keymanager.js

Table of Contents

  1. accidental.js
  2. annotation.js
  3. articulation.js
  4. barnote.js
  5. beam.js
  6. bend.js
  7. boundingbox.js
  8. boundingboxcomputation.js
  9. canvascontext.js
  10. clef.js
  11. clefnote.js
  12. crescendo.js
  13. curve.js
  14. dot.js
  15. easyscore.js
  16. element.js
  17. factory.js
  18. formatter.js
  19. fraction.js
  20. frethandfinger.js
  21. ghostnote.js
  22. glyph.js
  23. gracenote.js
  24. gracenotegroup.js
  25. gracetabnote.js
  26. index.js
  27. keymanager.js
  28. keysignature.js
  29. modifier.js
  30. modifiercontext.js
  31. music.js
  32. note.js
  33. notehead.js
  34. notesubgroup.js
  35. ornament.js
  36. parser.js
  37. pedalmarking.js
  38. raphaelcontext.js
  39. renderer.js
  40. stave.js
  41. stavebarline.js
  42. staveconnector.js
  43. stavehairpin.js
  44. staveline.js
  45. stavemodifier.js
  46. stavenote.js
  47. staverepetition.js
  48. stavesection.js
  49. stavetempo.js
  50. stavetext.js
  51. stavetie.js
  52. stavevolta.js
  53. stem.js
  54. stemmablenote.js
  55. stringnumber.js
  56. strokes.js
  57. svgcontext.js
  58. system.js
  59. tables.js
  60. tabnote.js
  61. tabslide.js
  62. tabstave.js
  63. tabtie.js
  64. textbracket.js
  65. textdynamics.js
  66. textnote.js
  67. tickable.js
  68. tickcontext.js
  69. timesignature.js
  70. timesignote.js
  71. tremolo.js
  72. tuning.js
  73. tuplet.js
  74. vex.js
  75. vibrato.js
  76. vibratobracket.js
  77. voice.js
  78. voicegroup.js

VexFlow - Copyright (c) Mohit Muthanna 2010.

Description

This class implements diatonic key management.

import { Vex } from './vex';
import { Music } from './music';

export class KeyManager {
  constructor(key) {
    this.music = new Music();
    this.setKey(key);
  }

  setKey(key) {
    this.key = key;
    this.reset();
    return this;
  }

  getKey() { return this.key; }

  reset() {
    this.keyParts = this.music.getKeyParts(this.key);

    this.keyString = this.keyParts.root;
    if (this.keyParts.accidental) this.keyString += this.keyParts.accidental;

    const is_supported_type = Music.scaleTypes[this.keyParts.type];
    if (!is_supported_type) {
      throw new Vex.RERR('BadArguments', `Unsupported key type: ${this.key}`);
    }

    this.scale = this.music.getScaleTones(
      this.music.getNoteValue(this.keyString),
      Music.scaleTypes[this.keyParts.type]
    );

    this.scaleMap = {};
    this.scaleMapByValue = {};
    this.originalScaleMapByValue = {};

    const noteLocation = Music.root_indices[this.keyParts.root];

    for (let i = 0; i < Music.roots.length; ++i) {
      const index = (noteLocation + i) % Music.roots.length;
      const rootName = Music.roots[index];

      const noteName = this.music.getRelativeNoteName(rootName, this.scale[i]);
      this.scaleMap[rootName] = noteName;
      this.scaleMapByValue[this.scale[i]] = noteName;
      this.originalScaleMapByValue[this.scale[i]] = noteName;
    }

    return this;
  }

  getAccidental(key) {
    const root = this.music.getKeyParts(key).root;
    const parts = this.music.getNoteParts(this.scaleMap[root]);

    return {
      note: this.scaleMap[root],
      accidental: parts.accidental,
    };
  }

  selectNote(note) {
    note = note.toLowerCase();
    const parts = this.music.getNoteParts(note);

First look for matching note in our altered scale

    const scaleNote = this.scaleMap[parts.root];
    const modparts = this.music.getNoteParts(scaleNote);

    if (scaleNote === note) {
      return {
        'note': scaleNote,
        'accidental': parts.accidental,
        'change': false,
      };
    }

Then search for a note of equivalent value in our altered scale

    const valueNote = this.scaleMapByValue[this.music.getNoteValue(note)];
    if (valueNote != null) {
      return {
        'note': valueNote,
        'accidental': this.music.getNoteParts(valueNote).accidental,
        'change': false,
      };
    }

Then search for a note of equivalent value in the original scale

    const originalValueNote = this.originalScaleMapByValue[
      this.music.getNoteValue(note)];
    if (originalValueNote != null) {
      this.scaleMap[modparts.root] = originalValueNote;
      delete this.scaleMapByValue[this.music.getNoteValue(scaleNote)];
      this.scaleMapByValue[this.music.getNoteValue(note)] = originalValueNote;
      return {
        'note': originalValueNote,
        'accidental': this.music.getNoteParts(originalValueNote).accidental,
        'change': true,
      };
    }

Then try to unmodify a currently modified note.

    if (modparts.root === note) {
      delete this.scaleMapByValue[this.music.getNoteValue(this.scaleMap[parts.root])];
      this.scaleMapByValue[this.music.getNoteValue(modparts.root)] =  modparts.root;
      this.scaleMap[modparts.root] = modparts.root;
      return {
        'note': modparts.root,
        'accidental': null,
        'change': true,
      };
    }

Last resort – shitshoot

    delete this.scaleMapByValue[this.music.getNoteValue(this.scaleMap[parts.root])];
    this.scaleMapByValue[this.music.getNoteValue(note)] = note;

    delete this.scaleMap[modparts.root];
    this.scaleMap[modparts.root] = note;

    return {
      note,
      'accidental': parts.accidental,
      'change': true,
    };
  }
}
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