getLongestFitWord(words) {
    let w = 0;

    while (w < words.length) {
      if (this.overMaxWidth(words.slice(0, w))) break;
      w++;
    }

    return w;
  }
Determine the longest part of the string which still fits in the
current max width.
@param {Array} words Array of strings signifying a text lines
@returns {number} index of first item in string making string go over max