View Source InputEvent (input_event v1.4.2)

Elixir interface to Linux input event devices

Summary

Types

code()

Event code

code_number()
event()

Event structure

events_message()

Message that is sent to the caller when input event received

options()

Options for the InputEvent Genserver

type()

Event type

type_name()

The type of event

type_number()

An unknown event type

value()

Event value

Functions

child_spec(init_arg)

Returns a specification to start this module under a supervisor.

enumerate()

Scan the system for input devices and return information on each one.

info(server)

Return information about this input event device

start_link(path)

Start a GenServer that reports events from the specified input event device

stop(server)

Stop the InputEvent GenServer.

Types

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code()

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@type code() :: atom() | code_number()

Event code

Usually these are translated to an atom that corresponds with the Linux event code. Event codes depend on the event type.

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code_number()

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@type code_number() :: 0..65535
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event()

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@type event() :: {type(), code(), value()}

Event structure

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events_message()

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@type events_message() :: {:input_event, String.t(), [event()]}

Message that is sent to the caller when input event received

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options()

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@type options() :: [
  path: String.t(),
  grab: boolean(),
  receiver: pid() | atom(),
  repeat_delay: pos_integer(),
  repeat_period: pos_integer()
]

Options for the InputEvent Genserver

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type()

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@type type() :: type_name() | type_number()

Event type

Usually these are translated to an atom that corresponds with the Linux event type.

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type_name()

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@type type_name() ::
  :ev_syn
  | :ev_key
  | :ev_rel
  | :ev_abs
  | :ev_msc
  | :ev_sw
  | :ev_led
  | :ev_snd
  | :ev_rep
  | :ev_ff
  | :ev_pwr
  | :ev_ff_status

The type of event

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type_number()

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@type type_number() :: 0..65535

An unknown event type

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value()

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@type value() :: integer()

Event value

See the event type and code for how to interpret the value. For example, it could be a 0 or 1 signifying a key press or release, or it could be an x or y coordinate or delta.

Functions

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child_spec(init_arg)

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Returns a specification to start this module under a supervisor.

See Supervisor.

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enumerate()

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@spec enumerate() :: [{String.t(), InputEvent.Info.t()}]

Scan the system for input devices and return information on each one.

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info(server)

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@spec info(GenServer.server()) :: InputEvent.Info.t()

Return information about this input event device

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start_link(path)

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@spec start_link(String.t() | options()) :: GenServer.on_start()

Start a GenServer that reports events from the specified input event device

Options:

  • :path - the path to the input event device (e.g., "/dev/input/event0")
  • :grab - set to true to prevent events from being passed to other applications (defaults to false)
  • :repeat_delay - delay in milliseconds before a key press repeats
  • :repeat_period - period in milliseconds in which a key press will repeat
  • :receiver - the pid or name of the process that receives events (defaults to the process that calls start_link/1

Note that passing the device path rather than a keyword list to start_link/1 is deprecated.

When adjusting the key repeat rate, you must set BOTH :repeat_delay and :repeat_period for input_event to make the change. Be careful setting repeat timing in multiple places on the same device path! You might override your own settings!

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stop(server)

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@spec stop(GenServer.server()) :: :ok

Stop the InputEvent GenServer.