Bug 187774 – Use a single tri-state member to distinguish between "normal", "italic" and "oblique" font-style values

• Status: RESOLVED
• Resolution: FIXED
• Component: CSS

[Antoine Quint]

As part of https://bugs.webkit.org/show_bug.cgi?id=187722, we've made the FontDescriptionRequest slope member an optional to be able to distinguish between "normal" and any other value. However, we also need to look at the FontDescription fontStyleAxis member to distinguish between "italic" and "oblique 20deg". We should have a single tri-state member to distinguish between all these values.

[Radar WebKit Bug Importer]

<rdar://problem/172702768>

[Brent Fulgham]

This is more than just an architectural improvement: The lack of a tri-state representation led to incorrect font selection, where an attempt to select an oblique font would often improperly select an italic face, even when a normal face was available. CSS Fonts 4 explicitly states oblique should fall back to normal, and only use italic as a last result. We would often bypass normal and go to italic.

[Brent Fulgham]

Pull request: https://github.com/WebKit/WebKit/pull/60787

[EWS]

Committed 310249@main (b927d5607bfe): <https://commits.webkit.org/310249@main>

Reviewed commits have been landed. Closing PR #60787 and removing active labels.