLog(g_pMainDlg->m_iCurDeviceIndex, OPERATION_SUCC_T, "NET_DVR_SET_SHOWSTRING_V30");

}