Adding Callback Functions to an Application

An application can register callback functions with the capture window so that it notifies the application in the following circumstances:

• The status changes

• Errors occur

• Video frame and audio buffers become available

• The application should yield during streaming capture

The following example creates a capture window and registers status, error, video stream, and frame callback functions in the message-processing loop of an application. It also includes a sample statement for disabling a callback function. Subsequent examples show simple status, error, and frame callback functions.

case WM_CREATE:

{

char achDeviceName[80] ;

char achDeviceVersion[100] ;

char achBuffer[100] ;

WORD wDriverCount = 0 ;

WORD wIndex ;

WORD wError ;

HMENU hMenu ;

// Create a capture window using the capCreateCaptureWindow macro.

ghWndCap = capCreateCaptureWindow((LPSTR)"Capture Window",

WS_CHILD | WS_VISIBLE, 0, 0, 160, 120, (HWND) hWnd, (int) 0);

// Register the error callback function using the

// capSetCallbackOnError macro.

capSetCallbackOnError(ghWndCap, fpErrorCallback);

// Register the status callback function using the

// capSetCallbackOnStatus macro.

capSetCallbackOnStatus(ghWndCap, fpStatusCallback);

// Register the video-stream callback function using the

// capSetCallbackOnVideoStream macro.

capSetCallbackOnVideoStream(ghWndCap, fpVideoCallback);

// Register the frame callback function using the

// capSetCallbackOnFrame macro.

capSetCallbackOnFrame(ghWndCap, fpFrameCallback);

// Connect to a capture driver

break;

}

case WM_CLOSE:

{

// Use the capSetCallbackOnFrame macro to

// disable the frame callback. Similar calls exist for the other

// callback functions.

capSetCallbackOnFrame(hWndC, NULL);

break;

}

Software for developers

Delphi Components
.Net Components
Software for Android Developers

More information resources

MegaDetailed.Net
Unix Manual Pages
Delphi Examples