getLongestFit(words) {
    let text = "";
    let w = 0;

    while (w < words.length) {
      const pre = text === "" ? "" : " ";
      const newText = text + pre + words[w];

      if (this.overMaxWidth(newText)) break;
      text = newText;
      w++;
    }

    return w;
  }
Determine the longest part of the sentence 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
@private