midi-topaz

Topaz

MIDI syncable tempo in Ruby

Installation

gem install midi-topaz

or with Bundler, add this to your Gemfile

gem "midi-topaz"

Usage

require "topaz"

For demonstration purposes, here's a mock sequencer class and object

class Sequencer

  def step
    @i ||= 0
    puts "step #{@i+=1}"
  end

end

sequencer = Sequencer.new

The Topaz clock can now be used to step that sequencer. Timed by Topaz, the passed in block will be called repeatedly at 130 BPM

@clock = Topaz::Clock.new(130) { sequencer.step }

A MIDI device can be used to time and control the tempo. To accomplish this, pass a unimidi input to the Clock constructor

@input = UniMIDI::Input.gets # select a midi input

@clock = Topaz::Clock.new(@input) { sequencer.step }

Topaz can also act as a MIDI master clock. If a MIDI output is passed to Topaz, MIDI clock messages will automatically be sent to that output at the appropriate time

@output = UniMIDI::Output.gets # select a midi output

@clock = Topaz::Clock.new(120, :midi => @output) do
  sequencer.step
end

Input and multiple outputs can be used simultaneously, for MIDI thru

@clock = Topaz::Clock.new(@input, :midi => [@output1, @output2]) do
  sequencer.step
end

Once the Clock object is initialized, start the clock

@clock.start

Topaz will run in a background thread if the option :background => true is passed in.

@clock.start(:background => true)

If you are syncing to an external MIDI source, this will start the listener waiting for MIDI clock messages.

You can view the current tempo:

@clock.tempo
  => 132.422000

Pass in a block that will stop the clock when it evaluates to true

@clock.trigger.stop { @i == 20 }

Documentation

• examples
• rdoc

Author

• Ari Russo <ari.russo at gmail.com>

License

Apache 2.0, See the file LICENSE

Copyright (c) 2011-2015 Ari Russo