Imagine an upright design that relies heavily on precise spacing. As in, spaced really tight. A black design, a condensed design, doesn't matter. Now how do I go about designing an adequate italic companion? Obviously I will have plenty negative sidebearings which will one way or another collide when set immediately next to an upright glyph.
In practice, italic is set in isolation, so the most of an issue is collision with punctuation. Italic and upright in a single word happen mostly in logotypes and are kerned manually.
But I can imagine a discrete italic axis in a variable font so that the kerning can be included within the font. Has that been done?
As if the world needs something else to add to the degradation of typography -- as practiced by those with typographic knowledge, or as you refer to them, "nerds".
The existence of italic as a registered OT variation axis is a byproduct of the STAT table design. The STAT table is intended to replace the name table as the mechanism by which the relationships between members of a font family are defined, which is why the OT 1.8 spec not only introduced this table as a requirement for variable fonts but also recommended it for static fonts. The idea is that in future we won't need to keep adding new fields to the name table every time software makers come up with some new family model or font makers come up with new design relationships.
Some common aspects of conventional font family relationships, such as weight and width, can now be handled either in separate fonts or via variation axes, and in the STAT table these are identified as Axis Records, even if the STAT table is being used to define relationships between static font family members. It may be a little unintuitive, but the STAT table sort of applies the concepts of internal variable font relationships to non-variable fonts, so each static font is treated as if it were an instance of a variable font.
On this basis, the working group decided that it would be a good idea for every STAT table axis record tag to have a corresponding variable font axis, so in a WWS (weight, width, slope) family model as used by e.g. Microsoft's DWrite text library, not only the weight and width would have registered axes, but also the slope. Hence, the Italic and Slant axes.
I'm not sure anyone in the working group really expected anyone to use the Italic or Slant variation axes. If we had, we would probably have spent more time checking whether the trigonometry worked.
I'm having a hard time interpreting what you are trying to imply. All I meant was that the current implementation of italics is limiting, but it’s impossible to change that overnight. You did correctly decipher what I meant by “nerds”, though.
Years ago I was told that this feature is meant for CJK fonts only. Possibly it is time to rethink this unnecessary restriction.
So, I am not sure it is a “restriction”—but the existence of the feature is motivated by the history of how CJK fonts have been built.
Variations and STAT, for something as trivial as the requested functionality, is more than over the top.
I'd like to hear more about that.
(The font has an ital feature, which substitutes regular lowercase by italic lowercase, like o by o.it, but due to lack of support in applications I also added a stylistic set feature which does the same thing.)
It does within the MATH table, but not for general OT layout.
Maybe what we need is family kerning. Or maybe a universal kerning table that includes all existing fonts and sizes! I can hardly wait to build those billions of pairs.
I've mentioned this before, but I think the real solution is a spacing model that isn't based on simple advance width and therefore doesn't need kerning exceptions to get proper spacing. I don't expect it to happen (and I'm not even sure if it would work as well as I imagine), but that's my dream.
That would be another case of ‹using cannons to shoot sparrows› ...
To be fair to them (and you), the Chicago Manual of Style is certainly not gospel. Many editors choose to follow different style guides. There are plenty of others out there.
The idea to have an italic within a variable font, only makes sense, if there is any “variation” possible to derive such an italic from the corresponding upright.
For most fonts, especially serif fonts, this is not possible—because the italic is just a different design than the upright. It may be confusing to give the same family name to a different design—but this is just the convention.
To add an italic to those variable fonts in which it is possible to derive the italic from the corresponding upright, only creates confusion—when most variable fonts don’t have an italic included. (However, this does make sense in unusual fonts like Roslindale Variable Italic.)
So the idea to have an italic within a variable font, is a non-starter.