https://github.com/vrudas/lp4k
Simple API to interact with a Novation Launchpad S (Mini MK3 in future) device. Also provides a web-based emulator.
https://github.com/vrudas/lp4k
Last synced: about 2 months ago
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Simple API to interact with a Novation Launchpad S (Mini MK3 in future) device. Also provides a web-based emulator.
- Host: GitHub
- URL: https://github.com/vrudas/lp4k
- Owner: vrudas
- License: apache-2.0
- Created: 2020-01-20T19:29:20.000Z (over 5 years ago)
- Default Branch: master
- Last Pushed: 2024-12-17T03:08:55.000Z (10 months ago)
- Last Synced: 2024-12-17T05:58:29.237Z (10 months ago)
- Language: Kotlin
- Homepage:
- Size: 850 KB
- Stars: 2
- Watchers: 3
- Forks: 0
- Open Issues: 6
-
Metadata Files:
- Readme: README.md
- Code of conduct: CODE_OF_CONDUCT.md
Awesome Lists containing this project
README
LP4K - A Launchpad API for Kotlin
====
[](https://sonarcloud.io/dashboard?id=vrudas_lp4k)
[](https://sonarcloud.io/dashboard?id=vrudas_lp4k)
[](https://sonarcloud.io/dashboard?id=vrudas_lp4k)
[](https://codecov.io/gh/vrudas/lp4k)
Launchpad is a midi device built by Novation, used to drive computer-assisted music creation applications such as Ableton Live.
The device is a square board with a 8x8 pads grid, surrounded by round command buttons. Pads and buttons can be lit in various tints of yellow, red and green.
This makes the Launchpad an interesting general-purpose I/O device, where a user can press pads and buttons to send commands to an application, and provide feedback with its 8x8 matrix of colored leds.
LP4K is a lightweight Java API (initially based on sources of LP4J project on https://github.com/OlivierCroisier/LP4J) allowing any Java application to interact with a Launchpad Mini MK3.
It also provides a embedded, web-based emulator to allow developers to design and test applications should they not have access to a physical device.
The API is split in 3 submodules :
- lp4k-api : an abstract, high-level API defining how to interact with a Launchpad (LaunchpadClient / LaunchpadListener)
- lp4k-midi : a MIDI implementation of the API, suitable to interact with a physical device.
- lp4k-emulator : a web-based emulator, using SVG and websockets.
How to use LP4K
====
From a developper's perspective, all interaction with LP4K are done through the high-level API.
First, you need to get a reference to a Launchpad :
```kotlin
// Physical device (with auto-detected ports configuration)
val launchpad: Launchpad = MidiLaunchpad(MidiDeviceConfiguration.autodetect())
// Or start the emulator on http://localhost:9000
val launchpad: Launchpad = EmulatorLaunchpad(9000)
```
From this Launchpad instance, you can :
- retrieve a LaunchpadClient, used to send commands TO the device or emulator (mostly to turn on/off the pads or buttons lights),
- set up a LaunchpadListener to react to events.
```kotlin
val client: LaunchpadClient = launchpad.getClient()
launchpad.setListener(ListenerExample())
```
A very simple debugging listener can look like this :
```kotlin
class ListenerExample : LaunchpadListenerAdapter() {
override fun onPadPressed(pad: Pad, timestamp: Long) {
println("Pad pressed : $pad")
}
}
```
A more complex example
====
Listeners can be more complex.
For example, the following Listener sends commands back to the Launchpad to put a yellow light under pads when they are pressed, lighting them off when they are released.
Please also note the use of a CountDownLatch to wait for the user to press the "STOP" button before exiting the application.
```kotlin
import io.lp4k.launchpad.api.*
import io.lp4k.launchpad.midi.MidiDeviceConfiguration
import io.lp4k.launchpad.s.api.ButtonLaunchS
import io.lp4k.launchpad.s.api.ColorLaunchS
import java.util.concurrent.CountDownLatch
private val stop = CountDownLatch(1)
fun main() {
val launchpad = MidiLaunchpad(MidiDeviceConfiguration.autodetect())
val client = launchpad.client
val listener = ListenerExample(client)
launchpad.setListener(listener)
// Set a red light under the STOP button
client.reset()
client.setButtonLight(Button.STOP, Color.RED, BackBufferOperation.NONE)
stop.await()
client.reset()
launchpad.close()
}
class ListenerExample(private val client: LaunchpadClient) : LaunchpadListenerAdapter() {
override fun onPadPressed(pad: Pad, timestamp: Long) {
client.setPadLight(pad, Color.YELLOW, BackBufferOperation.NONE)
}
override fun onPadReleased(pad: Pad, timestamp: Long) {
client.setPadLight(pad, Color.BLACK, BackBufferOperation.NONE)
}
override fun onButtonReleased(button: Button, timestamp: Long) {
client.setButtonLight(button, Color.BLACK, BackBufferOperation.NONE)
when (button) {
Button.STOP -> stop.countDown()
else -> client.setButtonLight(button, Color.BLACK, BackBufferOperation.NONE)
}
}
override fun onButtonPressed(button: Button, timestamp: Long) {
client.setButtonLight(button, Color.GREEN, BackBufferOperation.NONE)
}
}
```