Implement Continuum compositor and shell motion

Cargo.lock

@@ -1675,6 +1675,7 @@ name = "ferese-animation"
 version = "0.1.0"
 dependencies = [
  "ferese-layout",
+ "serde",
 ]
 
 [[package]]
@@ -1784,6 +1785,7 @@ dependencies = [
 name = "ferese-shell"
 version = "0.1.0"
 dependencies = [
+ "ferese-animation",
  "ferese-config",
  "ferese-ipc",
  "ferese-protocols",

README.md

@@ -22,6 +22,7 @@ Ferese combines a window manager and desktop shell with one configuration.
 - Scrolling columns with window grouping, tree tiling and floating windows that remember their size and placement
 - Workspace overview and recent-window switching
 - Remappable keyboard shortcuts and touchpad gestures
+- [Continuum motion](docs/configuration.md#animations): interruptible springs, gesture momentum and motion settings shared by the compositor and shell
 - Multiple monitors with fractional scaling and automatic refresh-rate switching on low battery
 - Themes, wallpapers and blur that update live, with Light/Dark/Auto modes and custom KDL themes
 - Squircle window corners with matching borders and shadows
@@ -40,7 +41,7 @@ compares current upstream features and names separate tools where they are neede
 | Tiling layouts | Scrolling columns and tree tiling; switch per workspace | [Scrolling, dwindle, master and monocle; per-workspace layouts](https://github.com/hyprwm/Hyprland#features) | Scrolling columns |
 | Floating windows | Built in | Built in | Built in |
 | Workspace overview | Built in | Plugins such as [HyprExpo](https://github.com/sandwichfarm/hyprexpo) | Built in |
-| Animations | Spring and easing animations | Bézier and spring curves | [Spring and easing animations; custom shaders](https://niri-wm.github.io/niri/Configuration:-Animations.html) |
+| Animations | [Continuum: interruptible springs, gesture momentum; speed and reduced-motion settings shared by the compositor and shell](docs/configuration.md#animations) | Bézier and spring curves | [Spring and easing animations; custom shaders](https://niri-wm.github.io/niri/Configuration:-Animations.html) |
 | Live configuration reload | Yes | Yes | Yes |
 | Monitor mirroring | Built in | [Built in](https://wiki.hypr.land/configuring/core/monitors/) | Separate tool, such as [wl-mirror](https://niri-wm.github.io/niri/Screencasting.html#screen-mirroring) |
 | Desktop controls | Included Settings and Control Center | [Separate utilities](https://wiki.hypr.land/hypr-ecosystem/) or a desktop shell | [Separate desktop shell or tools](https://niri-wm.github.io/niri/Integrating-niri.html#desktop-components) |

compositor/src/backends/direct.rs

@@ -1058,17 +1058,6 @@ fn cursor_affected_outputs(state: &Ferese) -> Vec<Output> {
         .collect()
 }
 
-#[track_caller]
-pub(crate) fn render_window(state: &mut Ferese, window: ferese_layout::WindowId) {
-    let outputs = state
-        .space
-        .outputs()
-        .filter(|output| state.window_belongs_to_output(window, output))
-        .cloned()
-        .collect::<Vec<_>>();
-    render_on(state, &outputs);
-}
-
 #[track_caller]
 pub(crate) fn render_surface(
     state: &mut Ferese,

compositor/src/config.rs

@@ -346,34 +346,6 @@ const fn default_repeat_delay() -> i32 {
     600
 }
 
-const fn default_animation_speed() -> f64 {
-    1.0
-}
-
-const fn default_spring_mass() -> f64 {
-    1.0
-}
-
-const fn default_spring_stiffness() -> f64 {
-    700.0
-}
-
-const fn default_spring_damping() -> f64 {
-    53.0
-}
-
-const fn default_viewport_mass() -> f64 {
-    1.0
-}
-
-const fn default_viewport_stiffness() -> f64 {
-    320.0
-}
-
-const fn default_viewport_damping_ratio() -> f64 {
-    1.0
-}
-
 const fn default_true() -> bool {
     true
 }
@@ -384,6 +356,17 @@ pub(crate) fn config_path() -> Option<PathBuf> {
 
 #[cfg(test)]
 mod tests {
+    #[test]
+    fn rejects_undamped_overshoot_before_publication() {
+        for property in ["spring", "viewport-spring"] {
+            for coefficient in ["damping", "damping-ratio"] {
+                let source = format!("animations {{ {property} {{ {coefficient} 0; overshoot #true; }}; }}");
+                let error = Config::parse_source(&source).unwrap().runtime_config().err().unwrap().to_string();
+                assert!(error.contains("overshoot requires positive damping"), "{error}");
+            }
+        }
+    }
+
     use super::*;
 
