.. module:: pygame.event :synopsis: pygame module for interacting with events and queues
Pygame handles all its event messaging through an event queue. The routines in this module help you manage that event queue. The input queue is heavily dependent on the :mod:`pygame.display` module. If the display has not been initialized and a video mode not set, the event queue may not work properly. The event subsystem should be called from the main thread. If you want to post events into the queue from other threads, please use the :mod:`pygame.fastevent` module.
The event queue has an upper limit on the number of events it can hold
(128 for standard SDL 1.2). When the queue becomes full new events are quietly
dropped. To prevent lost events, especially input events which signal a quit
command, your program must handle events every frame (with
pygame.event.get(), pygame.event.pump(), pygame.event.wait(),
pygame.event.peek() or pygame.event.clear())
and process them. Not handling events may cause your system to decide your
program has locked up. To speed up queue processing use
:func:`pygame.event.set_blocked()` to limit which events get queued.
To get the state of various input devices, you can forego the event queue and access the input devices directly with their appropriate modules: :mod:`pygame.mouse`, :mod:`pygame.key`, and :mod:`pygame.joystick`. If you use this method, remember that pygame requires some form of communication with the system window manager and other parts of the platform. To keep pygame in sync with the system, you will need to call :func:`pygame.event.pump()` to keep everything current. Usually, this should be called once per game loop. Note: Joysticks will not send any events until the device has been initialized.
The event queue contains :class:`pygame.event.EventType` event objects. There are a variety of ways to access the queued events, from simply checking for the existence of events, to grabbing them directly off the stack. The event queue also offers some simple filtering which can slightly help performance by blocking certain event types from the queue. Use :func:`pygame.event.set_allowed()` and :func:`pygame.event.set_blocked()` to change this filtering. By default, all event types can be placed on the queue.
All :class:`pygame.event.EventType` instances contain an event type identifier and attributes specific to that event type. The event type identifier is accessible as the :attr:`pygame.event.EventType.type` property. Any of the event specific attributes can be accessed through the :attr:`pygame.event.EventType.__dict__` attribute or directly as an attribute of the event object (as member lookups are passed through to the object's dictionary values). The event object has no method functions. Users can create their own new events with the :func:`pygame.event.Event()` function.
The event type identifier is in between the values of NOEVENT and
NUMEVENTS. User defined events should have a value in the inclusive range
of USEREVENT to NUMEVENTS - 1. It is recommended all user events follow
this system.
Events support equality and inequality comparisons. Two events are equal if they are the same type and have identical attribute values.
While debugging and experimenting, you can print an event object for a quick display of its type and members. The function :func:`pygame.event.event_name()` can be used to get a string representing the name of the event type.
Events that come from the system will have a guaranteed set of member attributes based on the type. The following is a list event types with their specific attributes.
QUIT none ACTIVEEVENT gain, state KEYDOWN key, mod, unicode, scancode KEYUP key, mod MOUSEMOTION pos, rel, buttons MOUSEBUTTONUP pos, button MOUSEBUTTONDOWN pos, button JOYAXISMOTION joy (deprecated), instance_id, axis, value JOYBALLMOTION joy (deprecated), instance_id, ball, rel JOYHATMOTION joy (deprecated), instance_id, hat, value JOYBUTTONUP joy (deprecated), instance_id, button JOYBUTTONDOWN joy (deprecated), instance_id, button VIDEORESIZE size, w, h VIDEOEXPOSE none USEREVENT code
You can also find a list of constants for keyboard keys :ref:`here <key-constants-label>`.
.. versionadded:: 1.9.2
On MacOSX when a file is opened using a pygame application, a USEREVENT
with its code attribute set to pygame.USEREVENT_DROPFILE is generated.
There is an additional attribute called filename where the name of the file
being accessed is stored.
USEREVENT code=pygame.USEREVENT_DROPFILE, filename
.. versionadded:: 1.9.5
When compiled with SDL2, pygame has these additional events and their attributes.
AUDIODEVICEADDED which, iscapture AUDIODEVICEREMOVED which, iscapture FINGERMOTION touch_id, finger_id, x, y, dx, dy FINGERDOWN touch_id, finger_id, x, y, dx, dy FINGERUP touch_id, finger_id, x, y, dx, dy MULTIGESTURE touch_id, x, y, pinched, rotated, num_fingers TEXTEDITING text, start, length TEXTINPUT text
.. versionadded:: 2.0.0
pygame can recognize text or files dropped in its window. If a file
is dropped, file will be its path. The DROPTEXT event is only supported
on X11.
