= launchpad

This gem provides an interface to access novation's launchpad programmatically. LEDs can be lighted and button presses can be responded to. Internally, launchpad's MIDI input/output is used to accomplish this.

The interfaces should be rather stable now, so experiment with them and comment on their usability. This still is work in progress. If you need anything or think the interfaces could be improved in any way, please contact me.

Sometimes, the launchpad won't react to anything or react to/light up the wrong LEDs. Don't despair, just dis- and reconnect the thing. It seems that some (unexpected) MIDI signals make it hickup.


== Requirements

* Roger B. Dannenberg's {portmidi library}[http://sourceforge.net/projects/portmedia/]
* Jan Krutisch's {portmidi gem}[http://github.com/halfbyte/portmidi]


== Installation

The gem is hosted on Gemcutter[http://gemcutter.org/], so in order to use it, you're gonna install the gemcutter gem (for details, see their site):

  gem install gemcutter
  gem tumble

After that, it's a simple gem install:

  gem install launchpad


== Usage

There are two main entry points:

* require 'launchpad/device', providing Launchpad::Device, which handles all the basic input/output stuff
* require 'launchpad/interaction' or just 'launchpad', additionally providing Launchpad::Interaction, which lets you respond to actions (button presses/releases)

This is a simple example (only requiring the device for output) that switches on all LEDs (for testing), resets the launchpad again and then lights the grid button at position 4/4 (from top left).

  require 'rubygems'
  require 'launchpad/device'
  
  device = Launchpad::Device.new
  device.test_leds
  sleep 1
  device.reset
  sleep 1
  device.change :grid, :x => 4, :y => 4, :red => :high, :green => :low

This is an interaction example lighting all grid buttons in red when pressed and keeping them lit.

  require 'rubygems'
  require 'launchpad'
  
  interaction = Launchpad::Interaction.new
  interaction.response_to(:grid, :down) do |interaction, action|
    interaction.device.change(:grid, action.merge(:red => :high))
  end
  
  interaction.start


For more details, see the examples. examples/color_picker.rb is the most complex example with interaction.


== Near future plans

* close devices properly as soon as halfbyte's pulled my changes to portmidi
* interaction responses for presses on single grid buttons/button areas
* double buffering
* bitmap rendering


== Copyright

Copyright (c) 2009 Thomas Jachmann. See LICENSE for details.