public

Inheritance Graph

graph BT
	EventQueue
	click EventQueue "classUtil_1_1UI_1_1EventQueue"

Description

Data structure for event handling.

The event queue manages input events that are created by different generators and consumed by different handlers.

The event generators can be the windowing system or a library that supports game controllers, for example. The different generators can register themselves as event generator using registerEventGenerator() .

Multiple event handlers can be registered using registerEventHandler() . Optionally, a filter function can be given that ensures that only specific events are given to the handler.

During process() , first the event generators are asked for new events. After that, all existing events are filtered and given to the respective event handlers.

Note: This class has to be used from the same thread as the window. For the reasons, seehttp://www.libsdl.org/docs/html/sdlpumpevents.htmlor Section 2.7 ofhttp://www.x.org/docs/X11/xlib.pdf.

Author: Benjamin Eikel

Date: 2012-09-12

Public Types

   
   
typedef std::function< std::deque< Event >)> event_generator_t
   
typedef std::function< bool(const Event &)> event_handler_t

Public Functions

   
   
std::size_t getNumEventsAvailable() const
   
void pushEvent(const Event & newEvent)
   
const Event & peekEvent() const
   
Event popEvent()
   
void registerEventGenerator(const event_generator_t & generator)
   
void registerEventHandler(const event_handler_t & handler)
   
void process()

Documentation

typedef
Util::UI::EventQueue::event_generator_t

public
 
 
typedef std::function< std::deque< Event >)> event_generator_t

Function type for an event generator that returns an array of events.

Defined in Util/UI/EventQueue.h:49

typedef
Util::UI::EventQueue::event_handler_t

public
 
 
typedef std::function< bool(const Event &)> event_handler_t

Function type for an event handler that receives a single event. The return type indicates if the event has been handled: If the handler returnstrue, it has handled the event. If the event has not been handled (return valuefalse), it will be passed to the next handler.

Defined in Util/UI/EventQueue.h:58

function
Util::UI::EventQueue::getNumEventsAvailable

public const
   
   
std::size_t getNumEventsAvailable( ) const

Return the number of unprocessed events that are waiting in the event queue.

Returns

Number of events waiting for processing

Defined in Util/UI/EventQueue.h:86

function
Util::UI::EventQueue::pushEvent

public
     
     
void pushEvent( const Event & newEvent )

Add a new event to the event queue.

Parameters

newEvent
Event that will be inserted

Defined in Util/UI/EventQueue.h:93

function
Util::UI::EventQueue::peekEvent

public const
   
   
const Event & peekEvent( ) const

Read the first element from the event queue without removing it.

Returns

Read-only reference to the first event

Exceptions

std::logic_error
if there are no events available

Defined in Util/UI/EventQueue.h:101

function
Util::UI::EventQueue::popEvent

public
   
   
Event popEvent( )

Remove the first element from the event queue and return it.

Returns

Element that has been the first element of the event queue

Exceptions

std::logic_error
if there are no events available

Defined in Util/UI/EventQueue.h:109

function
Util::UI::EventQueue::registerEventGenerator

public
     
     
void registerEventGenerator( const event_generator_t & generator )

Register the given function as an event generator.

Parameters

generator
Event generator that creates an array of events

Defined in Util/UI/EventQueue.h:116

function
Util::UI::EventQueue::registerEventHandler

public
     
     
void registerEventHandler( const event_handler_t & handler )

Register the given function as an event handler.

Parameters

handler
Event handler that takes a single event

Defined in Util/UI/EventQueue.h:123

function
Util::UI::EventQueue::process

public
   
   
void process( )

Collect generated events and pass them to handlers.

Note: This function has to be called regularly to ensure the processing of events.

Defined in Util/UI/EventQueue.h:133