Most annotations, even unsupported ones, render just fine in PDF.js because of their appearance stream. However, there exist PDF files with annotations that do not have an appearance stream (even though this is a deprecated practice). In the latter case, PDF.js displays nothing. We need to have a fallback to a default appearance stream in that case, or create an appearance stream ourselves using the data present for the annotation (such as quad points and color). Below is a list of known PDF files that contain annotations without appearance streams, for which the types are listed.
- <s>http://pdfkit.org/docs/guide.pdf (Underline, Highlight and StrikeOut)</s>
- <s>http://www.plpdf.com/examples/PLPDF-SDK/Simple_Examples/37_Markup_annotation/markup.pdf (Underline, Highlight and StrikeOut)</s>
- <s>https://drive.google.com/file/d/0B6YhVF9p-y2AU0RlYjRKakFQRjQ/view?usp=sharing (Highlight, from #6382)</s>
- https://drive.google.com/open?id=0B6YhVF9p-y2Ad3VsWDRHRkRxY2c (FreeText, from #6246)
- https://drive.google.com/file/d/0B-_5BgJGB33Ea2dQZnpUY2FvYkk/view (FreeText, from #6564)
- http://mirrors.rit.edu/CTAN/macros/latex/contrib/pdfcomment/doc/example.pdf (practically all annotation types, from #1973)

constructor(parameters) {
    super(parameters);
    this.data.annotationType = AnnotationType.INK;
    this.data.inkLists = [];
    const rawInkLists = parameters.dict.getArray("InkList");
    if (!Array.isArray(rawInkLists)) {
      return;
    }
    const xref = parameters.xref;
    for (let i = 0, ii = rawInkLists.length; i < ii; ++i) {
      /
      /
      /
      /
      this.data.inkLists.push([]);
      for (let j = 0, jj = rawInkLists[i].length; j < jj; j += 2) {
        this.data.inkLists[i].push({
          x: xref.fetchIfRef(rawInkLists[i][j]),
          y: xref.fetchIfRef(rawInkLists[i][j + 1]),
        });
      }
    }
    if (!this.appearance) {
      
      const strokeColor = this.color
        ? Array.from(this.color).map(c => c / 255)