.. include:: common.txt

:mod:`pygame.joystick`
======================

.. module:: pygame.joystick
   :synopsis: Pygame module for interacting with joysticks, gamepads, and trackballs.

| :sl:`Pygame module for interacting with joysticks, gamepads, and trackballs.`

The joystick module manages the joystick devices on a computer.
Joystick devices include trackballs and video-game-style
gamepads, and the module allows the use of multiple buttons and "hats".
Computers may manage multiple joysticks at a time.

Each instance of the Joystick class represents one gaming device plugged 
into the computer. If a gaming pad has multiple joysticks on it, than the
joystick object can actually represent multiple joysticks on that single
game device.

For a quick way to initialise the joystick module and get a list of Joystick instances
use the following code::

    pygame.joystick.init()
    joysticks = [pygame.joystick.Joystick(x) for x in range(pygame.joystick.get_count())]

The following event types will be generated by the joysticks ::

    JOYAXISMOTION JOYBALLMOTION JOYBUTTONDOWN JOYBUTTONUP JOYHATMOTION

The event queue needs to be pumped frequently for some of the methods to work.
So call one of pygame.event.get, pygame.event.wait, or pygame.event.pump regularly.


.. function:: init

   | :sl:`Initialize the joystick module.`
   | :sg:`init() -> None`

   This function is called automatically by ``pygame.init()``.

   It initializes the joystick module. This will scan the system for all
   joystick devices. The module must be initialized before any other functions
   will work.

   It is safe to call this function more than once.

   .. ## pygame.joystick.init ##

.. function:: quit

   | :sl:`Uninitialize the joystick module.`
   | :sg:`quit() -> None`

   Uninitialize the joystick module. After you call this any existing joystick
   objects will no longer work.

   It is safe to call this function more than once.

   .. ## pygame.joystick.quit ##

.. function:: get_init

   | :sl:`Returns True if the joystick module is initialized.`
   | :sg:`get_init() -> bool`

   Test if the ``pygame.joystick.init()`` function has been called.

   .. ## pygame.joystick.get_init ##

.. function:: get_count

   | :sl:`Returns the number of joysticks.`
   | :sg:`get_count() -> count`

   Return the number of joystick devices on the system. The count will be 0 if
   there are no joysticks on the system.

   When you create Joystick objects using ``Joystick(id)``, you pass an integer
   that must be lower than this count.

   .. ## pygame.joystick.get_count ##

.. class:: Joystick

   | :sl:`Create a new Joystick object.`
   | :sg:`Joystick(id) -> Joystick`

   Create a new joystick to access a physical device. The id argument must be a
   value from 0 to pygame.joystick.get_count()-1.

   To access most of the Joystick methods, you'll need to ``init()`` the
   Joystick. This is separate from making sure the joystick module is
   initialized. When multiple Joysticks objects are created for the same
   physical joystick device (i.e., they have the same ``ID`` number), the state
   and values for those Joystick objects will be shared.

   The Joystick object allows you to get information about the types of
   controls on a joystick device. Once the device is initialized the Pygame
   event queue will start receiving events about its input.

   You can call the ``Joystick.get_name()`` and ``Joystick.get_id()`` functions
   without initializing the Joystick object.

   .. method:: init

      | :sl:`initialize the Joystick`
      | :sg:`init() -> None`

      The Joystick must be initialized to get most of the information about the
      controls. While the Joystick is initialized the Pygame event queue will
      receive events from the Joystick input.

      It is safe to call this more than once.

      .. ## Joystick.init ##

   .. method:: quit

      | :sl:`uninitialize the Joystick`
      | :sg:`quit() -> None`

      This will unitialize a Joystick. After this the Pygame event queue will
      no longer receive events from the device.

      It is safe to call this more than once.

      .. ## Joystick.quit ##

   .. method:: get_init

      | :sl:`check if the Joystick is initialized`
      | :sg:`get_init() -> bool`

      Returns True if the ``init()`` method has already been called on this
      Joystick object.

      .. ## Joystick.get_init ##

   .. method:: get_id

      | :sl:`get the Joystick ID`
      | :sg:`get_id() -> int`

      Returns the integer ``ID`` that represents this device. This is the same
      value that was passed to the ``Joystick()`` constructor. This method can
      safely be called while the Joystick is not initialized.

