gg::IObservable Class Reference

Every IVideoSource that broadcasts video frames needs to implement this interface, which defines the observable (subject / publisher) part of the observer design pattern (aka subscriber-publisher). More...

#include <iobservable.h>

Inheritance diagram for gg::IObservable:

Public Member Functions
virtual	~IObservable ()
virtual void	attach (IObserver &observer)
	Attach given observer to this observable. If observer already attached, no action is taken, no action is taken. More...
virtual void	detach (IObserver &observer)
	Detach given observer from this observable. More...
virtual void	notify (VideoFrame &frame) noexcept
	Notify all attached observers of new data. More...

Protected Member Functions
bool	attached (const IObserver &observer) const noexcept
	Check whether passed observer is already attached. Because this function is protected, no thread-safety operation is performed inside it. More...

Protected Attributes
std::vector< IObserver *>	_observers
std::mutex	_observers_lock

Detailed Description

Every IVideoSource that broadcasts video frames needs to implement this interface, which defines the observable (subject / publisher) part of the observer design pattern (aka subscriber-publisher).

Attention

In Python: an intermediate node in a video processing pipeline should extend the IObservableObserver class (not available in C++) instead of IObservable and IObserver. Below is the source code for a sample processing node in Python.

from pygiftgrab import IObservableObserver

class MyProcNode(IObservableObserver):

    def __init__(self):
        super(MyProcNode, self).__init__()

    def update(self, frame):
        # Implement gg::IObserver::update(frame)
        pass

Note that no new buffer is created when broadcasting data, i.e. every IObserver is responsible for ensuring data is promptly copied to their own data buffer.

Constructor & Destructor Documentation

~IObservable()

gg::IObservable::~IObservable ( )

virtual

Member Function Documentation

attach()

void gg::IObservable::attach ( IObserver &  observer )

virtual

Attach given observer to this observable. If observer already attached, no action is taken, no action is taken.

Parameters

observer

Exceptions

ObserverError

with a detailed message if attach attempt unsuccessful

attached()

bool gg::IObservable::attached ( const IObserver &  observer ) const

protectednoexcept

Check whether passed observer is already attached. Because this function is protected, no thread-safety operation is performed inside it.

Parameters

observer

Returns

See also

_observers_lock

detach()

void gg::IObservable::detach ( IObserver &  observer )

virtual

Detach given observer from this observable.

Parameters

observer

Exceptions

ObserverError

with a detailed message if detach attempt unsuccessful

notify()

void gg::IObservable::notify ( VideoFrame &  frame )

virtualnoexcept

Notify all attached observers of new data.

Attention

In Python: This function is not available yet.

Parameters

frame

Member Data Documentation

_observers

std::vector< IObserver * > gg::IObservable::_observers

protected

_observers_lock

std::mutex gg::IObservable::_observers_lock

protected

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The documentation for this class was generated from the following files:

• src/api/iobservable.h
• src/api/iobservable.cpp