Intent to Prototype: linear() easing function

[David Shin]

Summary: `linear()` function (A new value for CSS `easing-functions`) lets authors specify custom easing functions as piecewise linear functions.

Bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1764126

Standard Draft: https://github.com/w3c/csswg-drafts/pull/6533

Standards Positions: https://github.com/mozilla/standards-positions/issues/649

Platform Coverage: all

Preference: layout.css.linear-easing-function.enabled

Other Browsers:

- Chrome: No signal, but spec author on Chrome team (Which is a reasonably strong sign of interest)

- Safari: No signal (https://bugs.webkit.org/show_bug.cgi?id=240061)

[Nicolas Chevobbe]

That’s a nice addition, thank you David.

I quickly checked what would be the impact on DevTools and it looks like we don’t show the function timing editor icon in the rule view when using `linear()`, so I filed https://bugzilla.mozilla.org/show_bug.cgi?id=1776382

We should probably think of what is the impact on the editor itself, as it only handles bezier curves at the moment. Is there anything we should take into consideration for this?
The good news is that the animation “curve” seems to be displayed properly in the animation panel.

Are you aware of any other possible impacts on DevTools, anything that could potentially break DevTools that we should know about in advance, so we have time to fix it?

[David Shin]

Ah, https://bugzilla.mozilla.org/show_bug.cgi?id=1773549 was filed for devtools work and it corroborates what you mentioned.

I've exercised the inspector and filed https://bugzilla.mozilla.org/show_bug.cgi?id=1776422 and https://bugzilla.mozilla.org/show_bug.cgi?id=1776424.

[Nicolas Chevobbe]

Ah I missed that, thanks a lot for filing the bugs