     #[test]

compositor/src/config/input_motion.rs

@@ -44,7 +44,7 @@ impl Config {
     }
 
     pub fn animations_enabled(&self) -> bool {
-        self.animations.enabled && !self.animations.reduced_motion
+        self.animations.motion_enabled()
     }
 
     pub fn animation_speed(&self) -> Result<f64, ConfigError> {
@@ -52,39 +52,14 @@ impl Config {
     }
 
     pub fn spring_config(&self) -> Result<SpringConfig, ConfigError> {
-        let mass = positive_animation_value(self.animations.spring.mass, "spring.mass")?;
-        let stiffness = positive_animation_value(self.animations.spring.stiffness, "spring.stiffness")?;
-        let damping = self.animations.spring.damping;
-        if !damping.is_finite() || damping < 0.0 {
-            return Err(ConfigError::AnimationValue {
-                field: "spring.damping",
-                value: damping,
-            });
-        }
-
-        Ok(SpringConfig {
-            mass,
-            stiffness,
-            damping,
-            ..SpringConfig::default()
-        })
+        self.animations
+            .spring
+            .resolve(SpringConfig::default())
+            .map_err(ConfigError::Binding)
     }
 
     pub fn viewport_spring_config(&self) -> Result<SpringConfig, ConfigError> {
-        let mass = positive_animation_value(self.animations.viewport_spring.mass, "viewport_spring.mass")?;
-        let stiffness =
-            positive_animation_value(self.animations.viewport_spring.stiffness, "viewport_spring.stiffness")?;
-        let damping_ratio = positive_animation_value(
-            self.animations.viewport_spring.damping_ratio,
-            "viewport_spring.damping_ratio",
-        )?;
-
-        Ok(SpringConfig {
-            mass,
-            stiffness,
-            damping: 2.0 * damping_ratio * (stiffness * mass).sqrt(),
-            ..SpringConfig::default()
-        })
+        self.animations.viewport_config().map_err(ConfigError::Binding)
     }
 }
 
@@ -178,68 +153,4 @@ impl Default for TouchpadConfig {
     }
 }
 
-#[derive(Debug, Deserialize)]
-pub(super) struct AnimationsConfig {
-    #[serde(default = "enabled_by_default")]
-    pub(super) enabled: bool,
-    #[serde(default)]
-    pub(super) reduced_motion: bool,
-    #[serde(default = "default_animation_speed")]
-    pub(super) speed: f64,
-    #[serde(default)]
-    pub(super) spring: SpringSettings,
-    #[serde(default)]
-    pub(super) viewport_spring: ViewportSpringSettings,
-}
-
-impl Default for AnimationsConfig {
-    fn default() -> Self {
-        Self {
-            enabled: true,
-            reduced_motion: false,
-            speed: 1.0,
-            spring: SpringSettings::default(),
-            viewport_spring: ViewportSpringSettings::default(),
-        }
-    }
-}
-
-#[derive(Debug, Deserialize)]
-pub(super) struct ViewportSpringSettings {
-    #[serde(default = "default_viewport_mass")]
-    pub(super) mass: f64,
-    #[serde(default = "default_viewport_stiffness")]
-    pub(super) stiffness: f64,
-    #[serde(default = "default_viewport_damping_ratio")]
-    pub(super) damping_ratio: f64,
-}
-
-impl Default for ViewportSpringSettings {
-    fn default() -> Self {
-        Self {
-            mass: default_viewport_mass(),
-            stiffness: default_viewport_stiffness(),
-            damping_ratio: default_viewport_damping_ratio(),
-        }
-    }
-}
-
-#[derive(Debug, Deserialize)]
-pub(super) struct SpringSettings {
-    #[serde(default = "default_spring_mass")]
-    pub(super) mass: f64,
-    #[serde(default = "default_spring_stiffness")]
-    pub(super) stiffness: f64,
-    #[serde(default = "default_spring_damping")]
-    pub(super) damping: f64,
-}
-
-impl Default for SpringSettings {
-    fn default() -> Self {
-        Self {
-            mass: default_spring_mass(),
-            stiffness: default_spring_stiffness(),
-            damping: default_spring_damping(),
-        }
-    }
-}
+pub(super) type AnimationsConfig = ferese_animation::MotionSettings;

compositor/src/gestures.rs

@@ -1,5 +1,3 @@
-//! Navigation previews follow finger motion; actions commit once on release.
-
 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
 #[repr(u32)]
 pub(crate) enum SwipeDirection {
@@ -12,10 +10,16 @@ pub(crate) enum SwipeDirection {
 #[derive(Default)]
 pub(crate) struct Swipe {
     delta: Option<(f64, f64)>,
+    tracker_x: ferese_animation::gesture::VelocityTracker,
+    tracker_y: ferese_animation::gesture::VelocityTracker,
+    pub release_velocity: f64,
+    pub unbounded_release_velocity: f64,
+
     threshold: f64,
     fingers: u32,
     direction: Option<SwipeDirection>,
     preview_started: bool,
+    momentum_navigation: bool,
 }
 
