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OnFrameOverlayUsingDC

event

Deprecated

Kept for backward compatibility only.

Delphi
property OnFrameOverlayUsingDC: TOnFrameOverlayUsingDC read FOnFrameOverlayUsingDC write FOnFrameOverlayUsingDC;
C++Builder
__property TOnFrameOverlayUsingDC OnFrameOverlayUsingDC = {read=FOnFrameOverlayUsingDC, write=FOnFrameOverlayUsingDC};
typedef void __fastcall (__closure *TOnFrameOverlayUsingDC)(System::TObject* Sender, HDC Dc, System::LongWord FrameNumber, LargeInteger FrameTime, System::LongInt FrameId);
C#
public event OnFrameOverlayUsingDCEventHandler OnFrameOverlayUsingDC;
public delegate void OnFrameOverlayUsingDCEventHandler(object sender, TOnFrameOverlayUsingDCEventArgs e);
VB.NET
Public Event OnFrameOverlayUsingDC As OnFrameOverlayUsingDCEventHandler
Public Delegate Sub OnFrameOverlayUsingDCEventHandler(sender As Object, e As TOnFrameOverlayUsingDCEventArgs)
C++/Qt
void SetOnFrameOverlayUsingDC (TOnFrameOverlayUsingDCCb OnFrameOverlayUsingDCCb);
typedef void CALLBACK TOnFrameOverlayUsingDCCb (void *Object, void *Sender, HDC Dc, unsigned int FrameNumber, __int64 FrameTime, int FrameId);

Put the application code in this event to draw graphic objects over video frames by using the frame DC.

Remarks

DEPRECATED, use OnFrameBitmap instead. This TOnFrameOverlayUsingDC event is used to draw graphic objects over video frames, by using the frame device context.

This event occurs for each video frame that goes through the video stream, during preview, recording or playback.

The frame grabber must be enabled for this event to occur.

From this event it is possible to:

  • draw a bitmap over frames by calling DrawBitmapOverFrame,

  • draw anything using the Dc parameter (device context) and GDI functions.

This event is TIME CRITICAL. The code used in this event must be as short and fast as possible.

Sample code is included in the MainDemo project.

To get information about the current video frame, invoke GetFrameInfo (FrameId,...). E.g.

SampleTimeHour = VideoGrabber.GetFrameInfo (FrameId, fi_SampleTime_Hour)

Not raised for the frames kept in NV12: 4K / 8K video played with FrameGrabberRGBFormat = fgf_Default (default setting), or FrameGrabberRGBFormat = fgf_NV12 (a warning is reported by OnLog when it is assigned before opening the video). Set FrameGrabberRGBFormat = fgf_RGB32 before opening the video to receive it for every video.