简述
使用海康摄像头采集图像时，需要在图像上添加图标、文字等额外数据。可选择使用SDK提供的NET_DVR_RigisterDrawFun()函数注册绘图回调函数，使用NET_DVR_RealPlay_V40()的返回值（用于在DrawFun()函数中区分通道数据）及DrawFun回调函数的指针进行注册。注意：使用DrawFun回调函数，需要在调用NET_DVR_RealPlay_V40()时将第三个参数设置为null。
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代码
class DeviceCamera : IDeviceCamera
{
private CameraInfo m_stCameraInfo;
private bool m_bInitSDK = false;
private Int32 m_lUserID = -1;
private Int32 m_lRealHandle = -1;
private CHCNetSDK.DRAWFUN cbDrawFun = null;
public override bool InitCamera( CameraInfo stInfo )
{
m_stCameraInfo = stInfo;
//
m_bInitSDK = CHCNetSDK.NET_DVR_Init();
if ( m_bInitSDK == false )
{
uint nError = CHCNetSDK.NET_DVR_GetLastError();
MessageBox.Show( "NET_DVR_Init error! ErrorCode: " + nError );
return false;
}
else
CHCNetSDK.NET_DVR_SetLogToFile( 3, "C:\\SdkLog\\", true );
CHCNetSDK.NET_DVR_SetConnectTime( 5000, 1 );
CHCNetSDK.NET_DVR_SetReconnect( 10000, 1 );
string DVRIPAddress = stInfo.strIP;
Int16 DVRPortNumber = stInfo.nPort;
string DVRUserName = stInfo.strUserName;
string DVRPassword = stInfo.strPassword;
CHCNetSDK.NET_DVR_DEVICEINFO_V30 DeviceInfo = new CHCNetSDK.NET_DVR_DEVICEINFO_V30();
m_lUserID = CHCNetSDK.NET_DVR_Login_V30( DVRIPAddress, DVRPortNumber, DVRUserName, DVRPassword, ref DeviceInfo );
if ( m_lUserID < 0 )
{
MessageBox.Show( "登录失败！" );
CHCNetSDK.NET_DVR_Cleanup();
return false;
}
//
CHCNetSDK.NET_DVR_PREVIEWINFO lpPreviewInfo = new CHCNetSDK.NET_DVR_PREVIEWINFO()
{
dwStreamType = 0,
dwLinkMode = 0,
bBlocked = true,
dwDisplayBufNum = 10,
};
//遍历PictureBox列表
cbDrawFun = new CHCNetSDK.DRAWFUN( fDrawFun );
int nPicBoxSize = m_stCameraInfo.lstPicBoxHdc.Count() <= 4 ? m_stCameraInfo.lstPicBoxHdc.Count() : 4; //海康摄像头模拟通道数 <= 4
for ( int nPicBoxIndex = 1; nPicBoxIndex <= nPicBoxSize; nPicBoxIndex++ )
{
lpPreviewInfo.hPlayWnd = m_stCameraInfo.lstPicBoxHdc[ nPicBoxIndex - 1 ];
lpPreviewInfo.lChannel = nPicBoxIndex;
m_lRealHandle = CHCNetSDK.NET_DVR_RealPlay_V40( m_lUserID, ref lpPreviewInfo, null, new IntPtr() );
//设置异常消息回调函数
bool bRet = CHCNetSDK.NET_DVR_SetExceptionCallBack_V30( 0, lpPreviewInfo.hPlayWnd, new CHCNetSDK.EXCEPYIONCALLBACK( cbException ), new IntPtr() );
if ( !bRet )
MessageBox.Show( "设置异常消息回调函数失败！" );
//注册绘图回调函数
bRet = CHCNetSDK.NET_DVR_RigisterDrawFun( m_lRealHandle, cbDrawFun, 0 );
if ( !bRet )
{
MessageBox.Show( "注册绘图回调函数失败！" );
return false;
}
}
return true;
}
private void fDrawFun( int lRealHandle, IntPtr hDC, uint dwUser )
{
try
{
Graphics pDC = Graphics.FromHdc( hDC );
if ( null == pDC )
return;
Brush hBrush = new SolidBrush( Color.Red );
Pen pen = new Pen( hBrush );
Rectangle rectTmp = new Rectangle( 100, 100, 100, 100 );
if( 0 == lRealHandle )//Channel 1
{
//Image
Bitmap img = new Bitmap( "../Images/NucSource.png" );
pDC.DrawImage( img, rectTmp );
//Text
string strText = "Novel RPS";
Font font = new Font( "黑体", 18, FontStyle.Italic | FontStyle.Bold );
Point pt = new Point( 100, 75 );
pDC.DrawString( strText, font, hBrush, pt );
//Rectangle
pDC.DrawRectangle( pen, rectTmp );
img.Dispose();
}
else if ( 1 == lRealHandle )//Channel 2
{
//Text
string strText = "Novel RPS";
Font font = new Font( "黑体", 18, FontStyle.Italic | FontStyle.Bold );
Point pt = new Point( 100, 75 );
pDC.DrawString( strText, font, hBrush, pt );
}
else if ( 2 == lRealHandle )//Channel 3
{
//Rectangle
pDC.DrawRectangle( pen, rectTmp );
}
else if ( 3 == lRealHandle )//Channel 4
{
//Image
Bitmap img = new Bitmap( "../Images/NucSource.png" );
pDC.DrawImage( img, rectTmp );
img.Dispose();
}
hBrush.Dispose();
pen.Dispose();
pDC.Dispose();
}
catch
{
uint nError = CHCNetSDK.NET_DVR_GetLastError();
if( nError != 0 )
MessageBox.Show( "cbDrawFun -- Catch Error Code: " + nError );
}
}
private void cbException( uint dwType, int lUserID, int lHandle, IntPtr pUser )
{
switch( dwType )
{
case 0x8000:
MessageBox.Show( "语音对讲时网络异常！" );
break;
case 0x8002:
MessageBox.Show( "报警上传时网络异常！" );
break;
case 0x8003:
MessageBox.Show( "网络预览时网络异常！" );
break;
case 0x8004:
MessageBox.Show( "透明通道传输时网络异常！" );
break;
case 0x8005:
MessageBox.Show( "预览时重连！" );
break;
default:
MessageBox.Show( "摄像头默认异常！" );
break;
}
}
}
注：代码中使用PictureBox显示摄像头图像，故将其句柄设置给 lpPreviewInfo.hPlayWnd。
效果示例
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本文题目：C#：使用海康SDK绘图回调函数DrawFun()-创新互联
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