 impl Swipe {
@@ -25,6 +29,59 @@ impl Swipe {
         self.fingers = fingers;
         self.direction = None;
         self.preview_started = false;
+        self.momentum_navigation = false;
+        self.tracker_x = Default::default();
+        self.tracker_y = Default::default();
+        self.release_velocity = 0.0;
+        self.unbounded_release_velocity = 0.0;
+    }
+
+    pub fn start_time(&mut self, time: std::time::Duration) {
+        self.tracker_x.push(time, 0.0);
+        self.tracker_y.push(time, 0.0);
+    }
+
+    pub fn update_at(&mut self, dx: f64, dy: f64, time: std::time::Duration) {
+        self.update(dx, dy);
+        if let Some((x, y)) = self.delta {
+            self.tracker_x.push(time, x);
+            self.tracker_y.push(time, y);
+        }
+    }
+
+    pub fn finish_at(&mut self, cancelled: bool, time: std::time::Duration) -> Option<SwipeDirection> {
+        let Some(direction) = self.direction else {
+            return self.finish(cancelled);
+        };
+        let v = match direction {
+            SwipeDirection::Left => -self.tracker_x.velocity(time),
+            SwipeDirection::Right => self.tracker_x.velocity(time),
+            SwipeDirection::Up => -self.tracker_y.velocity(time),
+            SwipeDirection::Down => self.tracker_y.velocity(time),
+        };
+        self.release_velocity = if cancelled {
+            0.0
+        } else {
+            v / (2.0 * self.threshold.max(1.0))
+        };
+        self.unbounded_release_velocity = self.release_velocity;
+        if !self.preview_started && !self.momentum_navigation {
+            return self.finish(cancelled);
+        }
+        let Some((_, progress)) = self.preview() else {
+            self.release_velocity = 0.0;
+            self.unbounded_release_velocity = 0.0;
+            self.delta = None;
+            return None;
+        };
+        // The preview is bounded. Its visible velocity is zero when pushing
+        // farther beyond either endpoint, even if the fingers keep moving.
+        if (progress == 0.0 && self.release_velocity < 0.0) || (progress == 1.0 && self.release_velocity > 0.0) {
+            self.release_velocity = 0.0;
+        }
+        self.delta = None;
+        (!cancelled && ferese_animation::gesture::project(progress, self.release_velocity, 0.997) >= 0.5)
+            .then_some(direction)
     }
 
     pub fn fingers(&self) -> u32 {
@@ -49,11 +106,20 @@ impl Swipe {
         self.preview_started = true;
     }
 
+    pub fn mark_momentum_navigation(&mut self) {
+        self.momentum_navigation = true;
+    }
+
     pub fn preview_started(&self) -> bool {
         self.preview_started
     }
 
     pub fn preview(&self) -> Option<(SwipeDirection, f64)> {
+        self.unbounded_preview()
+            .map(|(direction, progress)| (direction, progress.clamp(0.0, 1.0)))
+    }
+
+    pub fn unbounded_preview(&self) -> Option<(SwipeDirection, f64)> {
         let (x, y) = self.delta?;
         if !x.is_finite() || !y.is_finite() {
             return None;
@@ -65,7 +131,7 @@ impl Swipe {
             SwipeDirection::Up => -y,
             SwipeDirection::Down => y,
         };
-        Some((direction, (distance / (self.threshold.max(1.0) * 2.0)).clamp(0.0, 1.0)))
+        Some((direction, distance / (self.threshold.max(1.0) * 2.0)))
     }
 
     pub fn finish(&mut self, cancelled: bool) -> Option<SwipeDirection> {
@@ -103,6 +169,47 @@ fn dominant_direction(x: f64, y: f64, threshold: f64) -> Option<SwipeDirection>
 mod tests {
     use super::*;
 
+    #[test]
+    fn release_uses_momentum_and_a_pause_removes_it() {
+        use std::time::Duration;
+        let swipe = || {
+            let mut swipe = Swipe::default();
+            swipe.begin(3, false, 80);
+            swipe.start_time(Duration::ZERO);
+            swipe.update_at(0.0, -20.0, Duration::from_millis(10));
+            swipe.update_at(0.0, -20.0, Duration::from_millis(20));
+            swipe.mark_preview_started();
+            swipe
+        };
+        let mut flick = swipe();
+        assert_eq!(flick.preview(), Some((SwipeDirection::Up, 0.25)));
+        assert_eq!(
+            flick.finish_at(false, Duration::from_millis(20)),
+            Some(SwipeDirection::Up)
+        );
+        assert!((flick.release_velocity - 12.5).abs() < 1e-9);
+        let mut paused = swipe();
+        assert_eq!(paused.finish_at(false, Duration::from_millis(80)), None);
+        assert_eq!(paused.release_velocity, 0.0);
+        let mut cancelled = swipe();
+        assert_eq!(cancelled.finish_at(true, Duration::from_millis(20)), None);
+        assert_eq!(cancelled.release_velocity, 0.0);
+    }
+
+    #[test]
+    fn reversing_momentum_can_cancel_past_halfway() {
+        use std::time::Duration;
+        let mut swipe = Swipe::default();
+        swipe.begin(3, false, 80);
+        swipe.start_time(Duration::ZERO);
+        swipe.update_at(0.0, -120.0, Duration::from_millis(200));
+        swipe.update_at(0.0, 20.0, Duration::from_millis(210));
+        swipe.mark_preview_started();
+        assert_eq!(swipe.preview(), Some((SwipeDirection::Up, 0.625)));
+        assert_eq!(swipe.finish_at(false, Duration::from_millis(210)), None);
+        assert!(swipe.release_velocity < 0.0);
+    }
+
     #[test]
     fn cancellation_and_new_gestures_reset_preview_state() {
         let mut swipe = Swipe::default();

