Letter render on top of each other.

[haszzam]

Hi i got this weird behavior for multiple fonts before and i have no idea what's wrong. for most fonts it works perfectly but for others, the letters just crumble on top pf each other like you can see here

[swingerman]

Not 100% sure why but for some fonts Opentype mutates the glyph data after already calculated all metrics and overwrites the advance width with NaN. I use this snippet to avoid this:

Object.defineProperty(Glyph.prototype, 'advanceWidth', {
  get() {
    return this.storedAdvanceWidth;
  },
  set(value) {
    if (!Number.isNaN(value)) {
      this.storedAdvanceWidth = value;
    }
  },
});

[Connum]

@Hassan-Azzam @swingerman could you please provide at least one font where this happens?