CSS fallback for OpenType small caps

Question

I'm working on a site where small caps are important: setting the text of the Bible. In the Old Testament the name of God is transliterated as Lord but in small caps—not LORD. However, the state of OpenType small caps support at the moment is… less than optimal. Safari (even up through Safari 8 on Yosemite, from which I am typing this) still doesn't support the -webkit-font-feature-settings: 'smcp' option, and a lot of the hits for this website will be coming from mobile.

Unfortunately, "graceful degradation" is problematic here: if you specify both font-variant: small-caps and font-feature-settings: 'smcp' in a browser that supports the latter (e.g. Chrome), the font-variant declaration overrides it, so the horribly ugly old-style version still comes into play. (Note: this is as it should be per the spec: the font-variant declaration has a higher priority than the font-feature-settings declaration). Given the current implementations of font-variant: small-caps, though—shrunken capitals rather than actual small capitals—the result is that using font-variant: small-caps realists in not-so-gracefully degrading everyone's reading experience.

In the past, I have exported the small caps as a distinct webfont and specified them directly; see this post for a simple example: the first line of each paragraph is specified that way.

While I can do the same thing here (and at least in theory could deliver a pretty small typeface, since I really only need three characters: o, r, and d), I'd prefer simply to enable sane fallbacks. As noted above, however, that's not possible. I am open to but would very much prefer to avoid server-side solutions (browser detection, etc.) as a point of complexity that is better to minimize, especially given how rapidly browsers change. How else might one solve this problem, and especially are there existing solutions for it?

Edit: clarifying based on comments—in the future, font-variant: small-caps will handle this nicely, as per the spec it should display a small-capitals-variant of the typeface if the typeface supplies it. However, at present, no browser supports this (at least, none that I can find!). This means that instead, they all render fake small capitals simply by scaling down actual capitals. The result is typographically unpleasant, and unacceptable on this project.

Answer 1

Last updated 2016/02/28.

I spent a considerable amount of time researching this and wrestling with it. After digging around as best I could, the top solutions for now are:

@supports

Take advantage of the @supports rule in browsers. This is what I initially opted to do on this project.[1] You use the rule this way:

.some-class {
    font-variant: small-caps;
}

@supports(font-feature-settings: 'smcp') {
    .some-class {
        font-variant: normal;
        font-feature-settings: 'smcp';
    }
}

I've simplified by leaving out the prefixed versions; you'll need to add the -webkit- and -moz- prefixes to get this actually working. Update, 2012/02/28: you no longer need the -moz- prefix, and this will work in Safari in the next release (iOS 9.3 and OS X Safari 9.1).

This has the advantage that support for real small caps and support for the @supports rule are very similar:

• @supports: Can I Use Feature Queries?: Chrome 31+, Firefox 29+, Opera 23+, Android 4.4+, Safari 9+, Edge 12+, Chrome for Android

  Update, 2016/02/28: as the chart linked above will make clear, all evergreen browsers now have @supports support.

• font-feature-settings: Using Small Caps & Text Figures on the Web: Chrome, Firefox, IE10+

This isn't perfect: since IE10/11 don't implement @supports, you miss one browser. (Edit, 2015/09/31: IE proper doesn't have @supports, but Edge 12+ does, and that should increasingly cover all consumer users of the site.) Still, this gets you most of the way there, and it should be future-facing: this should progressively enhance the site nicely. The normal (bad, but functional) small caps are displayed in the meantime, and when browsers eventually get around to using OpenType small caps by default for font-variant: small-caps, this will continue to work just fine. It's "progressive enhancement" and it'll work nicely for most purposes.[2]

Typeface subsetting

As mentioned in the question, one can create a subset of the typeface that includes only small capitals. This is what I have done for the small caps on my own website; see the first line of the first paragraph in this post for an example.

To pull this off, you'll need to start by subsetting the typeface. You can do this manually with a font tool, or (the simpler way) you can use FontSquirrel's custom subsetting tool in their webfont generator. (Note: You must check the license and confirm that the typeface in question allows this kind of modification. See below.) In the web font generator, first upload the file you wish to modify. Then choose the Expert radio button. Most of the settings you can leave as they are; they're good sane defaults. Midway down the page you'll see OpenType Flattening options. Here, select only "Small Caps". Run the generator. The result will be a complete replacement of the normal lowercase letters with the small caps set.[3]

In that case, you can simply apply a style to the elements you want to have small capitals, e.g.:

.divine-name {
    font-family: 'my_typeface_smcp', 'my_typeface', serif;
}

The major advantage to this approach is consistency: that typeface is going to display on every browser out there, back to IE5.5, as long as you deliver it correctly using the various hooks required by @font-face.

There are a few disadvantages to this approach, though:

1. It means delivering another font file. In my case, this would be an acceeptably low size (since I actually only need four characters), but it's still something to consider in general. It is in any case another HTTP request, which is going to further slow the page load time or at least give you some flash of unstyled text when it reloads.

2. It may violate the licenses of the typefaces in question. For at least one of the fonts I am using on this project, it does: the license explicitly forbids rebuilding the font using tools like FontSquirrel. (FontSquirrel was the tool I used for this approach before, and it works quite well.) This is a make-or-break issue for using a subset of a typeface to accomplish the goal. That being said, if you have a good reason to do it, you may be able to get support from the vendor (especially if they're a small shop). For the project that prompted this question, I was able to do just that with a nice email—the designer is a great guy.

The other major reason not to do it this way is that it has a significantly higher maintenance cost. If at any point you need to change or update the typeface, you have to go through the subsetting process all over again. By contrast, the first option will simply work, though admittedly not as pleasantly as one might hope, and will not only continue to work but will actually improve over time as browsers increase their implementation of the CSS3 standard.

---

Notes

1. For various reasons (especially see note 2 below), I actually opted for the second approach outlined here, which is the same approach I was trying to avoid. Alas.

2. Issues remain: even in the latest Chrome (38 as of the time of this edit), using the font-feature-settings: 'smcp' approach has some issues. For example, if you turn on letter-spacing (a fairly common recommendation for small caps), the small caps will revert to normal lowercase letters. Fixed in Chrome 48. HT to answerer below.

3. From the FontSquirrel blog post that introduced the feature:

   If you have a font with OpenType features, you can now flatten some of them into your webfont. For instance, some fonts have small caps built in, but they are completely inaccessible in a web browser. By selecting the "Small Cap" option, the Generator will replace all the lowercase glyphs with the small cap variants, giving you a small cap font. Please note that not all OpenType features are supported and if the font lacks OpenType features, using these options won't create them.

Answer 2

Support for font-feature-settings:"smcp" has improved in recent browsers. Chrome 48 fixes the letter-spacing bug. And according to caniuse.com, upcoming versions of Safari for both iOS and Desktop will support it. The prefixed version is still required for -webkit, though.