21 files changed, 534 insertions, 433 deletions

diff --git a/niri-visual-tests/src/cases/gradient_angle.rs b/niri-visual-tests/src/cases/gradient_angle.rs
index 64c953c4..39a2e4ef 100644
--- a/niri-visual-tests/src/cases/gradient_angle.rs
+++ b/niri-visual-tests/src/cases/gradient_angle.rs
@@ -1,8 +1,6 @@
 use std::f32::consts::{FRAC_PI_2, PI};
-use std::sync::atomic::Ordering;
 use std::time::Duration;
 
-use niri::animation::ANIMATION_SLOWDOWN;
 use niri::render_helpers::border::BorderRenderElement;
 use niri_config::{Color, CornerRadius, GradientInterpolation};
 use smithay::backend::renderer::element::RenderElement;
@@ -31,20 +29,13 @@ impl TestCase for GradientAngle {
     }
 
     fn advance_animations(&mut self, current_time: Duration) {
-        let mut delta = if self.prev_time.is_zero() {
+        let delta = if self.prev_time.is_zero() {
             Duration::ZERO
         } else {
             current_time.saturating_sub(self.prev_time)
         };
         self.prev_time = current_time;
 
-        let slowdown = ANIMATION_SLOWDOWN.load(Ordering::SeqCst);
-        if slowdown == 0. {
-            delta = Duration::ZERO
-        } else {
-            delta = delta.div_f64(slowdown);
-        }
-
         self.angle += delta.as_secs_f32() * PI;
 
         if self.angle >= PI * 2. {
diff --git a/niri-visual-tests/src/cases/gradient_area.rs b/niri-visual-tests/src/cases/gradient_area.rs
index 2fa275f2..6f0cf4f3 100644
--- a/niri-visual-tests/src/cases/gradient_area.rs
+++ b/niri-visual-tests/src/cases/gradient_area.rs
@@ -1,8 +1,6 @@
 use std::f32::consts::{FRAC_PI_4, PI};
-use std::sync::atomic::Ordering;
 use std::time::Duration;
 
-use niri::animation::ANIMATION_SLOWDOWN;
 use niri::layout::focus_ring::FocusRing;
 use niri::render_helpers::border::BorderRenderElement;
 use niri_config::{Color, CornerRadius, FloatOrInt, GradientInterpolation};
@@ -43,20 +41,13 @@ impl TestCase for GradientArea {
     }
 
     fn advance_animations(&mut self, current_time: Duration) {
-        let mut delta = if self.prev_time.is_zero() {
+        let delta = if self.prev_time.is_zero() {
             Duration::ZERO
         } else {
             current_time.saturating_sub(self.prev_time)
         };
         self.prev_time = current_time;
 
-        let slowdown = ANIMATION_SLOWDOWN.load(Ordering::SeqCst);
-        if slowdown == 0. {
-            delta = Duration::ZERO
-        } else {
-            delta = delta.div_f64(slowdown);
-        }
-
         self.progress += delta.as_secs_f32() * PI;
 
         if self.progress >= PI * 2. {
diff --git a/niri-visual-tests/src/cases/layout.rs b/niri-visual-tests/src/cases/layout.rs
index f979debb..0dbe004d 100644
--- a/niri-visual-tests/src/cases/layout.rs
+++ b/niri-visual-tests/src/cases/layout.rs
@@ -69,7 +69,7 @@ impl Layout {
         let mut layout = niri::layout::Layout::with_options(clock.clone(), options);
         layout.add_output(output.clone());
 
-        let start_time = clock.now();
+        let start_time = clock.now_unadjusted();
 
         Self {
             output,
@@ -207,24 +207,25 @@ impl TestCase for Layout {
         self.layout.are_animations_ongoing(Some(&self.output)) || !self.steps.is_empty()
     }
 
