Robofont Help — Kerning Not Exporting

Seb McLauchlan

Hi guys,

I've just started using Metrics Machine after working with Robofont for a while. After some time getting my kerning sorted, I went to test install my font and for some reason the kerning isn't exporting, it appears in my preview window in both Robofont & Metrics Machine, but in any other program its not visible.

Here is a look at my Output window—

makeotf Report

makeotf [Note] Converting source font '/font.otf' to temporary Unix Type1 font file '/font.otf.tmp'.
makeotf [Note] setting the DONT_USE_WIN_LINE_METRICS OS/2 fsSelection bit 7 from fontinfo keyword.
makeotf [Note] setting the WEIGHT_WIDTH_SLOPE_ONLY OS/2 fsSelection bit 8 from fontinfo keyword.
makeotf [Note] setting the OBLIQUE OS/2 fsSelection bit 9 from fontinfo keyword.
makeotf [Note] Writing options file /current.fpr
makeotf [Note] Running makeotfexe with commands:
cd ""
makeotfexe -f font.otf.tmp -o Basis-Light-1.1.otf -ff features -gf glyphOrder -mf menuname -r
makeotfexe [WARNING] [internal] Feature block seen before any language system statement. You should place languagesystem statements before any feature definition [features 3]
makeotfexe [NOTE] Wrote new font file 'Basis-Light-1.1.otf'.


Built release mode font 'Basis-Light-1.1.otf' Revision 0.000

I figure the warning statement is probably the issue, but haven't written anything in my features window, so I don't really understand whats going on?

Any help with this is really appreciated, very close to finishing my first type-family.

Cheers,

Seb

Paul van der Laan

Let MetricsMachine create a KERN feature for your font. Only then will it be usable in OpenType fonts. (This is all explained in the MM manual.)

And please don’t forget to register yourself with your real name in Typedrawers. It’s one of the requirements here.

Seb McLauchlan

Hi Paul,

So I generated a KERN feature inside my font through MetricsMachine, also specified a language statement, and the kerning still isn't being generated on my test-installs. Here's another look at my Output window —

makeotf Report

makeotf [Note] Converting source font '/font.otf' to temporary Unix Type1 font file '/font.otf.tmp'.
makeotf [Note] setting the DONT_USE_WIN_LINE_METRICS OS/2 fsSelection bit 7 from fontinfo keyword.
makeotf [Note] setting the WEIGHT_WIDTH_SLOPE_ONLY OS/2 fsSelection bit 8 from fontinfo keyword.
makeotf [Note] setting the OBLIQUE OS/2 fsSelection bit 9 from fontinfo keyword.
makeotf [Note] Writing options file /current.fpr
makeotf [Note] Running makeotfexe with commands:
cd ""
makeotfexe -f font.otf.tmp -o tmpLoW7xr.otf -ff features -gf glyphOrder -mf menuname -ga
makeotfexe [NOTE] Wrote new font file 'tmpLoW7xr.otf'.


Built development mode font 'tmpLoW7xr.otf'.

Kent Lew

The first thing to check would be if the {kern} GPOS tables are getting written for the font. You can use a TTX dump to inspect the generated font for the presence of a GPOS table.

But the fact that you aren’t getting any error message pertaining to the compilation of the {kern} feature makes me think that this is not the problem.

I seem to recall that in order for many apps to recognize any GPOS lookups (i.e., those that control kerning), there needs to be at least one GSUB lookup (and thus a GSUB table) present.

You mention that you haven’t written any features at all yet, and this may be causing your problem. Try including some sort of basic GSUB feature — {liga} is the typical one to use in this case, even a dummy one — and see if that causes the kerning to be recognized in your apps.

Kent Lew

BTW — if you’re working in Robofont, you shouldn’t need to have MetricsMachine insert a {kern} feature into your font. You can just save your MetricsMachine work directly to the UFO and have it stored natively in the kerning.plist. Robofont will generate the {kern} GPOS tables upon generation.

Having kerning data stored both in the kerning.plist and as an explicit {kern} feature in the features.fea can potentially lead to discrepancies between unsynchronized sets of data if you’re not careful.

Marcos Ojeda

worth doing is checking the following option box in robofont: prefs->misc->save fdk parts next to ufo, so you can examine the generated features file directly, and if it looks sane, you can try building the font from the ufo outright using the afdko and reusing many of the commands you see in the console to pick up the features and so forth. it could be a bug with the embedded fdk in robofont, which hasn't been updated in ~2 revs.

Seb McLauchlan

Hi guys,

So I got the kerning there in InDesign (see attached image), but for some reason it still isn't loading in a web browser or a simpler program like TextEdit. Any clue why this is the case?

@Kent, I've now included a language definition in my features file, is this a GSUB feature? Sorry but this is my first time working in a features file.

Kent Lew

No, a language definition is not a GSUB feature. You need something like

feature liga {
    sub f i by f_i;
} liga;

. . . assuming that you have a f_i ligature glyph. If not (nor anything you can use similarly), then you can just put in a dummy lookup:

feature ss01 {
    sub f by f;
} ss01;

— no net effect in setting, but puts in a GSUB lookup (and table), just to see if it solves your problem.

You can read more about the Adobe feature file syntax specification at http://www.adobe.com/devnet/opentype/afdko/topic_feature_file_syntax.html

Seb McLauchlan

@Kent

Thanks for that, I've appended my feature file but am still coming across the same problem. My kerning is showing in InDesign but not in any other program, including all browsers. Do you have any idea why this might be the case?