compositor/src/handlers/compositor.rs

@@ -37,6 +37,7 @@ impl CompositorHandler for Ferese {
     fn commit(&mut self, surface: &WlSurface) {
         self.update_surface_preferences(surface);
         self.capture_resize_before_commit(surface);
+        self.capture_close_before_commit(surface);
         on_commit_buffer_handler::<Self>(surface);
         if !is_sync_subsurface(surface) {
             let mut root = surface.clone();

compositor/src/input.rs

@@ -170,6 +170,7 @@ impl Ferese {
                             .any(|binding| binding.swipe_fingers(event.fingers())),
                     self.input_settings.touchpad.swipe_threshold,
                 );
+                self.swipe.start_time(std::time::Duration::from_micros(event.time()));
                 if self.swipe.active() {
                     self.focus_output_at(pointer.current_location());
                 } else {
@@ -185,7 +186,11 @@ impl Ferese {
             }
             InputEvent::GestureSwipeUpdate { event } => {
                 if self.swipe.active() {
-                    self.swipe.update(event.delta_x(), event.delta_y());
+                    self.swipe.update_at(
+                        event.delta_x(),
+                        event.delta_y(),
+                        std::time::Duration::from_micros(event.time()),
+                    );
                     if self.swipe_navigation_blocked() {
                         self.finish_workspace_swipe(None);
                         self.finish_focus_swipe(None);
@@ -198,10 +203,13 @@ impl Ferese {
                     {
                         match action {
                             BindingAction::SwitchRelativeWorkspace(next) => {
+                                self.swipe.mark_momentum_navigation();
                                 self.preview_workspace_swipe(next, direction, progress);
                             }
                             BindingAction::Focus(focus @ (Direction::Left | Direction::Right)) => {
-                                self.preview_focus_swipe(focus, direction, progress);
+                                self.swipe.mark_momentum_navigation();
+                                let raw = self.swipe.unbounded_preview().map_or(progress, |(_, value)| value);
+                                self.preview_focus_swipe(focus, direction, raw);
                             }
                             _ => {}
                         }
@@ -220,7 +228,9 @@ impl Ferese {
                 if self.swipe.active() {
                     let fingers = self.swipe.fingers();
                     let cancelled = event.cancelled() || self.swipe_navigation_blocked();
-                    let direction = self.swipe.finish(cancelled);
+                    let direction = self
+                        .swipe
+                        .finish_at(cancelled, std::time::Duration::from_micros(event.time()));
                     let workspace_handled = self.finish_workspace_swipe(direction);
                     let focus_handled = self.finish_focus_swipe(direction);
                     let handled = workspace_handled || focus_handled || self.swipe.preview_started();

compositor/src/overview.rs

@@ -17,7 +17,6 @@ const OVERVIEW_MARGIN: f64 = 48.0;
 const OVERVIEW_GAP: f64 = 40.0;
 // Applied after the configured animation speed, in both live and predicted motion.
 const OVERVIEW_MOTION_SPEED: f64 = 0.6;
-const EXIT_DURATION: f64 = 0.18;
 const WORKSPACE_CARD_GAP: f64 = 8.0;
 const MAX_PREVIEW_SCALE: f64 = 0.82;
 
@@ -117,7 +116,6 @@ pub(crate) struct OverviewMotion {
     active: bool,
     presentations: HashMap<WindowId, AnimatedRect>,
     opacity: AnimatedValue,
-    exit_transition: Option<(f64, f64)>,
 }
 
 impl Default for OverviewState {
@@ -179,8 +177,7 @@ fn centered_row_start(strip: Rect, count: usize, card_width: f64) -> f64 {
 
 impl OverviewState {
     pub(crate) fn needs_tick(&self) -> bool {
-        self.motion.exit_transition.is_some()
-            || self.motion.opacity.current != self.motion.opacity.target
+        self.motion.opacity.current != self.motion.opacity.target
             || self.motion.opacity.velocity != 0.0
             || self
                 .motion
@@ -366,25 +363,22 @@ impl OverviewState {
         self.motion.presented_rect(id, normal)
     }
 
+    pub(crate) fn presented_velocity(&self, id: WindowId) -> Option<ferese_animation::RectVelocity> {
+        let velocity = self.motion.presentations.get(&id)?.velocity;
+        Some(ferese_animation::RectVelocity {
+            x: velocity.x * OVERVIEW_MOTION_SPEED,
+            y: velocity.y * OVERVIEW_MOTION_SPEED,
+            width: velocity.width * OVERVIEW_MOTION_SPEED,
+            height: velocity.height * OVERVIEW_MOTION_SPEED,
+        })
+    }
+
     fn enter(
         &mut self,
         targets: HashMap<WindowId, (Rect, Rect)>,
         selected: Option<WindowId>,
         animations_enabled: bool,
     ) {
-        // Reverse a dismissal from the currently visible geometry, not the old grid.
-        if self.motion.exit_transition.is_some() {
-            let visible: Vec<_> = targets
-                .iter()
-                .map(|(id, (normal, _))| (*id, self.presented_rect(*id, *normal)))
-                .collect();
-            for (id, rect) in visible {
-                if let Some(presentation) = self.motion.presentations.get_mut(&id) {
-                    *presentation = AnimatedRect::new(rect);
-                }
-            }
-        }
-        self.motion.exit_transition = None;
         self.selection_workspace = None;
         self.motion.active = true;
         self.motion.opacity.retarget_preserving_motion(1.0);
@@ -423,7 +417,6 @@ impl OverviewState {
 