      .. ## Joystick.get_id ##

   .. method:: get_name

      | :sl:`get the Joystick system name`
      | :sg:`get_name() -> string`

      Returns the system name for this joystick device. It is unknown what name
      the system will give to the Joystick, but it should be a unique name that
      identifies the device. This method can safely be called while the
      Joystick is not initialized.

      .. ## Joystick.get_name ##

   .. method:: get_numaxes

      | :sl:`get the number of axes on a Joystick`
      | :sg:`get_numaxes() -> int`

      Returns the number of input axes are on a Joystick. There will usually be
      two for the position. Controls like rudders and throttles are treated as
      additional axes.

      The ``pygame.JOYAXISMOTION`` events will be in the range from -1.0 to
      1.0. A value of 0.0 means the axis is centered. Gamepad devices will
      usually be -1, 0, or 1 with no values in between. Older analog joystick
      axes will not always use the full -1 to 1 range, and the centered value
      will be some area around 0. Analog joysticks usually have a bit of noise
      in their axis, which will generate a lot of rapid small motion events.

      .. ## Joystick.get_numaxes ##

   .. method:: get_axis

      | :sl:`get the current position of an axis`
      | :sg:`get_axis(axis_number) -> float`

      Returns the current position of a joystick axis. The value will range
      from -1 to 1 with a value of 0 being centered. You may want to take into
      account some tolerance to handle jitter, and joystick drift may keep the
      joystick from centering at 0 or using the full range of position values.

      The axis number must be an integer from zero to get_numaxes()-1.

      .. ## Joystick.get_axis ##

   .. method:: get_numballs

      | :sl:`get the number of trackballs on a Joystick`
      | :sg:`get_numballs() -> int`

      Returns the number of trackball devices on a Joystick. These devices work
      similar to a mouse but they have no absolute position; they only have
      relative amounts of movement.

      The ``pygame.JOYBALLMOTION`` event will be sent when the trackball is
      rolled. It will report the amount of movement on the trackball.

      .. ## Joystick.get_numballs ##

   .. method:: get_ball

      | :sl:`get the relative position of a trackball`
      | :sg:`get_ball(ball_number) -> x, y`

      Returns the relative movement of a joystick button. The value is a x, y
      pair holding the relative movement since the last call to get_ball.

      The ball number must be an integer from zero to get_numballs()-1.

      .. ## Joystick.get_ball ##

   .. method:: get_numbuttons

      | :sl:`get the number of buttons on a Joystick`
      | :sg:`get_numbuttons() -> int`

      Returns the number of pushable buttons on the joystick. These buttons
      have a boolean (on or off) state.

      Buttons generate a ``pygame.JOYBUTTONDOWN`` and ``pygame.JOYBUTTONUP``
      event when they are pressed and released.

      .. ## Joystick.get_numbuttons ##

   .. method:: get_button

      | :sl:`get the current button state`
      | :sg:`get_button(button) -> bool`

      Returns the current state of a joystick button.

      .. ## Joystick.get_button ##

   .. method:: get_numhats

      | :sl:`get the number of hat controls on a Joystick`
      | :sg:`get_numhats() -> int`

      Returns the number of joystick hats on a Joystick. Hat devices are like
      miniature digital joysticks on a joystick. Each hat has two axes of
      input.

      The ``pygame.JOYHATMOTION`` event is generated when the hat changes
      position. The position attribute for the event contains a pair of values
      that are either -1, 0, or 1. A position of (0, 0) means the hat is
      centered.

      .. ## Joystick.get_numhats ##

   .. method:: get_hat

      | :sl:`get the position of a joystick hat`
      | :sg:`get_hat(hat_number) -> x, y`

      Returns the current position of a position hat. The position is given as
      two values representing the ``X`` and ``Y`` position for the hat. (0, 0)
      means centered. A value of -1 means left/down and a value of 1 means
      right/up: so (-1, 0) means left; (1, 0) means right; (0, 1) means up; (1,
      1) means upper-right; etc.

      This value is digital, ``i.e.``, each coordinate can be -1, 0 or 1 but
      never in-between.

      The hat number must be between 0 and get_numhats()-1.

      .. ## Joystick.get_hat ##

   .. ## pygame.joystick.Joystick ##

.. ## pygame.joystick ##

.. figure:: code_examples/joystick_calls.png
   :scale: 100 %
   :alt: joystick module example

   Example code for joystick module.
   
.. literalinclude:: code_examples/joystick_calls.py
   