qambi/dist/midi_event.js

MIDI sequencer, loads MIDI files, can record and playback MIDI, uses WebMIDI and WebAudio

'use strict';

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.MIDIEvent = undefined;

var _createClass = function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; }(); // @ flow


var _note = require('./note');

var _settings = require('./settings');

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

var instanceIndex = 0;

var MIDIEvent = exports.MIDIEvent = function () {
  function MIDIEvent(ticks, type, data1) {
    var data2 = arguments.length > 3 && arguments[3] !== undefined ? arguments[3] : -1;
    var channel = arguments.length > 4 && arguments[4] !== undefined ? arguments[4] : 0;

    _classCallCheck(this, MIDIEvent);

    this.id = this.constructor.name + '_' + instanceIndex++ + '_' + new Date().getTime();
    this.ticks = ticks;
    this.data1 = data1;
    this.data2 = data2;
    this.pitch = (0, _settings.getSettings)().pitch;

    /* test whether type is a status byte or a command: */

    // 1. the higher 4 bits of the status byte form the command
    this.type = (type >> 4) * 16;
    //this.type = this.command = (type >> 4) * 16

    // 2. filter channel events
    if (this.type >= 0x80 && this.type <= 0xE0) {
      // 3. get the channel number
      if (channel > 0) {
        // a channel is set, this overrules the channel number in the status byte
        this.channel = channel;
      } else {
        // extract the channel from the status byte: the lower 4 bits of the status byte form the channel number
        this.channel = type & 0xF;
      }
      //this.status = this.command + this.channel
    } else {
      // 4. not a channel event, set the type and command to the value of type as provided in the constructor
      this.type = type;
      //this.type = this.command = type
      this.channel = 0; // any
    }
    //console.log(type, this.type, this.command, this.status, this.channel, this.id)

    // sometimes NOTE_OFF events are sent as NOTE_ON events with a 0 velocity value
    if (type === 144 && data2 === 0) {
      this.type = 128;
    }

    this._part = null;
    this._track = null;
    this._song = null;

    if (type === 144 || type === 128) {
      var _getNoteData = (0, _note.getNoteData)({ number: data1 });

      this.noteName = _getNoteData.name;
      this.fullNoteName = _getNoteData.fullName;
      this.frequency = _getNoteData.frequency;
      this.octave = _getNoteData.octave;
    }
    //@TODO: add all other properties
  }

  _createClass(MIDIEvent, [{
    key: 'copy',
    value: function copy() {
      var m = new MIDIEvent(this.ticks, this.type, this.data1, this.data2);
      return m;
    }
  }, {
    key: 'transpose',
    value: function transpose(amount) {
      // may be better if not a public method?
      this.data1 += amount;
      this.frequency = this.pitch * Math.pow(2, (this.data1 - 69) / 12);
    }
  }, {
    key: 'updatePitch',
    value: function updatePitch(newPitch) {
      if (newPitch === this.pitch) {
        return;
      }
      this.pitch = newPitch;
      this.transpose(0);
    }
  }, {
    key: 'move',
    value: function move(ticks) {
      this.ticks += ticks;
      if (this.midiNote) {
        this.midiNote.update();
      }
    }
  }, {
    key: 'moveTo',
    value: function moveTo(ticks) {
      this.ticks = ticks;
      if (this.midiNote) {
        this.midiNote.update();
      }
    }
  }]);

  return MIDIEvent;
}();

/*
export function deleteMIDIEvent(event){
  //event.note = null
  event.note = null
  event = null
}
*/