     fn exit(&mut self, normal: HashMap<WindowId, Rect>, animations_enabled: bool) {
         self.motion.active = false;
-        self.motion.exit_transition = animations_enabled.then_some((0.0, self.motion.opacity.current));
         self.motion.opacity.retarget_preserving_motion(0.0);
         if !animations_enabled {
             self.motion.opacity.snap();
@@ -605,6 +598,17 @@ impl Ferese {
 
     pub(crate) fn retarget_overview(&mut self) {
         if !self.overview.is_active() {
+            if self.overview.is_presenting() {
+                let normal = self.normal_window_rects();
+                self.overview.motion.presentations.retain(|id, presentation| {
+                    if let Some(target) = normal.get(id) {
+                        presentation.set_target(*target);
+                        true
+                    } else {
+                        false
+                    }
+                });
+            }
             return;
         }
 
@@ -643,17 +647,26 @@ impl Ferese {
             presented.x += x;
             presented.y += y;
         }
-        Some(presented)
+        let record = self.windows.record(id)?;
+        let opening = record.opening.map_or(1.0, |value| value.current);
+        Some(crate::presentation::scaled_visual_rect(
+            presented,
+            0.97 + 0.03 * opening,
+        ))
     }
 
     pub(crate) fn inverse_presented_window_point(&self, id: WindowId, x: f64, y: f64) -> Option<(f64, f64)> {
         let geometry = self.windows.geometry(&id)?;
-        if !self.overview.is_presenting() {
+        if !self.overview.is_presenting() && self.windows.record(id)?.opening.is_none() {
             let presented = self.presented_window_rect(id)?;
             return Some((x - presented.x, y - presented.y));
         }
-        let source = geometry.client.committed_size?;
-        let presented = self.overview.presented_rect(id, geometry.visual.current);
+        let source = if self.overview.is_presenting() {
+            geometry.client.committed_size?
+        } else {
+            ferese_animation::ClientSize::from_rect(geometry.visual.current)
+        };
+        let presented = self.presented_window_rect(id)?;
 
         if source.width <= 0 || source.height <= 0 || presented.width <= 0.0 || presented.height <= 0.0 {
             return None;
@@ -989,15 +1002,13 @@ impl Default for OverviewMotion {
             active: false,
             presentations: HashMap::new(),
             opacity: AnimatedValue::new(0.0),
-            exit_transition: None,
         }
     }
 }
 
 impl OverviewMotion {
     pub(crate) fn is_animating(&self, spring: SpringConfig) -> bool {
-        self.exit_transition.is_some()
-            || (self.opacity.current - self.opacity.target).abs() > 0.001
+        (self.opacity.current - self.opacity.target).abs() > 0.001
             || self.opacity.velocity.abs() > 0.005
             || self.presentations.values().any(|rect| !rect.is_settled(spring))
     }
@@ -1012,43 +1023,17 @@ impl OverviewMotion {
 
     pub(crate) fn presented_rect(&self, id: WindowId, normal: Rect) -> Rect {
         let preview = self.presentations.get(&id).map_or(normal, |p| p.current);
-        if let Some((elapsed, _)) = self.exit_transition {
-            let t = 1.0 - (1.0 - (elapsed / EXIT_DURATION).clamp(0.0, 1.0)).powi(3);
-            return Rect::new(
-                preview.x + (normal.x - preview.x) * t,
-                preview.y + (normal.y - preview.y) * t,
-                preview.width + (normal.width - preview.width) * t,
-                preview.height + (normal.height - preview.height) * t,
-            );
-        }
         preview
     }
 
     pub(crate) fn advance(&mut self, delta: Duration, spring: SpringConfig, animations_enabled: bool) -> bool {
         let delta = delta.mul_f64(OVERVIEW_MOTION_SPEED);
 
-        if let Some((elapsed, initial_opacity)) = self.exit_transition {
-            let elapsed = if animations_enabled {
-                elapsed + delta.as_secs_f64()
-            } else {
-                EXIT_DURATION
-            };
-            let remaining = (1.0 - elapsed / EXIT_DURATION).clamp(0.0, 1.0);
-            self.opacity.current = initial_opacity * remaining.powi(3);
-            if elapsed >= EXIT_DURATION {
-                self.exit_transition = None;
-                self.presentations.clear();
-                self.opacity.snap();
-                return false;
-            }
-            self.exit_transition = Some((elapsed, initial_opacity));
-            return true;
-        }
         let mut active_animation = false;
 
         for presentation in self.presentations.values_mut() {
             if animations_enabled {
-                active_animation |= presentation.advance_with_policy(delta, spring, CrossingPolicy::NoCrossing);
+                active_animation |= presentation.advance(delta, spring);
             } else {
                 presentation.snap();
             }
@@ -1197,7 +1182,7 @@ mod tests {
         let before = overview.presented_rect(id, normal);
         let opacity = overview.opacity();
 