-    fn advance_animations(&mut self, current_time: Duration) {
+    fn advance_animations(&mut self, _current_time: Duration) {
+        let now_unadjusted = self.clock.now_unadjusted();
         let run = self
             .steps
             .keys()
             .copied()
-            .filter(|delay| self.start_time + *delay <= current_time)
+            .filter(|delay| self.start_time + *delay <= now_unadjusted)
             .collect::<Vec<_>>();
         for delay in &run {
             let now = self.start_time + *delay;
-            self.clock.set_time_override(Some(now));
-            self.layout.advance_animations(now);
+            self.clock.set_unadjusted(now);
+            self.layout.advance_animations();
 
             let f = self.steps.remove(delay).unwrap();
             f(self);
         }
 
-        self.clock.set_time_override(None);
-        self.layout.advance_animations(current_time);
+        self.clock.set_unadjusted(now_unadjusted);
+        self.layout.advance_animations();
     }
 
     fn render(
diff --git a/niri-visual-tests/src/cases/tile.rs b/niri-visual-tests/src/cases/tile.rs
index e2637698..f50edf37 100644
--- a/niri-visual-tests/src/cases/tile.rs
+++ b/niri-visual-tests/src/cases/tile.rs
@@ -90,8 +90,8 @@ impl TestCase for Tile {
         self.tile.are_animations_ongoing()
     }
 
-    fn advance_animations(&mut self, current_time: Duration) {
-        self.tile.advance_animations(current_time);
+    fn advance_animations(&mut self, _current_time: Duration) {
+        self.tile.advance_animations();
     }
 
     fn render(
diff --git a/niri-visual-tests/src/main.rs b/niri-visual-tests/src/main.rs
index fa035c75..59563651 100644
--- a/niri-visual-tests/src/main.rs
+++ b/niri-visual-tests/src/main.rs
@@ -2,15 +2,11 @@
 extern crate tracing;
 
 use std::env;
-use std::sync::atomic::Ordering;
 
 use adw::prelude::{AdwApplicationWindowExt, NavigationPageExt};
 use cases::Args;
-use gtk::prelude::{
-    AdjustmentExt, ApplicationExt, ApplicationExtManual, BoxExt, GtkWindowExt, WidgetExt,
-};
+use gtk::prelude::{ApplicationExt, ApplicationExtManual, BoxExt, GtkWindowExt, WidgetExt};
 use gtk::{gdk, gio, glib};
-use niri::animation::ANIMATION_SLOWDOWN;
 use smithay_view::SmithayView;
 use tracing_subscriber::EnvFilter;
 
@@ -66,20 +62,23 @@ fn on_startup(_app: &adw::Application) {
 
 fn build_ui(app: &adw::Application) {
     let stack = gtk::Stack::new();
+    let anim_adjustment = gtk::Adjustment::new(1., 0., 10., 0.1, 0.5, 0.);
 
     struct S {
         stack: gtk::Stack,
+        anim_adjustment: gtk::Adjustment,
     }
 
     impl S {
         fn add<T: TestCase + 'static>(&self, make: impl Fn(Args) -> T + 'static, title: &str) {
-            let view = SmithayView::new(make);
+            let view = SmithayView::new(make, &self.anim_adjustment);
             self.stack.add_titled(&view, None, title);
         }
     }
 
     let s = S {
         stack: stack.clone(),
+        anim_adjustment: anim_adjustment.clone(),
     };
 
     s.add(Window::freeform, "Freeform Window");
@@ -133,9 +132,6 @@ fn build_ui(app: &adw::Application) {
 
     let content_headerbar = adw::HeaderBar::new();
 
-    let anim_adjustment = gtk::Adjustment::new(1., 0., 10., 0.1, 0.5, 0.);
-    anim_adjustment
-        .connect_value_changed(|adj| ANIMATION_SLOWDOWN.store(adj.value(), Ordering::SeqCst));
     let anim_scale = gtk::Scale::new(gtk::Orientation::Horizontal, Some(&anim_adjustment));
     anim_scale.set_hexpand(true);
 
diff --git a/niri-visual-tests/src/smithay_view.rs b/niri-visual-tests/src/smithay_view.rs
index 68c5d67d..416729f0 100644
--- a/niri-visual-tests/src/smithay_view.rs
+++ b/niri-visual-tests/src/smithay_view.rs
@@ -1,4 +1,5 @@
 use gtk::glib;
+use gtk::prelude::*;
 use gtk::subclass::prelude::*;
 use smithay::utils::Size;
 
