Opentype font features

[DomesticExtremis]

I realise that 'font-feature-settings' is still not officially in CSS3, so it is unlikely to be supported in ePUB or even any device, but I'm somewhat confused about the layout tags.

There is a registry of various tags such as 'liga', 'dlig', 'hist' maintained here, but MS seem to be shy about defining what each tag must contain, only supplying examples fo what is typical. I appreciate they will vary depending on the script, but surely something called standard ligatures should contain a certain set for latin, and another set for other say greek, yadda yadda.

The only way I can figure out what ligatures and other layout features are supported is by digging through the font info in FontForge, which is not entirely straight forward.

For instance, the "IM FELL Great Primer PRO" font available here has 'liga','dlig' but no 'hist' to get the long s directly, it can only be had via 'ss01' style set, only then will the long s ligatures 'liga' in work.

I did find a funky web tool that lets you turn on/off certain of the tags here, but it only supports certain of the most common tags. Even so , the drag and drop bit works very well.

So my question is how does one find out quickly and easily what layout tags are available and what they contain for a given font?

[Jellby]

Originally Posted by DomesticExtremis

I appreciate they will vary depending on the script, but surely something called standard ligatures should contain a certain set for latin, and another set for other say greek, yadda yadda.

Ideally, yes. But different fonts have different needs, and different designers different tastes. For instance, Vollkorn provides both an alternate f and "fi"-like ligatures. By default "liga", the "fi" ligature is active, but "fj" uses the alternate f instead, and the "fj" is available in "dlig" (if I remember correctly). Other fonts may include "fj" in the standard ligatures, or move "fi" to the discretionary ones.

So my question is how does one find out quickly and easily what layout tags are available and what they contain for a given font?

Is FontForge's metrics window quick and easy enough?

[DomesticExtremis]

Originally Posted by Jellby

Is FontForge's metrics window quick and easy enough?

I was using Element|Font info and then digging around in the Lookups section.

The metrics menu doesn't seem to contain anything related to font features (other
than kerning).

ETA I'm not really expert in FontForge, I have no aim to design a font, just use one,
but it is the only software I have right now that tells me, however painstakingly,
what I want to know.

[DomesticExtremis]

otfinfo gives some data - at least it's quick:

[me@home ~]otfinfo -f IMFeGPrm29C.otf 
aalt    Access All Alternates
calt    Contextual Alternates
dlig    Discretionary Ligatures
hist    Historical Forms
kern    Kerning
liga    Standard Ligatures
salt    Stylistic Alternates
smcp    Small Capitals
ss01    Stylistic Set 1
ss02    Stylistic Set 2
ss03    Stylistic Set 3
ss04    Stylistic Set 4

[Doitsu]

Originally Posted by DomesticExtremis

So my question is how does one find out quickly and easily what layout tags are available and what they contain for a given font?

AFAIK, there's no easy way to find out what layout tags are available. However, if you have Microsoft Word 2010 (or Office Starter 2010) installed, you can test the display of the most frequently used layout tags via the Advanced tab of the Font dialog box.

[Jellby]

Originally Posted by DomesticExtremis

The metrics menu doesn't seem to contain anything related to font features (other than kerning).

Window -> Open new metrics window (or something similar)

Write something in the box, and then you should have a list of features you can enable/disable, and see the effect.

It does't tell you what each feature does, but it's a relatively quick way to know e.g. if there's any way to enable a "ct" ligature or a long s.

[DomesticExtremis]

OK thanks Jellby.
I notice there are slight discrepancies between oftinfo and what I can see in FontForge.

Anyhoo, I tried using 'font-feature-settings' as suggested by the web page above in an epub, needless to say it did
not have any effect on my Kobo Mini, though the same document and css
works well in Firefox.

I guess we'll just have to wait...

[Hitch]

Originally Posted by DomesticExtremis

I realise that 'font-feature-settings' is still not officially in CSS3, so it is unlikely to be supported in ePUB or even any device, but I'm somewhat confused about the layout tags.

There is a registry of various tags such as 'liga', 'dlig', 'hist' maintained here, but MS seem to be shy about defining what each tag must contain, only supplying examples fo what is typical. I appreciate they will vary depending on the script, but surely something called standard ligatures should contain a certain set for latin, and another set for other say greek, yadda yadda.

The only way I can figure out what ligatures and other layout features are supported is by digging through the font info in FontForge, which is not entirely straight forward.

For instance, the "IM FELL Great Primer PRO" font available here has 'liga','dlig' but no 'hist' to get the long s directly, it can only be had via 'ss01' style set, only then will the long s ligatures 'liga' in work.

I did find a funky web tool that lets you turn on/off certain of the tags here, but it only supports certain of the most common tags. Even so , the drag and drop bit works very well.

So my question is how does one find out quickly and easily what layout tags are available and what they contain for a given font?

I have Typograf, which is pretty cheap (I have the paid-for version) and it gives me kerning pairs for those fonts that have ligatures. I don't know if that helps. It also has individual letter kerning, for those fonts (usually foundry fonts, obviously) that have the information available in the fontset.

Hitch