[css-fonts-4] [varfont] Allow access to named instances outside of @font-face

[rsheeter]

#525 added access to named instances by specifying font-named-instance in @font-face.

For other aspects of a variable font you can specify on @font-face OR elsewhere. For example, font-variation-settings (https://drafts.csswg.org/css-fonts-4/#font-variation-settings-def) will let you use the font-face with different axis positions and font-display can be changed outside the @font-face with @font-feature-values (https://drafts.csswg.org/css-fonts-4/#font-display-font-feature-values).

Is it plausible that a mechanism be defined such that a font-named-instance be set outside of @font-face? Just allow font-named-instance in more places similar to font-variant-alternates?

For Google Fonts and other central services this would be very convenient: ask for a variable family and then access all sorts of fun parts of it. For example:

@import url('https://fonts.googleapis.com/css?family=Markazi+Text');

body { font-family: 'Markazi Text'; }

/* Here I can change axis positions (font-variation-settings) or set a font-display using @font-feature-settings but I can't change my axis positions using the named instances carefully defined by my type designer 😞 */
h1 { font-named-instance: 'Markazi Text Light'; }
h2 { font-named-instance: 'Markazi Text Bold'; }

[litherum]

Any solution for font-named-instance needs to work with fallback. Because of content blockers or network errors, the page author doesn't know exactly which font is being used on a particular element. font-named-instance was scoped to a particular @font-face block so it wouldn't apply across the entire font fallback list.

[svgeesus]

I agree with @litherum that this needs to be a descriptor tied to a specific @font-face for much the same reason that @font-feature-values is tied to a specific face (because stylistic sets are not portable between fonts and don't work correctly with fallback).

Also we need to retain the CSS model with independently-variable font-weight, font-style, font-stretch` etc within a family, rather than the "big list of font instances" model which does not allow for modification of an inherited font on a child element.

[rsheeter]

To give context, I'd love for all users of Markazi Text to share cache hits. If I have to modify the @font-face to produce a named instance then I have to either not support named instances in Google Fonts or add query params that bust the caching. Perhaps there is no realistic way to avoid this though?

[davelab6]

not support named instances in Google Fonts

I think this is fine; I think VF is a good opportunity to move designers away from using named styles and towards "relative typography" or "dynamic typography" with the advantages of "cascading" style sheets.

[rsheeter]

I don't disagree but I would prefer if our users had the option to easily use named instances as well :)