@@ -7,13 +8,13 @@ use crate::cases::{Args, TestCase};
 mod imp {
     use std::cell::{Cell, OnceCell, RefCell};
     use std::ptr::null;
+    use std::time::Duration;
 
     use anyhow::{ensure, Context};
     use gtk::gdk;
     use gtk::prelude::*;
     use niri::animation::Clock;
     use niri::render_helpers::{resources, shaders};
-    use niri::utils::get_monotonic_time;
     use smithay::backend::egl::ffi::egl;
     use smithay::backend::egl::EGLContext;
     use smithay::backend::renderer::gles::GlesRenderer;
@@ -31,7 +32,7 @@ mod imp {
         renderer: RefCell<Option<Result<GlesRenderer, ()>>>,
         pub make_test_case: OnceCell<DynMakeTestCase>,
         test_case: RefCell<Option<Box<dyn TestCase>>>,
-        clock: RefCell<Clock>,
+        pub clock: RefCell<Clock>,
     }
 
     #[glib::object_subclass]
@@ -127,6 +128,10 @@ mod imp {
 
             let size = self.size.get();
 
+            let frame_clock = self.obj().frame_clock().unwrap();
+            let time = Duration::from_micros(frame_clock.frame_time() as u64);
+            self.clock.borrow_mut().set_unadjusted(time);
+
             // Create the test case if missing.
             let mut case = self.test_case.borrow_mut();
             let case = case.get_or_insert_with(|| {
@@ -138,7 +143,7 @@ mod imp {
                 make(args)
             });
 
-            case.advance_animations(get_monotonic_time());
+            case.advance_animations(self.clock.borrow_mut().now());
 
             let rect: Rectangle<i32, Physical> = Rectangle::from_loc_and_size((0, 0), size);
 
@@ -238,13 +243,33 @@ glib::wrapper! {
 }
 
 impl SmithayView {
-    pub fn new<T: TestCase + 'static>(make_test_case: impl Fn(Args) -> T + 'static) -> Self {
+    pub fn new<T: TestCase + 'static>(
+        make_test_case: impl Fn(Args) -> T + 'static,
+        anim_adjustment: &gtk::Adjustment,
+    ) -> Self {
         let obj: Self = glib::Object::builder().build();
 
         let make = move |args| Box::new(make_test_case(args)) as Box<dyn TestCase>;
         let make_test_case = Box::new(make) as _;
         let _ = obj.imp().make_test_case.set(make_test_case);
 
+        anim_adjustment.connect_value_changed({
+            let obj = obj.downgrade();
+            move |adj| {
+                if let Some(obj) = obj.upgrade() {
+                    let mut clock = obj.imp().clock.borrow_mut();
+                    let instantly = adj.value() == 0.0;
+                    let rate = if instantly {
+                        1.0
+                    } else {
+                        1.0 / adj.value().max(0.001)
+                    };
+                    clock.set_rate(rate);
+                    clock.set_complete_instantly(instantly);
+                }
+            }
+        });
+
         obj
     }
 }
diff --git a/src/animation/clock.rs b/src/animation/clock.rs
index 3cfa727b..30f8bd45 100644
--- a/src/animation/clock.rs
+++ b/src/animation/clock.rs
@@ -1,41 +1,202 @@
-use std::cell::Cell;
+use std::cell::RefCell;
 use std::rc::Rc;
 use std::time::Duration;
 
 use crate::utils::get_monotonic_time;
 