-        let finished = overview.sample(Duration::from_millis(24), SpringConfig::default());
+        let finished = overview.sample(Duration::from_secs(2), SpringConfig::default());
         let earlier = overview.sample(Duration::from_millis(4), SpringConfig::default());
 
         assert!(!finished.is_presenting());
@@ -1351,7 +1336,7 @@ mod tests {
     }
 
     #[test]
-    fn exiting_overview_tracks_a_moving_layout_and_finishes_in_300ms() {
+    fn exiting_overview_retargets_without_resetting_motion() {
         let id = WindowId(1);
         let initial = Rect::new(-400.0, 0.0, 800.0, 600.0);
         let preview = Rect::new(100.0, 100.0, 400.0, 300.0);
@@ -1359,10 +1344,15 @@ mod tests {
         let mut overview = OverviewState::default();
         overview.enter(HashMap::from([(id, (initial, preview))]), Some(id), false);
         overview.exit(HashMap::from([(id, initial)]), true);
-        overview.advance(Duration::from_millis(150), SpringConfig::default(), true);
-        let shown = overview.presented_rect(id, moved);
-        assert!((shown.x - 187.5).abs() < 0.001);
-        overview.advance(Duration::from_millis(150), SpringConfig::default(), true);
+        overview.advance(Duration::from_millis(60), SpringConfig::default(), true);
+        let before = overview.motion.presentations[&id];
+        overview.exit(HashMap::from([(id, moved)]), true);
+        let after = overview.motion.presentations[&id];
+        assert_eq!(before.current, after.current);
+        assert_eq!(before.velocity, after.velocity);
+        for _ in 0..300 {
+            overview.advance(Duration::from_millis(8), SpringConfig::default(), true);
+        }
         assert!(!overview.is_presenting());
         assert_eq!(overview.presented_rect(id, moved), moved);
     }
@@ -1378,7 +1368,9 @@ mod tests {
         overview.exit(HashMap::from([(id, normal)]), true);
         overview.advance(Duration::from_millis(60), SpringConfig::default(), true);
         let shown = overview.presented_rect(id, normal);
+        let velocity = overview.motion.presentations[&id].velocity;
         overview.enter(targets, Some(id), true);
+        assert_eq!(overview.motion.presentations[&id].velocity, velocity);
         assert_eq!(overview.presented_rect(id, normal), shown);
     }
 

compositor/src/presentation.rs

@@ -523,3 +523,63 @@ mod tests {
         assert!(handoff_alpha(Duration::from_millis(1)) > 0.99);
     }
 }
+
+pub(crate) fn scaled_visual_rect(rect: ferese_layout::Rect, scale: f64) -> ferese_layout::Rect {
+    let scale = scale.max(0.0);
+    let width = rect.width * scale;
+    let height = rect.height * scale;
+
+    ferese_layout::Rect::new(
+        rect.x + (rect.width - width) / 2.0,
+        rect.y + (rect.height - height) / 2.0,
+        width,
+        height,
+    )
+}
+
+pub(crate) fn scaled_visual_velocity(
+    rect: ferese_layout::Rect,
+    velocity: ferese_animation::RectVelocity,
+    scale: f64,
+    scale_velocity: f64,
+) -> ferese_animation::RectVelocity {
+    ferese_animation::RectVelocity {
+        x: velocity.x + ((1.0 - scale) * velocity.width - rect.width * scale_velocity) * 0.5,
+        y: velocity.y + ((1.0 - scale) * velocity.height - rect.height * scale_velocity) * 0.5,
+        width: velocity.width * scale + rect.width * scale_velocity,
+        height: velocity.height * scale + rect.height * scale_velocity,
+    }
+}
+
+#[cfg(test)]
+mod motion_tests {
+    use super::*;
+    #[test]
+    fn center_scale_velocity_matches_the_visible_rectangle() {
+        let rect = ferese_layout::Rect::new(12.25, 18.75, 400.5, 300.25);
+        let velocity = ferese_animation::RectVelocity {
+            x: 80.0,
+            y: -40.0,
+            width: 100.0,
+            height: 20.0,
+        };
+        let v = scaled_visual_velocity(rect, velocity, 0.98, 0.07);
+        let before = scaled_visual_rect(rect, 0.98);
+        let dt = 1e-5;
+        let next = ferese_layout::Rect::new(
+            rect.x + velocity.x * dt,
+            rect.y + velocity.y * dt,
+            rect.width + velocity.width * dt,
+            rect.height + velocity.height * dt,
+        );
+        let after = scaled_visual_rect(next, 0.98 + 0.07 * dt);
+        for (measured, expected) in [
+            ((after.x - before.x) / dt, v.x),
+            ((after.y - before.y) / dt, v.y),
+            ((after.width - before.width) / dt, v.width),
+            ((after.height - before.height) / dt, v.height),
+        ] {
+            assert!((measured - expected).abs() < 0.0001);
+        }
+    }
+}

