Making OT/TTF layout features work in MS Word 2010

Matthew Butterick

I'm not the first to get tripped up by this. But I came up with a solution suitable for the cheap & lazy—er, economical & efficient.

For bad and arbitrary reasons, OT/TTF fonts with layout features are only recognized as such in Windows if they have a DSIG (digital signature) table. Without this table, they behave as normal TTF fonts (i.e., none of the layout features work). This is not true of OT/CFF fonts, which need no DSIG table.

Windows customers can use OT/CFF fonts. But MS Office, and MS Word in particular, still works better with TT-based fonts. For instance, for bad and arbitrary reasons, the built-in PDF generator in Word will not embed OT/CFF fonts, only OT/TTF.

To make a DSIG, one solution is to buy an actual digital signature from a certificate authority. Fontlab, for instance, can generate the DSIG table if you have the signature files. (Don't know how it's handled in Glyphs or Robofont.) But this is about $200 per year. Digitally signing your fonts has other ostensible benefits, so if you like that, great. To me, it's a lot to pay just to get OT/TTF fonts to do what they should've been able to do in the first place, which is: work.

FontForge can put in a dummy DSIG table, but that requires dealing with FontForge.

If you have ttx installed, however, you can do it this way:

Create a ttx file with a dummy DSIG table, like so:

<?xml version="1.0" encoding="ISO-8859-1"?>
<ttFont sfntVersion="\x00\x01\x00\x00" ttLibVersion="2.2">
<DSIG>
   <hexdata>
     00000001 00000000  
   </hexdata>
</DSIG>
</ttFont>

Then you can merge this into your OT/TTF like this:

ttx -m font.ttf dsig.ttx

This will decompile the ttf, add the DSIG table, and recompile in one step. Then the font will work as intended in MS Office (or so I have found in my testing thus far.) This is also easy to incorporate into other scripts.

Of course, this is not a real digital signature, but it's sufficient to convince Windows that the font has a valid DSIG table.

(Hat tip to Ross Mills for pointing me in the right direction.)

Paul van der Laan

This topic, and a similar solution using different tools was earlier discussed at Typophile: http://typophile.com/node/29770

Paul van der Laan

This topic, and a similar solution using different tools was earlier discussed at Typophile: http://typophile.com/node/29770

Thomas Phinney

It's only kind of the same topic. The lack of an OT icon is a minor/aesthetic issue, compared to losing the actual OpenType feature functionality. I've known about the icon issue for many years, but if there is an actual functionality issue, that's a big deal.

I'll be curious to learn if this affects web fonts, either in IE or in general.

Paul van der Laan

Indeed Thomas, the topic is not exactly similar. But the moment I saw Matthew’s post I just knew I saw that hack somewhere before...

Matthew Butterick

I saw that hack somewhere before

I think of my hack as a humanist revival of a hack from the previous decade.

David Berlow

"...but if there is an actual functionality issue, that's a big deal."

That's odd. When the table was announced in the 90's, all developers were told that fonts without a DSIG would eventually not work at all on Windows. So, this's a fine compromise.

Matthew Butterick

With Office on Windows, for many years a missing DSIG had no meaningful consequences, since Office didn't support OpenType layout features anyhow. That only changed with Office 2010.

Perhaps predictably, Word 2010 still doesn't implement the DSIG restriction consistently: OT/TTF fonts without a DSIG will still show their layout features in the preview window of the Character formatting box, but the layout features won't show up in the document itself. This was the moment of infuriation that started my hacking spree.

Despite the infuriations, Word is nevertheless the most popular typesetting program in the world, and with the addition of layout features, it's actually quite capable.

Nick Shinn

“Popular”?
Like income tax.

David Berlow

Word is nevertheless the most popular typesetting program in the world

Huh. I'da thought it'd be some web-based thing, like a browser. Where are you getting your stats?

Also, what happens if you output the word-document-with-OT-features-used — to a web site, does any it display in... Firefox?

LetterModeller

'FontForge can put in a dummy DSIG table, but that requires dealing with FontForge.'

In DTL OTMaster one can copy a dummy DSIG table from another TTF, but that requires dealing with DTL OTMaster.

Rainer Erich Scheichelbauer

With fontTools rev.612 (running on 10.8.2), I get a Traceback and a KeyError: 'ulVersion' when I try to merge the table into the TTF as described above. Is it just me or is anybody else also experiencing that problem?

Matthew Butterick

Post the whole traceback please, otherwise no way to ascertain the cause of the error.

Also check if you need this fix.

Rainer Erich Scheichelbauer

Appreciate your help! The fix did not help though. Or did I do it wrong: I changed macUtils.py as indicated and ran sudo python setup.py install again.

mekka$ ttx -m test.otf dsig.ttx 
Compiling "dsig.ttx" to "dsig#1.ttf"...
Parsing 'DSIG' table...
Traceback (most recent call last):
  File "/usr/local/bin/ttx", line 11, in 
    ttx.main(sys.argv[1:])
  File "/Library/Python/2.7/site-packages/FontTools/fontTools/ttx.py", line 295, in main
    process(jobs, options)
  File "/Library/Python/2.7/site-packages/FontTools/fontTools/ttx.py", line 280, in process
    action(input, output, options)
  File "/Library/Python/2.7/site-packages/FontTools/fontTools/ttx.py", line 186, in ttCompile
    ttf.save(output)
  File "/Library/Python/2.7/site-packages/FontTools/fontTools/ttLib/__init__.py", line 200, in save
    self._writeTable(tag, writer, done)
  File "/Library/Python/2.7/site-packages/FontTools/fontTools/ttLib/__init__.py", line 596, in _writeTable
    tabledata = self.getTableData(tag)
  File "/Library/Python/2.7/site-packages/FontTools/fontTools/ttLib/__init__.py", line 608, in getTableData
    return self.tables[tag].compile(self)
  File "/Library/Python/2.7/site-packages/FontTools/fontTools/ttLib/tables/D_S_I_G_.py", line 57, in compile
    packed = sstruct.pack(DSIG_HeaderFormat, self)
  File "/Library/Python/2.7/site-packages/FontTools/sstruct.py", line 69, in pack
    value = object[name]
KeyError: 'ulVersion'

Does this tell you anything?

Matthew Butterick

It tells me you appear to be using a development build of FontTools rather than the latest official release, which is version 2.3.