-/// Clock that can have its time value overridden.
+/// Shareable lazy clock that can change rate.
 ///
-/// Can be cloned to share the same clock.
+/// The clock will fetch the time once and then retain it until explicitly cleared with
+/// [`Clock::clear`].
 #[derive(Debug, Default, Clone)]
 pub struct Clock {
-    time_override: Rc<Cell<Option<Duration>>>,
+    inner: Rc<RefCell<AdjustableClock>>,
+}
+
+#[derive(Debug, Default)]
+struct LazyClock {
+    time: Option<Duration>,
+}
+
+/// Clock that can adjust its rate.
+#[derive(Debug)]
+struct AdjustableClock {
+    inner: LazyClock,
+    current_time: Duration,
+    last_seen_time: Duration,
+    rate: f64,
+    complete_instantly: bool,
 }
 
 impl Clock {
-    /// Creates a new [`Clock`] with time override in place.
-    pub fn with_override(time: Duration) -> Self {
+    /// Creates a new clock with the given time.
+    pub fn with_time(time: Duration) -> Self {
+        let clock = AdjustableClock::new(LazyClock::with_time(time));
         Self {
-            time_override: Rc::new(Cell::new(Some(time))),
+            inner: Rc::new(RefCell::new(clock)),
         }
     }
 
-    /// Sets the current time override.
-    pub fn set_time_override(&mut self, time: Option<Duration>) {
-        self.time_override.set(time);
+    /// Returns the current time.
+    pub fn now(&self) -> Duration {
+        self.inner.borrow_mut().now()
     }
 
-    /// Gets the current time.
-    #[inline]
-    pub fn now(&self) -> Duration {
-        self.time_override.get().unwrap_or_else(get_monotonic_time)
+    /// Returns the underlying time not adjusted for rate change.
+    pub fn now_unadjusted(&self) -> Duration {
+        self.inner.borrow_mut().inner.now()
+    }
+
+    /// Sets the unadjusted clock time.
+    pub fn set_unadjusted(&mut self, time: Duration) {
+        self.inner.borrow_mut().inner.set(time);
+    }
+
+    /// Clears the stored time so it's re-fetched again next.
+    pub fn clear(&mut self) {
+        self.inner.borrow_mut().inner.clear();
+    }
+
+    /// Gets the clock rate.
+    pub fn rate(&self) -> f64 {
+        self.inner.borrow().rate()
+    }
+
+    /// Sets the clock rate.
+    pub fn set_rate(&mut self, rate: f64) {
+        self.inner.borrow_mut().set_rate(rate);
+    }
+
+    /// Returns whether animations should complete instantly.
+    pub fn should_complete_instantly(&self) -> bool {
+        self.inner.borrow().should_complete_instantly()
+    }
+
+    /// Sets whether animations should complete instantly.
+    pub fn set_complete_instantly(&mut self, value: bool) {
+        self.inner.borrow_mut().set_complete_instantly(value);
     }
 }
 
 impl PartialEq for Clock {
     fn eq(&self, other: &Self) -> bool {
-        Rc::ptr_eq(&self.time_override, &other.time_override)
+        Rc::ptr_eq(&self.inner, &other.inner)
     }
 }
 
