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import Flutter
import CoreMIDI
import AVFAudio
import AVFoundation
import CoreAudio
public class FlutterMidiProPlugin: NSObject, FlutterPlugin {
var _arguments = [String: Any]()
var audioEngine = AVAudioEngine()
var samplerNode = AVAudioUnitSampler()
var tempFileURL = FileManager.default.temporaryDirectory.appendingPathComponent("temp.sf2")
public static func register(with registrar: FlutterPluginRegistrar) {
let channel = FlutterMethodChannel(name: "flutter_midi_pro", binaryMessenger: registrar.messenger())
let instance = FlutterMidiProPlugin()
registrar.addMethodCallDelegate(instance, channel: channel)
}
public func handle(_ call: FlutterMethodCall, result: @escaping FlutterResult) {
switch call.method {
case "loadSoundfont":
guard let map = call.arguments as? Dictionary<String, Any>,
let sf2Data = map["sf2Data"] as? FlutterStandardTypedData else {
result(FlutterError(code: "INVALID_ARGUMENT", message: "sf2Data is required and must be a FlutterStandardTypedData", details: nil))
return
}
let soundfontData = sf2Data.data as Data
do {
try soundfontData.write(to: tempFileURL, options: .atomic)
} catch {
print("Error writing temp file: \(error)")
return
}
do {
audioEngine.attach(samplerNode)
audioEngine.connect(samplerNode, to: audioEngine.mainMixerNode, format:nil)
try audioEngine.start()
// implementing an instrument from a soundfont into a samplerNode
try samplerNode.loadSoundBankInstrument(at: tempFileURL, program: 0, bankMSB: UInt8(kAUSampler_DefaultMelodicBankMSB), bankLSB: UInt8(kAUSampler_DefaultBankLSB))
} catch {
print("Error preparing MIDI: \(error.localizedDescription)")
}
result("Soundfont changed successfully")
case "getInstruments":
var instruments = [String]()
for i in 1...16 {
instruments.append("\(i)")
}
result(instruments)
case "playMidiNote":
_arguments = call.arguments as! [String : Any];
let note = UInt8(_arguments["note"] as! Int)
let velocity = UInt8(_arguments["velocity"] as! Int)
let channel = UInt8(_arguments["channel"] as! Int)
samplerNode.startNote(note, withVelocity: velocity, onChannel: channel)
result(nil)
case "stopMidiNote":
_arguments = call.arguments as! [String : Any];
let note = UInt8(_arguments["note"] as! Int)
let channel = UInt8(_arguments["channel"] as! Int)
samplerNode.stopNote(note, onChannel: channel)
result(nil)
default:
result(FlutterMethodNotImplemented)
break
}
}
}