compositor/src/render/closing.rs

@@ -0,0 +1,191 @@
+use super::*;
+use ferese_animation::{AnimatedRect, AnimatedValue, CrossingPolicy, SpringConfig};
+use ferese_core::OutputId;
+use ferese_layout::WindowId;
+
+/// Detached presentation only: no live window, input, focus, or layout entry.
+#[derive(Clone)]
+pub(crate) struct ClosedWindow {
+    pub id: WindowId,
+    pub output: OutputId,
+    pub below: Option<WindowId>,
+    pub bounds: AnimatedRect,
+    pub opacity: AnimatedValue,
+    pub snapshot: ResizeSnapshot,
+    pub source: Rectangle<f64, Buffer>,
+    pub radius: f64,
+    pub shape: CornerShape,
+    pub focus: f64,
+    pub decorations: f64,
+    pub dim: f64,
+    pub fill: Option<[f32; 4]>,
+    pub material: Option<(
+        smithay::reexports::wayland_server::protocol::wl_surface::WlSurface,
+        crate::effects::SemanticRole,
+        u64,
+        f32,
+    )>,
+}
+
+impl ClosedWindow {
+    pub fn advance(&mut self, delta: Duration, spring: SpringConfig) -> bool {
+        self.bounds.advance(delta, spring);
+        let opacity = self.opacity.advance_with_policy(
+            delta,
+            SpringConfig {
+                position_tolerance: 0.001,
+                velocity_tolerance: 0.001,
+                ..spring
+            },
+            CrossingPolicy::NoCrossing,
+        );
+        self.snapshot.commit.increment();
+        // Once invisible there is no reason to keep a texture (including with
+        // intentionally undamped, overshooting geometry configurations).
+        opacity
+    }
+}
+
+pub(super) fn elements(
+    state: &mut Ferese,
+    renderer: &mut GlesRenderer,
+    output: &Output,
+    below: Option<WindowId>,
+    live: &std::collections::HashSet<WindowId>,
+    delta: Duration,
+) -> Vec<AnimatedWindowRenderElement> {
+    if state.session_lock.active() {
+        return Vec::new();
+    }
+    let Some(output_id) = state.output_id(output) else {
+        return Vec::new();
+    };
+    let Some(output_geometry) = state.space.output_geometry(output) else {
+        return Vec::new();
+    };
+    let scale = output.current_scale().fractional_scale();
+    let windows: Vec<_> = state
+        .render
+        .closing
+        .iter()
+        .filter(|window| {
+            window.output == output_id
+                && window.below.filter(|id| live.contains(id)) == below
+                && window.snapshot.context == renderer.context_id().erased()
+        })
+        .cloned()
+        .collect();
+    let mut elements = Vec::new();
+    for mut window in windows {
+        if !delta.is_zero() {
+            window.advance(delta, state.spring_config);
+        }
+        let visual = window.bounds.current;
+        let corners = RoundedRect::new(visual, output_geometry.loc, scale, window.radius).with_shape(window.shape);
+        let constrain = rounded_visual_rect(visual, output_geometry.loc);
+        let Some(programs) = corner_program(&mut state.render, renderer, window.shape) else {
+            continue;
+        };
+        let alpha = window.opacity.current.clamp(0.0, 1.0) as f32;
+        if let Some(dim) = window_tint_element(
+            &mut state.render,
+            renderer,
+            window.id,
+            constrain,
+            corners,
+            [0.0, 0.0, 0.0, window.dim as f32 * alpha],
+            false,
+            output,
+        ) {
+            elements.push(dim.into());
+        }
+        let theme = &state.theme_settings;
+        if let Some(border) = window_border_element(
+            &mut state.render,
+            theme,
+            renderer,
+            window.id,
+            constrain,
+            corners,
+            scale,
+            theme.border_width + (theme.focus_ring_width - theme.border_width) * window.focus,
+            theme.border_color.0,
+            theme.border_gradient,
+            window.focus as f32,
+            alpha * window.decorations as f32,
+            output,
+            &programs,
+        ) {
+            elements.push(border.into());
+        }
+        let clip = framebuffer_clip_rect(
+            corners.rect,
+            output.current_mode().unwrap().size,
+            output.current_transform().invert(),
+        );
+        elements.push(
+            NativeTextureElement {
+                id: window.snapshot.id.clone(),
+                commit: window.snapshot.commit,
+                texture: window.snapshot.texture.clone(),
+                geometry: corners.rect,
+                source: window.source,
+                alpha,
+                program: Some(programs.texture.clone()),
+                uniforms: vec![Uniform::new("clip_rect", clip), Uniform::new("radius", corners.radius)],
+            }
+            .into(),
+        );
+        if let Some(mut fill) = window.fill {
+            fill[3] = alpha;
+            if let Some(fill) = window_tint_element(
+                &mut state.render,
+                renderer,
+                window.id,
+                constrain,
+                corners,
+                fill,
+                true,
+                output,
+            ) {
+                elements.push(fill.into());
+            }
+        }
+        if let Some((surface, role, generation, opacity)) = &window.material {
+            if let Some((material, _)) = material_element_with_role(
+                state,
+                renderer,
+                output,
+                surface,
+                MaterialSurface {
+                    geometry: constrain,
+                    corners,
+                    index: 0,
+                    capture_geometry: constrain,
+                    alpha,
+                },
+                (*role, *generation, *opacity),
+            ) {
+                elements.push(material);
+            }
+        }
+        let theme = &state.theme_settings;
+        if let Some(shadow) = window_shadow_element(
+            &mut state.render,
+            renderer,
+            window.id,
+            constrain,
+            corners,
+            scale,
+            theme.shadow_offset_y,
+            theme.shadow_blur,
+            theme.shadow_opacity * f64::from(alpha) * window.decorations,
+            theme.shadow_color.0,
+            output,
+            &programs,
+        ) {
+            elements.push(shadow.into());
+        }
+    }
+    elements
+}