 impl Eq for Clock {}
+
+impl LazyClock {
+    pub fn with_time(time: Duration) -> Self {
+        Self { time: Some(time) }
+    }
+
+    pub fn clear(&mut self) {
+        self.time = None;
+    }
+
+    pub fn set(&mut self, time: Duration) {
+        self.time = Some(time);
+    }
+
+    pub fn now(&mut self) -> Duration {
+        *self.time.get_or_insert_with(get_monotonic_time)
+    }
+}
+
+impl AdjustableClock {
+    pub fn new(mut inner: LazyClock) -> Self {
+        let time = inner.now();
+        Self {
+            inner,
+            current_time: time,
+            last_seen_time: time,
+            rate: 1.,
+            complete_instantly: false,
+        }
+    }
+
+    pub fn rate(&self) -> f64 {
+        self.rate
+    }
+
+    pub fn set_rate(&mut self, rate: f64) {
+        self.rate = rate.clamp(0., 1000.);
+    }
+
+    pub fn should_complete_instantly(&self) -> bool {
+        self.complete_instantly
+    }
+
+    pub fn set_complete_instantly(&mut self, value: bool) {
+        self.complete_instantly = value;
+    }
+
+    pub fn now(&mut self) -> Duration {
+        let time = self.inner.now();
+
+        if self.last_seen_time == time {
+            return self.current_time;
+        }
+
+        if self.last_seen_time < time {
+            let delta = time - self.last_seen_time;
+            let delta = delta.mul_f64(self.rate);
+            self.current_time = self.current_time.saturating_add(delta);
+        } else {
+            let delta = self.last_seen_time - time;
+            let delta = delta.mul_f64(self.rate);
+            self.current_time = self.current_time.saturating_sub(delta);
+        }
+
+        self.last_seen_time = time;
+        self.current_time
+    }
+}
+
+impl Default for AdjustableClock {
+    fn default() -> Self {
+        Self::new(LazyClock::default())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn frozen_clock() {
+        let mut clock = Clock::with_time(Duration::ZERO);
+        assert_eq!(clock.now(), Duration::ZERO);
+
+        clock.set_unadjusted(Duration::from_millis(100));
+        assert_eq!(clock.now(), Duration::from_millis(100));
+
+        clock.set_unadjusted(Duration::from_millis(200));
+        assert_eq!(clock.now(), Duration::from_millis(200));
+    }
+
+    #[test]
+    fn rate_change() {
+        let mut clock = Clock::with_time(Duration::ZERO);
+        clock.set_rate(0.5);
+
+        clock.set_unadjusted(Duration::from_millis(100));
+        assert_eq!(clock.now_unadjusted(), Duration::from_millis(100));
+        assert_eq!(clock.now(), Duration::from_millis(50));
+
+        clock.set_unadjusted(Duration::from_millis(200));
+        assert_eq!(clock.now_unadjusted(), Duration::from_millis(200));
+        assert_eq!(clock.now(), Duration::from_millis(100));
+
+        clock.set_unadjusted(Duration::from_millis(150));
+        assert_eq!(clock.now_unadjusted(), Duration::from_millis(150));
+        assert_eq!(clock.now(), Duration::from_millis(75));
+
+        clock.set_rate(2.0);
+
+        clock.set_unadjusted(Duration::from_millis(250));
+        assert_eq!(clock.now_unadjusted(), Duration::from_millis(250));
+        assert_eq!(clock.now(), Duration::from_millis(275));
+    }
+}
diff --git a/src/animation/mod.rs b/src/animation/mod.rs
index 5efb0f16..50dfc195 100644
--- a/src/animation/mod.rs
+++ b/src/animation/mod.rs
@@ -2,7 +2,6 @@ use std::time::Duration;
 
 use keyframe::functions::{EaseOutCubic, EaseOutQuad};
 use keyframe::EasingFunction;
-use portable_atomic::{AtomicF64, Ordering};
 
 mod spring;
 pub use spring::{Spring, SpringParams};
@@ -10,8 +9,6 @@ pub use spring::{Spring, SpringParams};
 mod clock;
 pub use clock::Clock;
 
-pub static ANIMATION_SLOWDOWN: AtomicF64 = AtomicF64::new(1.);
-
 #[derive(Debug, Clone)]
 pub struct Animation {
     from: f64,
@@ -24,7 +21,7 @@ pub struct Animation {
     /// Best effort; not always exactly precise.
     clamped_duration: Duration,
     start_time: Duration,
-    current_time: Duration,
+    clock: Clock,
     kind: Kind,
 }
 
@@ -50,23 +47,16 @@ pub enum Curve {
 
 impl Animation {
     pub fn new(
-        current_time: Duration,
+        clock: Clock,
         from: f64,
         to: f64,
         initial_velocity: f64,
         config: niri_config::Animation,
     ) -> Self {
-        // Scale the velocity by slowdown to keep the touchpad gestures feeling right.
-        let initial_velocity = initial_velocity * ANIMATION_SLOWDOWN.load(Ordering::Relaxed);
+        // Scale the velocity by rate to keep the touchpad gestures feeling right.
+        let initial_velocity = initial_velocity / clock.rate().max(0.001);
 
