VexFlow - Copyright (c) Mohit Muthanna 2010. Author: Mike Corrigan corrigan@gmail.com
This class implements tremolo notation.
import { Vex } from './vex';
import { Modifier } from './modifier';
import { Glyph } from './glyph';
import { GraceNote } from './gracenote';
import { Stem } from './stem';
export class Tremolo extends Modifier {
static get CATEGORY() { return 'tremolo'; }
constructor(num) {
super();
this.setAttribute('type', 'Tremolo');
this.num = num;
this.note = null;
this.index = null;
this.position = Modifier.Position.CENTER;
this.code = 'tremolo1';
}
getCategory() { return Tremolo.CATEGORY; }
draw() {
this.checkContext();
if (!(this.note && this.index != null)) {
throw new Vex.RERR('NoAttachedNote', "Can't draw Tremolo without a note and index.");
}
this.setRendered();
const stemDirection = this.note.getStemDirection();
const start = this.note.getModifierStartXY(this.position, this.index);
let x = start.x;
const isGraceNote = this.note.getCategory() === 'gracenotes';
const scale = isGraceNote ? GraceNote.SCALE : 1;
const category = `tremolo.${isGraceNote ? 'grace' : 'default'}`;
this.y_spacing = this.musicFont.lookupMetric(`${category}.spacing`) * stemDirection;
const height = this.num * this.y_spacing;
let y = this.note.stem.getExtents().baseY - height;
if (stemDirection < 0) {
y += this.musicFont.lookupMetric(`${category}.offsetYStemDown`) * scale;
} else {
y += this.musicFont.lookupMetric(`${category}.offsetYStemUp`) * scale;
}
this.font = {
family: 'Arial',
size: 16 * scale,
weight: '',
};
this.render_options = {
font_scale: this.musicFont.lookupMetric(`${category}.point`),
stroke_px: 3,
stroke_spacing: 10 * scale,
};
x += this.musicFont.lookupMetric(`${category}.offsetXStem${stemDirection === Stem.UP ? 'Up' : 'Down'}`);
for (let i = 0; i < this.num; ++i) {
Glyph.renderGlyph(this.context, x, y, this.render_options.font_scale, this.code, { category });
y += this.y_spacing;
}
}
}