vexflow/src/notesubgroup.js

A JavaScript library for rendering music notation and guitar tablature

// [VexFlow](http://vexflow.com) - Copyright (c) Mohit Muthanna 2010.
// Author Taehoon Moon 2016
//
// ## Description
//
// This file implements `NoteSubGroup` which is used to format and
// render notes as a `Modifier`
// ex) ClefNote, TimeSigNote and BarNote.

import { Vex } from './vex';
import { Flow } from './tables';
import { Modifier } from './modifier';
import { Formatter } from './formatter';
import { Voice } from './voice';

export class NoteSubGroup extends Modifier {
  static get CATEGORY() { return 'notesubgroup'; }

  // Arrange groups inside a `ModifierContext`
  static format(groups, state) {
    if (!groups || groups.length === 0) return false;

    let width = 0;
    for (let i = 0; i < groups.length; ++i) {
      const group = groups[i];
      group.preFormat();
      width += group.getWidth();
    }

    state.left_shift += width;
    return true;
  }

  constructor(subNotes) {
    super();
    this.setAttribute('type', 'NoteSubGroup');

    this.note = null;
    this.index = null;
    this.position = Modifier.Position.LEFT;
    this.subNotes = subNotes;
    this.subNotes.forEach(subNote => { subNote.ignore_ticks = false; });
    this.width = 0;
    this.preFormatted = false;

    this.formatter = new Formatter();
    this.voice = new Voice({
      num_beats: 4,
      beat_value: 4,
      resolution: Flow.RESOLUTION,
    }).setStrict(false);

    this.voice.addTickables(this.subNotes);

    return this;
  }

  getCategory() { return NoteSubGroup.CATEGORY; }

  preFormat() {
    if (this.preFormatted) return;

    this.formatter.joinVoices([this.voice]).format([this.voice], 0);
    this.setWidth(this.formatter.getMinTotalWidth());
    this.preFormatted = true;
  }

  setNote(note) {
    this.note = note;
  }
  setWidth(width) {
    this.width = width;
  }
  getWidth() {
    return this.width;
  }

  draw() {
    this.checkContext();

    const note = this.getNote();

    if (!(note && (this.index !== null))) {
      throw new Vex.RuntimeError('NoAttachedNote',
        "Can't draw notes without a parent note and parent note index.");
    }

    this.setRendered();
    this.alignSubNotesWithNote(this.subNotes, note); // Modifier function

    // Draw notes
    this.subNotes.forEach(subNote => subNote.setContext(this.context).draw());
  }
}