-        let mut rv = Self::ease(
-            current_time,
-            from,
-            to,
-            initial_velocity,
-            0,
-            Curve::EaseOutCubic,
-        );
+        let mut rv = Self::ease(clock, from, to, initial_velocity, 0, Curve::EaseOutCubic);
         if config.off {
             rv.is_off = true;
             return rv;
@@ -85,7 +75,6 @@ impl Animation {
         }
 
         let start_time = self.start_time;
-        let current_time = self.current_time;
 
         match config.kind {
             niri_config::AnimationKind::Spring(p) => {
@@ -97,11 +86,11 @@ impl Animation {
                     initial_velocity: self.initial_velocity,
                     params,
                 };
-                *self = Self::spring(current_time, spring);
+                *self = Self::spring(self.clock.clone(), spring);
             }
             niri_config::AnimationKind::Easing(p) => {
                 *self = Self::ease(
-                    current_time,
+                    self.clock.clone(),
                     self.from,
                     self.to,
                     self.initial_velocity,
@@ -112,27 +101,20 @@ impl Animation {
         }
 
         self.start_time = start_time;
-        self.current_time = current_time;
     }
 
     /// Restarts the animation using the previous config.
-    pub fn restarted(
-        &self,
-        current_time: Duration,
-        from: f64,
-        to: f64,
-        initial_velocity: f64,
-    ) -> Self {
+    pub fn restarted(&self, from: f64, to: f64, initial_velocity: f64) -> Self {
         if self.is_off {
             return self.clone();
         }
 
-        // Scale the velocity by slowdown to keep the touchpad gestures feeling right.
-        let initial_velocity = initial_velocity * ANIMATION_SLOWDOWN.load(Ordering::Relaxed);
+        // Scale the velocity by rate to keep the touchpad gestures feeling right.
+        let initial_velocity = initial_velocity / self.clock.rate().max(0.001);
 
         match self.kind {
             Kind::Easing { curve } => Self::ease(
-                current_time,
+                self.clock.clone(),
                 from,
                 to,
                 initial_velocity,
@@ -146,7 +128,7 @@ impl Animation {
                     initial_velocity: self.initial_velocity,
                     params: spring.params,
                 };
-                Self::spring(current_time, spring)
+                Self::spring(self.clock.clone(), spring)
             }
             Kind::Deceleration {
                 initial_velocity,
@@ -154,7 +136,7 @@ impl Animation {
             } => {
                 let threshold = 0.001; // FIXME
                 Self::decelerate(
-                    current_time,
+                    self.clock.clone(),
                     from,
                     initial_velocity,
                     deceleration_rate,
@@ -165,7 +147,7 @@ impl Animation {
     }
 
     pub fn ease(
-        current_time: Duration,
+        clock: Clock,
         from: f64,
         to: f64,
         initial_velocity: f64,
@@ -183,13 +165,13 @@ impl Animation {
             duration,
             // Our current curves never overshoot.
             clamped_duration: duration,
-            start_time: current_time,
-            current_time,
+            start_time: clock.now(),
+            clock,
             kind,
         }
     }
 
-    pub fn spring(current_time: Duration, spring: Spring) -> Self {
+    pub fn spring(clock: Clock, spring: Spring) -> Self {
         let _span = tracy_client::span!("Animation::spring");
 
         let duration = spring.duration();
@@ -203,14 +185,14 @@ impl Animation {
             is_off: false,
             duration,
             clamped_duration,
-            start_time: current_time,
-            current_time,
+            start_time: clock.now(),
+            clock,
             kind,
         }
     }
 
     pub fn decelerate(
-        current_time: Duration,
+        clock: Clock,
         from: f64,
         initial_velocity: f64,
         deceleration_rate: f64,
@@ -238,77 +220,26 @@ impl Animation {
             is_off: false,
             duration,
             clamped_duration: duration,
-            start_time: current_time,
-            current_time,
+            start_time: clock.now(),
+            clock,
             kind,
         }
     }
 