DROPBEGIN DROPCOMPLETE DROPFILE file DROPTEXT text
.. versionadded:: 2.0.0
Events reserved for :mod:`pygame.midi` use.
MIDIIN MIDIOUT
.. versionadded:: 2.0.0
SDL2 supports controller hotplugging:
CONTROLLERDEVICEADDED device_index JOYDEVICEADDED device_index CONTROLLERDEVICEREMOVED instance_id JOYDEVICEREMOVED instance_id CONTROLLERDEVICEREMAPPED instance_id
Also in this version, instance_id attributes were added to joystick events,
and the joy attribute was deprecated.
.. function:: pump
| :sl:`internally process pygame event handlers`
| :sg:`pump() -> None`
For each frame of your game, you will need to make some sort of call to the
event queue. This ensures your program can internally interact with the rest
of the operating system. If you are not using other event functions in your
game, you should call ``pygame.event.pump()`` to allow pygame to handle
internal actions.
This function is not necessary if your program is consistently processing
events on the queue through the other :mod:`pygame.event` functions.
There are important things that must be dealt with internally in the event
queue. The main window may need to be repainted or respond to the system. If
you fail to make a call to the event queue for too long, the system may
decide your program has locked up.
.. caution::
This function should only be called in the thread that initialized :mod:`pygame.display`.
.. ## pygame.event.pump ##
.. function:: get | :sl:`get events from the queue` | :sg:`get(eventtype=None) -> Eventlist` | :sg:`get(eventtype=None, pump=True) -> Eventlist` This will get all the messages and remove them from the queue. If a type or sequence of types is given only those messages will be removed from the queue. If you are only taking specific events from the queue, be aware that the queue could eventually fill up with the events you are not interested. If ``pump`` is ``True`` (the default), then :func:`pygame.event.pump()` will be called. .. versionadded:: 1.9.5 ``pump`` .. ## pygame.event.get ##
.. function:: poll
| :sl:`get a single event from the queue`
| :sg:`poll() -> EventType instance`
Returns a single event from the queue. If the event queue is empty an event
of type ``pygame.NOEVENT`` will be returned immediately. The returned event
is removed from the queue.
.. caution::
This function should only be called in the thread that initialized :mod:`pygame.display`.
.. ## pygame.event.poll ##
.. function:: wait
| :sl:`wait for a single event from the queue`
| :sg:`wait() -> EventType instance`
Returns a single event from the queue. If the queue is empty this function
will wait until one is created. The event is removed from the queue once it
has been returned. While the program is waiting it will sleep in an idle
state. This is important for programs that want to share the system with
other applications.
.. caution::
This function should only be called in the thread that initialized :mod:`pygame.display`.
.. ## pygame.event.wait ##
.. function:: peek | :sl:`test if event types are waiting on the queue` | :sg:`peek(eventtype=None) -> bool` | :sg:`peek(eventtype=None, pump=True) -> bool` Returns ``True`` if there are any events of the given type waiting on the queue. If a sequence of event types is passed, this will return ``True`` if any of those events are on the queue. If ``pump`` is ``True`` (the default), then :func:`pygame.event.pump()` will be called. .. versionadded:: 1.9.5 ``pump`` .. ## pygame.event.peek ##
.. function:: clear | :sl:`remove all events from the queue` | :sg:`clear(eventtype=None) -> None` | :sg:`clear(eventtype=None, pump=True) -> None` Removes all events from the queue. If ``eventtype`` is given, removes the given event or sequence of events. This has the same effect as :func:`pygame.event.get()` except ``None`` is returned. It can be slightly more efficient when clearing a full event queue. If ``pump`` is ``True`` (the default), then :func:`pygame.event.pump()` will be called. .. versionadded:: 1.9.5 ``pump`` .. ## pygame.event.clear ##
.. function:: event_name | :sl:`get the string name from an event id` | :sg:`event_name(type) -> string` Returns a string representing the name (in CapWords style) of the given event type. "UserEvent" is returned for all values in the user event id range. "Unknown" is returned when the event type does not exist. .. ## pygame.event.event_name ##