Kent Lew

What other applications are you testing in? Is kerning displaying properly in the other Adobe apps?

In my experience, TextEdit support for kerning is buggy. I’ve got plenty of perfectly valid fonts installed whose kerning TextEdit will not display. I haven’t bothered to investigate where its idiosyncrasies stem from. But I run an older system and haven’t trialed the latest.

MS Word has kerning off by default and it needs to be explicitly activated. So if you’re reviewing in Word, be sure to do so.

Browsers are their own species of beast. I believe kerning may need to be explicitly invoked in your css, and each browser may take a different parameter to do so. But that’s not my area of focus, so someone else will have to point you in the right direction.

Seb McLauchlan

Hi Ken,

Yes the kerning is fine in Adobe apps, but every other program, whether Pages, Word or any other Non-Adobe text editor. This is very strange...

I've researched kerning in browser, and I have the necessary CSS to activate it, but it's just not loading for some reason.

Argh.. this is so frustrating.

Mark Simonson

Have you tried clearing the font caches?

Seb McLauchlan

@Mark
Yes just cleared them again and retried w/ test installation. No change in non-Adobe programs...

Seb McLauchlan

Ok.

Just took a look at my fdk components like @Marcos suggested. And I've noticed that even though I've deleted my KERN feature in this font and instead saved my kerning directly into the UFO as a .plist file like Ken suggested, it's still being generated in the FDK features file?

Any idea why this is happening? Sorry for seeming so clueless about this guys!

Seb McLauchlan

Heres a screenshot, hopefully this explains the situation better. TextEdit window on the right is the features file generated in the FDK folder.

Kent Lew

it's still being generated in the FDK features file?

Yes, this is what it is supposed to do. Robofont writes it from the kerning.plist data at the time of generation. That way you don’t have to maintain the data in two places and risk them becoming unsynchronized.

I have to say, those are some unusual kerning classes you have there — unless you’re using hacked character slots for nonstandard glyphs (which is frowned upon these days).

But that should not have any bearing on the problem you describe.

Wait . . . I just noticed that your language definition has only a latn/dflt declaration. You need to also declare languagesystem DFLT dflt; first.

For more about this, see the spec: http://www.adobe.com/devnet/opentype/afdko/topic_feature_file_syntax.html#4.b.i

“This script/language pair is special: it is used if a program cannot find a match in the font to the current writing script and language. If it is not in your font, then all the rules may be invisible to the program if your font does not have a match for the current script and language.”

This absence could be why other apps are not applying your kerning tables.

Seb McLauchlan

Still not working unfortunately @Kent



I seem to remember that a while ago when I created some test kerning pairs inside Robofont, without using MetricsMachine, the kerning was exported properly and was visible. So maybe the issue is with how MM is formatting the kerning?

Mark Simonson

Maybe try asking at the Robofont forum: http://doc.robofont.com/forums/

FWIW, use of Metrics Machine is very common among Robofont users, and integration is very tight. It seems unlikely that MM is the issue and I've never heard of anyone having the kind of trouble you're having with it. Not saying it couldn't be the problem, but it seems unlikely.

Seb McLauchlan

Hey @Kent finally got around to generating a TTX file from the .otf

What should I be looking for? I've opened it in TextEdit and quickly search for 'kern' and found two empty feature tags.

Kent Lew

Reading a TTX dump in TextEdit could get overwhelming. If you can, use a text editor that allows folding of the XML.

If the kerning exported correctly, then you should have a <GPOS> table, within which are a <ScriptList>, a <FeatureList>, and a <LookupList>.

In the <FeatureList>, I’m guessing you should find two <FeatureRecord>s, one for each of your languagesystem definitions, both with <FeatureTag value="kern"/>, and both should reference a <LookupListIndex>.

And then in your <LookupList>, you should find at least one <Lookup> and that/those should contain at least one <PairPos> that should in turn contain a <Coverage> list and a whole bunch of <PairSet> entries for kerning partners and values.

If it looks like this stuff is all present, then the font has some kerning info in it. The main point earlier when I mentioned a TTX dump was just to confirm that there is in fact a GPOS table with a {kern} FeatureRecord in it. Rummaging through the XML is probably not the place to do further troubleshooting, except as a last resort.

If the font was in fact generated with kerning, then I don’t know what else to tell you, in terms of the issues you’re experiencing with other apps. Not without getting hands-on and hands dirty with the font and source, which I’m afraid I don’t have to time to offer right now.

Yeah, it’s frustrating. But remember, you’re not just designing some nice letters, you’re building software.

Seb McLauchlan

Thanks for guiding me through that Kent, think we're finally getting somewhere.

Everything you mentioned is visible, except for the PairSet entries.

This is really strange then considering that the kerning is working in some programs, like the Adobe Suite.

Jackson Showalter-Cavanaugh

This shouldn't be so difficult. Have you tried rebuilding the font?

Seb McLauchlan

@Jackson
Could you explain the correct way to do that? Sorry if a lot of this seems obvious to you guys, but I'm learning much of this as I go.

Jackson Showalter-Cavanaugh

Open a new file and start copying/redoing things piece by piece. It's possible there is a tiny error in your groups or naming or ufo structure. Sometimes it's just easier to start from scratch, copying over glyphs, naming, ot features, and reimporting kerning one at a time and testing as you go.

Jason Campbell

Is the "kerning" you're seeing in the Adobe apps optical kerning?

Kent Lew

I had been wondering the same thing, Jason.