-    pub fn set_current_time(&mut self, time: Duration) {
-        if self.duration.is_zero() {
-            self.current_time = time;
-            return;
-        }
-
-        let end_time = self.start_time + self.duration;
-        if end_time <= self.current_time {
-            return;
-        }
-
-        let slowdown = ANIMATION_SLOWDOWN.load(Ordering::Relaxed);
-        if slowdown <= f64::EPSILON {
-            // Zero slowdown will cause the animation to end right away.
-            self.current_time = end_time;
-            return;
-        }
-
-        // We can't change current_time (since the incoming time values are always real-time), so
-        // apply the slowdown by shifting the start time to compensate.
-        if self.current_time <= time {
-            let delta = time - self.current_time;
-
-            let max_delta = end_time - self.current_time;
-            let min_slowdown = delta.as_secs_f64() / max_delta.as_secs_f64();
-            if slowdown <= min_slowdown {
-                // Our slowdown value will cause the animation to end right away.
-                self.current_time = end_time;
-                return;
-            }
-
-            let adjusted_delta = delta.div_f64(slowdown);
-            if adjusted_delta >= delta {
-                self.start_time -= adjusted_delta - delta;
-            } else {
-                self.start_time += delta - adjusted_delta;
-            }
-        } else {
-            let delta = self.current_time - time;
-
-            let min_slowdown = delta.as_secs_f64() / self.current_time.as_secs_f64();
-            if slowdown <= min_slowdown {
-                // Current time was about to jump to before the animation had started; let's just
-                // cancel the animation in this case.
-                self.current_time = end_time;
-                return;
-            }
-
-            let adjusted_delta = delta.div_f64(slowdown);
-            if adjusted_delta >= delta {
-                self.start_time += adjusted_delta - delta;
-            } else {
-                self.start_time -= delta - adjusted_delta;
-            }
+    pub fn is_done(&self) -> bool {
+        if self.clock.should_complete_instantly() {
+            return true;
         }
 
-        self.current_time = time;
-    }
-
-    pub fn is_done(&self) -> bool {
-        self.current_time >= self.start_time + self.duration
+        self.clock.now() >= self.start_time + self.duration
     }
 
     pub fn is_clamped_done(&self) -> bool {
-        self.current_time >= self.start_time + self.clamped_duration
+        if self.clock.should_complete_instantly() {
+            return true;
+        }
+
+        self.clock.now() >= self.start_time + self.clamped_duration
     }
 
     pub fn value(&self) -> f64 {
@@ -316,7 +247,7 @@ impl Animation {
             return self.to;
         }
 
-        let passed = self.current_time.saturating_sub(self.start_time);
+        let passed = self.clock.now().saturating_sub(self.start_time);
 
         match self.kind {
             Kind::Easing { curve } => {
diff --git a/src/input/mod.rs b/src/input/mod.rs
index eec8fbe4..bafa1505 100644
--- a/src/input/mod.rs
+++ b/src/input/mod.rs
@@ -83,11 +83,8 @@ impl State {
     {
         let _span = tracy_client::span!("process_input_event");
 
-        // A bit of a hack, but animation end runs some logic (i.e. workspace clean-up) and it
-        // doesn't always trigger due to damage, etc. So run it here right before it might prove
-        // important. Besides, animations affect the input, so it's best to have up-to-date values
-        // here.
-        self.niri.advance_animations(get_monotonic_time());
+        // Make sure some logic like workspace clean-up has a chance to run before doing actions.
+        self.niri.advance_animations();
 
         if self.niri.monitors_active {
             // Notify the idle-notifier of activity.
diff --git a/src/ipc/server.rs b/src/ipc/server.rs
index 16cc5524..facb59d3 100644
--- a/src/ipc/server.rs
+++ b/src/ipc/server.rs
@@ -314,6 +314,9 @@ async fn process(ctx: &ClientCtx, request: Request) -> Reply {
 
