coderef

Font metric overridesLimited availability

The ascent-override, descent-override, and line-gap-override descriptors adjust the display of a font declared in an @font-face statement. This can help make fallback fonts look the same size.

Not yet supported in all major browsers — check the table and provide a fallback.

Browser support

DesktopChrome
1–86Not supported
87+Supportedsince Nov 17, 2020
Current: 155
Edge
12–86Not supported
87+Supportedsince Nov 19, 2020
Current: 154
Firefox
1–88Not supported
89+Supportedsince Jun 1, 2021
Current: 157
Safari
✕Not supportedup to 27
Current: 27
MobileChrome Android
18–86Not supported
87+Supportedsince Nov 17, 2020
Current: 155
Firefox Android
4–88Not supported
89+Supportedsince Jun 1, 2021
Current: 157
Safari iOS
✕Not supportedup to 27
Current: 27

How to use

Not supported in Safari, Safari iOS. Use feature detection below and provide a fallback (or a polyfill) for those browsers.

Example

Full syntax and examples are on MDN: ascentOverride.

Feature detection

JS · check before using
if ("FontFace" in globalThis && "ascentOverride" in FontFace.prototype) {
  // FontFace.ascentOverride is available
}

Sub-features

Support for each part of the feature (6). The overall table above shows when the whole feature works.

Sub-featureChromeEdgeFirefoxSafariChrome AndroidFirefox AndroidSafari iOS
FontFace.ascentOverride878789✕8789✕
FontFace.descentOverride878789✕8789✕
FontFace.lineGapOverride878789✕8789✕
@font-face.ascent-override878789✕8789✕
@font-face.descent-override878789✕8789✕
@font-face.line-gap-override878789✕8789✕