.. function:: set_blocked | :sl:`control which events are allowed on the queue` | :sg:`set_blocked(type) -> None` | :sg:`set_blocked(typelist) -> None` | :sg:`set_blocked(None) -> None` The given event types are not allowed to appear on the event queue. By default all events can be placed on the queue. It is safe to disable an event type multiple times. If ``None`` is passed as the argument, ALL of the event types are blocked from being placed on the queue. .. ## pygame.event.set_blocked ##
.. function:: set_allowed | :sl:`control which events are allowed on the queue` | :sg:`set_allowed(type) -> None` | :sg:`set_allowed(typelist) -> None` | :sg:`set_allowed(None) -> None` The given event types are allowed to appear on the event queue. By default, all event types can be placed on the queue. It is safe to enable an event type multiple times. If ``None`` is passed as the argument, ALL of the event types are allowed to be placed on the queue. .. ## pygame.event.set_allowed ##
.. function:: get_blocked | :sl:`test if a type of event is blocked from the queue` | :sg:`get_blocked(type) -> bool` | :sg:`get_blocked(typelist) -> bool` Returns ``True`` if the given event type is blocked from the queue. If a sequence of event types is passed, this will return ``True`` if any of those event types are blocked. .. ## pygame.event.get_blocked ##
.. function:: set_grab | :sl:`control the sharing of input devices with other applications` | :sg:`set_grab(bool) -> None` When your program runs in a windowed environment, it will share the mouse and keyboard devices with other applications that have focus. If your program sets the event grab to ``True``, it will lock all input into your program. It is best to not always grab the input, since it prevents the user from doing other things on their system. .. ## pygame.event.set_grab ##
.. function:: get_grab | :sl:`test if the program is sharing input devices` | :sg:`get_grab() -> bool` Returns ``True`` when the input events are grabbed for this application. .. ## pygame.event.get_grab ##
.. function:: post | :sl:`place a new event on the queue` | :sg:`post(Event) -> None` Places the given event at the end of the event queue. This is usually used for placing ``pygame.USEREVENT`` events on the queue. Although any type of event can be placed, if using the system event types your program should be sure to create the standard attributes with appropriate values. If the event queue is full a :exc:`pygame.error` is raised. Caution: In pygame 2.0, calling this function with event types defined by pygame (such as ``pygame.KEYDOWN``) may put events into the SDL2 event queue. In this case, an error may be raised if standard attributes of that event are missing or have incompatible values, and unexpected properties may be silently omitted. In order to avoid this behaviour, custom event properties should be used with custom event types. This behaviour is not guaranteed. .. ## pygame.event.post ##
.. function:: custom_type | :sl:`make custom user event type` | :sg:`custom_type() -> int` Reserves a ``pygame.USEREVENT`` for a custom use. If too many events are made a :exc:`pygame.error` is raised. .. versionadded:: 2.0.0.dev3 .. ## pygame.event.custom_type ##
.. function:: Event | :sl:`create a new event object` | :sg:`Event(type, dict) -> EventType instance` | :sg:`Event(type, \**attributes) -> EventType instance` Creates a new event with the given type and attributes. The attributes can come from a dictionary argument with string keys or from keyword arguments. .. ## pygame.event.Event ##
A pygame object that represents an event. User event instances are created
with an :func:`pygame.event.Event()` function call. The EventType type
is not directly callable. EventType instances support attribute
assignment and deletion.
.. attribute:: type | :sl:`event type identifier.` | :sg:`type -> int` Read-only. The event type identifier. For user created event objects, this is the ``type`` argument passed to :func:`pygame.event.Event()`. For example, some predefined event identifiers are ``QUIT`` and ``MOUSEMOTION``. .. ## pygame.event.EventType.type ##
.. attribute:: __dict__ | :sl:`event attribute dictionary` | :sg:`__dict__ -> dict` Read-only. The event type specific attributes of an event. The ``dict`` attribute is a synonym for backward compatibility. For example, the attributes of a ``KEYDOWN`` event would be ``unicode``, ``key``, and ``mod`` .. ## pygame.event.EventType.__dict__ ##
.. versionadded:: 1.9.2 Mutable attributes.