             let action = niri_config::Action::from(action);
             ctx.event_loop.insert_idle(move |state| {
+                // Make sure some logic like workspace clean-up has a chance to run before doing
+                // actions.
+                state.niri.advance_animations();
                 state.do_action(action, false);
                 let _ = tx.send_blocking(());
             });
diff --git a/src/layout/closing_window.rs b/src/layout/closing_window.rs
index 744c099e..12a77f92 100644
--- a/src/layout/closing_window.rs
+++ b/src/layout/closing_window.rs
@@ -1,5 +1,4 @@
 use std::collections::HashMap;
-use std::time::Duration;
 
 use anyhow::Context as _;
 use glam::{Mat3, Vec2};
@@ -138,15 +137,15 @@ impl ClosingWindow {
         })
     }
 
-    pub fn advance_animations(&mut self, current_time: Duration) {
+    pub fn advance_animations(&mut self) {
         match &mut self.anim_state {
             AnimationState::Waiting { blocker, anim } => {
                 if blocker.state() != BlockerState::Pending {
-                    let anim = anim.restarted(current_time, 0., 1., 0.);
+                    let anim = anim.restarted(0., 1., 0.);
                     self.anim_state = AnimationState::Animating(anim);
                 }
             }
-            AnimationState::Animating(anim) => anim.set_current_time(current_time),
+            AnimationState::Animating(_anim) => (),
         }
     }
 
diff --git a/src/layout/mod.rs b/src/layout/mod.rs
index f4e59af3..45228038 100644
--- a/src/layout/mod.rs
+++ b/src/layout/mod.rs
@@ -219,6 +219,8 @@ pub struct Layout<W: LayoutElement> {
     interactive_move: Option<InteractiveMoveState<W>>,
     /// Clock for driving animations.
     clock: Clock,
+    /// Time that we last updated render elements for.
+    update_render_elements_time: Duration,
     /// Configurable properties of the layout.
     options: Rc<Options>,
 }
@@ -447,6 +449,7 @@ impl<W: LayoutElement> Layout<W> {
             last_active_workspace_id: HashMap::new(),
             interactive_move: None,
             clock,
+            update_render_elements_time: Duration::ZERO,
             options: Rc::new(options),
         }
     }
@@ -468,6 +471,7 @@ impl<W: LayoutElement> Layout<W> {
             last_active_workspace_id: HashMap::new(),
             interactive_move: None,
             clock,
+            update_render_elements_time: Duration::ZERO,
             options: opts,
         }
     }
@@ -2194,22 +2198,22 @@ impl<W: LayoutElement> Layout<W> {
         }
     }
 
-    pub fn advance_animations(&mut self, current_time: Duration) {
+    pub fn advance_animations(&mut self) {
         let _span = tracy_client::span!("Layout::advance_animations");
 
         if let Some(InteractiveMoveState::Moving(move_)) = &mut self.interactive_move {
-            move_.tile.advance_animations(current_time);
+            move_.tile.advance_animations();
         }
 
         match &mut self.monitor_set {
             MonitorSet::Normal { monitors, .. } => {
                 for mon in monitors {
-                    mon.advance_animations(current_time);
+                    mon.advance_animations();
                 }
             }
             MonitorSet::NoOutputs { workspaces, .. } => {
                 for ws in workspaces {
-                    ws.advance_animations(current_time);
+                    ws.advance_animations();
                 }
             }
         }
@@ -2242,6 +2246,8 @@ impl<W: LayoutElement> Layout<W> {
     pub fn update_render_elements(&mut self, output: Option<&Output>) {
         let _span = tracy_client::span!("Layout::update_render_elements");
 
+        self.update_render_elements_time = self.clock.now();
+
         if let Some(InteractiveMoveState::Moving(move_)) = &mut self.interactive_move {
             if output.map_or(true, |output| move_.output == *output) {
                 let pos_within_output = move_.tile_render_location();
@@ -3475,6 +3481,10 @@ impl&