1917125 - [css-easing-2] Linear easing function should no longer require at least two points

Status: NEW

(Core :: CSS Transitions and Animations, defect)

Description

[Mozilla Apprentice]

A resolution was made for csswg-drafts/#10580.

[css-easing-2] Linear easing function requires at least two points?

• RESOLVED: Allow linear() to have a single stop

Discussion.

Comment 1

[Daniel Holbert [:dholbert]]

dshin, maybe you'd like to take this linear() followup item for a recent csswg resolution?

I think the intent is that we should now accept values like

animation-timing-function: linear(0.5 50%)

...which should be equivalent to what we get from:

animation-timing-function: linear(0.5 50%, 0.5 50%)

Comment 2

[Sebastian Zartner [:sebo]]

This change, even when it's pretty small, should probably be mentioned at https://developer.mozilla.org/en-US/docs/Web/CSS/easing-function#linear_easing_function and a new entry be added to the compat data for easing functions.

Sebastian

Comment 3

[David Shin[:dshin]]

(In reply to Daniel Holbert [:dholbert] from comment #1)

I think the intent is that we should now accept values like

animation-timing-function: linear(0.5 50%)

...which should be equivalent to what we get from:

animation-timing-function: linear(0.5 50%, 0.5 50%)

For clarity: It'd be instead identical to linear(0.5 0%, 0.5 100%) i.e. A flat 0.5 output from 0% to 100% input range.
In fact, in case of a single stop, specifying any percentage/input progress value redundant - linear(0.5 <P>%) for all valid <P> values are equivalent to linear(0.5 0%, 0.5 100%).

... Though, linear(0.5) (And, presumably, linear(0.5 <P>%)) would serialize to linear(0.5) and not linear(0.5 0%, 0.5 100%), which linear(0.5 0% 100%) serializes to, as per this comment. Made a comment in spec change for clarification.

Comment 4

[David Shin[:dshin]]

Attachment: WIP: Bug 1917125: - Allow single stop linear() transition function. r=#style