1814626 - Resolve line-height to used value in the style system

Status: RESOLVED FIXED

(Core :: CSS Parsing and Computation, enhancement)

Description

[Jonathan Kew [:jfkthame]]

Followup to bug 1813536, as Emilio noted in https://phabricator.services.mozilla.com/D168542#5545333:

we should be able to also clean-up nsComputedDOMStyle::DoGetLineHeight and co (since it's no longer layout-dependent with the exception of -moz-block-height, which is not exposed to content).

So we should be able to remove that code and this after this change, and it'd make longhands and shorthands return consistent values in the computed style.

An initial naïve attempt to do this ran into problems with html/rendering/non-replaced-elements/form-controls/input-line-height-computed.html, because (per Emilio in Matrix) "we implement this <input> line-height hack at used-value time".

This should also facilitate implementing the lh and rlh units.

Comment 1

[Emilio Cobos Álvarez (:emilio)]

Attachment: Bug 1814626 - Expose line-height resolution to style, and use it from ToResolvedValue. r=jfkthame

For ToResolvedValue implementation purposes we wouldn't need to split
out the vertical / font / line-height arguments and we could just pass
around the ComputedStyle, but the lh unit would need that distinction,
(because computing lh on font properties should use the parent style).

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/8de2aace34f0
Expose line-height resolution to style, and use it from ToResolvedValue. r=jfkthame

Comment 3

[Cristina Horotan [:chorotan]]

https://hg.mozilla.org/mozilla-central/rev/8de2aace34f0