The implementation of an extended API of text metrics started in 2014: https://groups.google.com/a/chromium.org/d/msg/blink-dev/SgofW_bQ3ps/jNYamQHplAMJ But was never shipped, and had multiple undefined values that were not addressed for years. The spec has now evolved and we intend to ship actualBoundingBoxLeft, actualBoundingBoxRight, actualBoundingBoxAscent and actualBoundingBoxDescent according to the current spec: https://html.spec.whatwg.org/multipage/canvas.html#textmetrics

Specification

Specification link


Specification being incubated in a Community Group

Status in Chromium

Blink>Canvas


Enabled by default (tracking bug)

Consensus & Standardization

After a feature ships in Chrome, the values listed here are not guaranteed to be up to date.

Owners

Comments

This is an important API that had a lot of requests from developers.

Last updated on 2021-03-12