README.md

ex-portmidi

Need to catch up? Have a look at the changelog! 🚀

ex-portmidi is a wrapper for the PortMidi C library, that provides some nice abstractions to (write to|listen on) MIDI devices.

Installation

Add portmidi to your list of dependencies in mix.exs, and ensure that portmidi is started before your application:

def deps do
  [{:portmidi, "~> 5.0"}]
end

def application do
  [applications: [:portmidi]]
end

Configuration

If needed, the input buffer size can be set, in your config.exs:

  config :portmidi, buffer_size: 1024

By default, this value is 256.

Usage

To send MIDI events to a MIDI device:

iex(1)> {:ok, output} = PortMidi.open(:output, "Launchpad Mini")
{:ok, #PID<0.172.0>}

iex(2)> PortMidi.write(output, {176, 0, 127})
:ok

iex(3)> PortMidi.write(output, {{176, 0, 127}, 123}) # with timestamp
:ok

iex(4)> PortMidi.write(output, [
iex(5)>   {{176, 0, 127}, 123},
iex(6)>   {{178, 0, 127}, 128}
iex(7)> ]) # as a sequence of events (more efficient)
:ok

iex(8)> PortMidi.close(:output, output)
:ok

To listen for MIDI events from a MIDI device:

iex(1)> {:ok, input} = PortMidi.open(:input, "Launchpad Mini")
{:ok, #PID<0.103.0>}

ex(2)> PortMidi.listen(input, self)
:ok

iex(3)> receive do
...(3)>   {^input, event} -> IO.inspect(event)
...(3)> end
{144, 112, 127}

iex(4)> PortMidi.close(:input, input)
:ok

To list all connected devices:

ex(1)> PortMidi.devices
%{input: [%PortMidi.Device{input: 1, interf: "CoreMIDI", name: "Launchpad Mini",
    opened: 0, output: 0}],
  output: [%PortMidi.Device{input: 0, interf: "CoreMIDI",
    name: "Launchpad Mini", opened: 0, output: 1}]}

For more details, check out the Hexdocs.