Font subsetting in the CSS API removes glyphs present in the full font

[iamakulov]

Font subsetting in the CSS API removes glyphs present in the full font

[iamakulov]

One easy (but maybe not good enough?) workaround Google Fonts can take is to include the full font as the very first @font-face:

/* full font */
@font-face {
  font-family: 'Inter Tight';
  font-style: italic;
  font-weight: 100 900;
  font-display: swap;
  src: url(https://fonts.gstatic.com/s/intertight/v7/NGSnv5HMAFg6IuGlBNMjxJEL2VmU3NS7Z2mj6AiqWSRToK8EPg.woff2) format('woff2');
  /* Note: no unicode-range */
}
/* cyrillic-ext */
@font-face {
  font-family: 'Inter Tight';
  font-style: italic;
  font-weight: 100 900;
  font-display: swap;
  src: url(https://fonts.gstatic.com/s/intertight/v7/NGSyv5HMAFg6IuGlBNMjxLsCwadkREW-emmbxg.woff2) format('woff2');
  unicode-range: U+0460-052F, U+1C80-1C88, U+20B4, U+2DE0-2DFF, U+A640-A69F, U+FE2E-FE2F;
}
/* cyrillic */
@font-face {
  font-family: 'Inter Tight';
  font-style: italic;
  font-weight: 100 900;
  font-display: swap;
  src: url(https://fonts.gstatic.com/s/intertight/v7/NGSyv5HMAFg6IuGlBNMjxLsCwa5kREW-emmbxg.woff2) format('woff2');
  unicode-range: U+0301, U+0400-045F, U+0490-0491, U+04B0-04B1, U+2116;
}
/* ... */

Per the spec, the later @font-faces take the precedence over the earlier ones. So in this situation, the full font will only be downloaded if the page uses glyphs not present in the subsetted @font-faces.

[emmamarichal]

@rsheeter, do you have an explanation?

[rsheeter]

This, while suboptimal, is by design.

For context,

Adding a "whole font" final face with no unicode-range results in an absurdly high volume of downloads to fetch characters the font doesn't support, often downloading several unicode-range faces plus a duplicative and unused whole font.

Generating a subsetting scheme unique to the family would fix this but we have not currently implemented that.

https://www.w3.org/TR/IFT/ is meant to fix this once and for all. We chose to deprioritize improving the existing mechanism to focus on that. In retrospect our estimates for how fast we could ship IFT may have been optimistic.