
Attach (recommended) or Link to PDF file here:
[NAPEN16171380959.pdf](https://github.com/mozilla/pdf.js/files/6143802/NAPEN16171380959.pdf)

Configuration:
- Web browser and its version: Firefox 88 Nightly
- Operating system and its version: Windows 10
- PDF.js version:
- Is a browser extension: No

What went wrong? (add screenshot)
![](https://user-media-prod-cdn.itsre-sumo.mozilla.net/uploads/images/2021-03-15-10-58-27-ce2796.png)


"hmtx",
        (function fontFieldsHmtx() {
          var charstrings = font.charstrings;
          var cffWidths = font.cff ? font.cff.widths : null;
          var hmtx = "\x00\x00\x00\x00"; 
          for (let i = 1, ii = numGlyphs; i < ii; i++) {
            var width = 0;
            if (charstrings) {
              var charstring = charstrings[i - 1];
              width = "width" in charstring ? charstring.width : 0;
            } else if (cffWidths) {
              width = Math.ceil(cffWidths[i] || 0);
            }
            hmtx += string16(width) + string16(0);
          }
          return hmtx;
        })()
      );
      
      builder.addTable(
        "maxp",
        "\x00\x00\x50\x00" + string16(numGlyphs) 
      ); 
      
      builder.addTable("name", createNameTable(fontName));
      
      builder.addTable("post", createPostTable(properties));
      return builder.toArray();
    },
    get spaceWidth() {