Class AlphaSynthWrapper

packages/alphatab/src/synth/AlphaSynthWrapper.ts:34–478

 * @internal
 */
export class AlphaSynthWrapper implements IAlphaSynth {
    // relevant state information we want to remember when switching between player instances
    private _masterVolume: number = 1;
    private _metronomeVolume: number = 0;
    private _countInVolume: number = 0;
    private _playbackSpeed: number = 1;
    private _isLooping: boolean = false;
    private _midiEventsPlayedFilter: MidiEventType[] = [];

    private _instance?: IAlphaSynth;
    private _instanceEventUnregister?: (() => void)[];

    public midiTickShift = 0;

    public constructor() {
        this.ready = new EventEmitter(() => this.isReady);
        this.readyForPlayback = new EventEmitter(() => this.isReadyForPlayback);
        this.midiLoaded = new EventEmitterOfT<PositionChangedEventArgs>(() => {
            return this._instance?.loadedMidiInfo ?? null;
        });
        this.stateChanged = new EventEmitterOfT<PlayerStateChangedEventArgs>(() => {
            return new PlayerStateChangedEventArgs(this.state, false);
        });
        this.positionChanged = new EventEmitterOfT<PositionChangedEventArgs>(() => {
            return this.currentPosition;
        });
        this.playbackRangeChanged = new EventEmitterOfT<PlaybackRangeChangedEventArgs>(() => {
            const range = this.playbackRange;
            if (range) {
                return new PlaybackRangeChangedEventArgs(range);
            }
            return null;
        });
    }

    public get instance(): IAlphaSynth | undefined {
        return this._instance;
    }

    public set instance(value: IAlphaSynth | undefined) {
        this._instance = value;

        // unregister all events from previous instance
        const unregister = this._instanceEventUnregister;
        if (unregister) {
            for (const e of unregister) {
                e();
            }
        }

        if (value) {
            // regsiter to events of new player and forward them to existing listeners
            const newUnregister: (() => void)[] = [];
            newUnregister.push(value.ready.on(() => (this.ready as EventEmitter).trigger()));
            newUnregister.push(value.readyForPlayback.on(() => (this.readyForPlayback as EventEmitter).trigger()));
            newUnregister.push(value.finished.on(() => (this.finished as EventEmitter).trigger()));
            newUnregister.push(value.soundFontLoaded.on(() => (this.soundFontLoaded as EventEmitter).trigger()));
            newUnregister.push(