Add linear animation curve

niri-config/src/lib.rs

@@ -657,6 +657,7 @@ pub struct EasingParams {
 
 #[derive(knuffel::DecodeScalar, Debug, Clone, Copy, PartialEq)]
 pub enum AnimationCurve {
+    Linear,
     EaseOutQuad,
     EaseOutCubic,
     EaseOutExpo,

src/animation/mod.rs

@@ -41,6 +41,7 @@ enum Kind {
 
 #[derive(Debug, Clone, Copy)]
 pub enum Curve {
+    Linear,
     EaseOutQuad,
     EaseOutCubic,
     EaseOutExpo,
@@ -358,6 +359,7 @@ impl Animation {
 impl Curve {
     pub fn y(self, x: f64) -> f64 {
         match self {
+            Curve::Linear => x,
             Curve::EaseOutQuad => EaseOutQuad.y(x),
             Curve::EaseOutCubic => EaseOutCubic.y(x),
             Curve::EaseOutExpo => 1. - 2f64.powf(-10. * x),
@@ -368,6 +370,7 @@ impl Curve {
 impl From<niri_config::AnimationCurve> for Curve {
     fn from(value: niri_config::AnimationCurve) -> Self {
         match value {
+            niri_config::AnimationCurve::Linear => Curve::Linear,
             niri_config::AnimationCurve::EaseOutQuad => Curve::EaseOutQuad,
             niri_config::AnimationCurve::EaseOutCubic => Curve::EaseOutCubic,
             niri_config::AnimationCurve::EaseOutExpo => Curve::EaseOutExpo,

wiki/Configuration:-Animations.md

@@ -71,11 +71,12 @@ animations {
 }
 ```
 
-Currently, niri only supports three curves:
+Currently, niri only supports four curves:
 
 - `ease-out-quad` <sup>Since: 0.1.5</sup>
 - `ease-out-cubic`
 - `ease-out-expo`
+- `linear` <sup>Since: 0.1.6</sup>
 
 You can get a feel for them on pages like [easings.net](https://easings.net/).