vexflow/src/stavetext.js

A JavaScript library for rendering music notation and guitar tablature

// [VexFlow](http://vexflow.com) - Copyright (c) Mohit Muthanna 2010.
// Author Taehoon Moon 2014

import { Vex } from './vex';
import { StaveModifier } from './stavemodifier';
import { TextNote } from './textnote';

export class StaveText extends StaveModifier {
  static get CATEGORY() { return 'stavetext'; }

  constructor(text, position, options) {
    super();
    this.setAttribute('type', 'StaveText');

    this.setWidth(16);
    this.text = text;
    this.position = position;
    this.options = {
      shift_x: 0,
      shift_y: 0,
      justification: TextNote.Justification.CENTER,
    };
    Vex.Merge(this.options, options);

    this.font = {
      family: 'times',
      size: 16,
      weight: 'normal',
    };
  }

  getCategory() { return StaveText.CATEGORY; }
  setStaveText(text) { this.text = text; return this; }
  setShiftX(x) { this.shift_x = x; return this; }
  setShiftY(y) { this.shift_y = y; return this; }

  setFont(font) {
    Vex.Merge(this.font, font);
  }

  setText(text) {
    this.text = text;
  }

  draw(stave) {
    const ctx = stave.checkContext();
    this.setRendered();

    ctx.save();
    ctx.lineWidth = 2;
    ctx.setFont(this.font.family, this.font.size, this.font.weight);
    const text_width = ctx.measureText('' + this.text).width;

    let x;
    let y;
    const Position = StaveModifier.Position;
    const Justification = TextNote.Justification;
    switch (this.position) {
      case Position.LEFT:
      case Position.RIGHT:
        y = (stave.getYForLine(0) + stave.getBottomLineY()) / 2 + this.options.shift_y;
        if (this.position === Position.LEFT) {
          x = stave.getX() - text_width - 24 + this.options.shift_x;
        } else {
          x = stave.getX() + stave.getWidth() + 24 + this.options.shift_x;
        }
        break;
      case Position.ABOVE:
      case Position.BELOW:
        x = stave.getX() + this.options.shift_x;
        if (this.options.justification === Justification.CENTER) {
          x += stave.getWidth() / 2 - text_width / 2;
        } else if (this.options.justification === Justification.RIGHT) {
          x += stave.getWidth() - text_width;
        }

        if (this.position === Position.ABOVE) {
          y = stave.getYForTopText(2) + this.options.shift_y;
        } else {
          y = stave.getYForBottomText(2) + this.options.shift_y;
        }
        break;
      default:
        throw new Vex.RERR('InvalidPosition', 'Value Must be in Modifier.Position.');
    }

    ctx.fillText('' + this.text, x, y + 4);
    ctx.restore();
    return this;
  }
}