compositor/src/render/decorations.rs

@@ -380,6 +380,7 @@ pub(super) fn rounded_window_elements(
     output: &Output,
     programs: RoundedClipPrograms,
     behavior: ConstrainScaleBehavior,
+    native_size: Option<ferese_animation::ClientSize>,
 ) -> Vec<AnimatedWindowRenderElement> {
     let Some(toplevel) = window.toplevel() else {
         return Vec::new();
@@ -390,7 +391,13 @@ pub(super) fn rounded_window_elements(
 
     let physical_constrain = corners.rect;
     let geometry = window.geometry();
-    let reference = geometry.to_physical_precise_round(scale);
+    let mut reference = geometry.to_physical_precise_round(scale);
+    let behavior = if let Some(size) = native_size {
+        reference.size = Size::<i32, Logical>::from((size.width, size.height)).to_physical_precise_round(scale);
+        ConstrainScaleBehavior::Stretch
+    } else {
+        behavior
+    };
     let location = physical_constrain.loc - geometry.loc.to_physical_precise_round(scale);
     let clip = framebuffer_clip_rect(physical_constrain, mode.size, output.current_transform().invert());
     let radius = corners.radius;
@@ -462,18 +469,8 @@ pub(super) fn resize_content_behavior(intentional_scale: bool) -> ConstrainScale
     }
 }
 
-pub(super) fn scaled_visual_rect(rect: ferese_layout::Rect, scale: f64) -> ferese_layout::Rect {
-    let scale = scale.clamp(0.0, 1.0);
-    let width = rect.width * scale;
-    let height = rect.height * scale;
-
-    ferese_layout::Rect::new(
-        rect.x + (rect.width - width) / 2.0,
-        rect.y + (rect.height - height) / 2.0,
-        width,
-        height,
-    )
-}
+#[cfg(test)]
+pub(super) use crate::presentation::scaled_visual_rect;
 
 pub(super) fn color_with_alpha(mut color: [f32; 4], alpha: f32) -> [f32; 4] {
     color[3] *= alpha;

compositor/src/render/materials.rs

@@ -128,6 +128,25 @@ pub(super) fn material_element(
     output: &Output,
     surface: &smithay::reexports::wayland_server::protocol::wl_surface::WlSurface,
     surface_geometry: MaterialSurface,
+) -> Option<(AnimatedWindowRenderElement, AnimatedWindowRenderElement)> {
+    let (role, generation) = crate::effects::surface_role(surface)?;
+    material_element_with_role(
+        state,
+        renderer,
+        output,
+        surface,
+        surface_geometry,
+        (role, generation, crate::effects::surface_opacity(surface)),
+    )
+}
+
+pub(super) fn material_element_with_role(
+    state: &mut Ferese,
+    renderer: &mut GlesRenderer,
+    output: &Output,
+    surface: &smithay::reexports::wayland_server::protocol::wl_surface::WlSurface,
+    surface_geometry: MaterialSurface,
+    (role, generation, opacity): (crate::effects::SemanticRole, u64, f32),
 ) -> Option<(AnimatedWindowRenderElement, AnimatedWindowRenderElement)> {
     let MaterialSurface {
         geometry,
@@ -136,13 +155,12 @@ pub(super) fn material_element(
         capture_geometry,
         alpha,
     } = surface_geometry;
-    let (role, generation) = crate::effects::surface_role(surface)?;
     let material = crate::effects::resolve_material(
         role,
         state.theme_settings.material_style,
         state.theme_settings.shell_opacity as f32,
     );
-    let presentation_alpha = crate::effects::surface_opacity(surface) * alpha;
+    let presentation_alpha = opacity * alpha;
     let mode = output.current_mode()?;
     let scale = output.current_scale().fractional_scale();
     let transform = output.current_transform().invert();

compositor/src/render/mod.rs

@@ -1,5 +1,7 @@
 mod backdrop;
 mod capture;
+mod closing;
+pub(crate) use closing::ClosedWindow;
 #[cfg(test)]
 mod corner_tests;
 mod decorations;
@@ -78,7 +80,7 @@ render_elements! {
     Native=NativeTextureElement,
 }
 
-#[derive(Debug)]
+#[derive(Clone, Debug)]
 pub(crate) struct ResizeSnapshot {
     pub texture: GlesTexture,
     pub context: ErasedContextId,
@@ -134,7 +136,7 @@ fn corner_shader_for(source: &str, shape: CornerShape) -> String {
     }
 }
 
-fn window_corner_shape(window: &smithay::desktop::Window) -> CornerShape {
+pub(crate) fn window_corner_shape(window: &smithay::desktop::Window) -> CornerShape {
     // Semantic shell surfaces keep their client-matching circular outlines.
     corner_shape_for_role(
         window

compositor/src/render/overview.rs

@@ -241,6 +241,7 @@ pub(super) fn overview_strip_elements(
                         output,
                         programs.clone(),
                         ConstrainScaleBehavior::Stretch,
+                        None,
                     ));
                 }
             }

compositor/src/render/resources.rs

@@ -8,6 +8,7 @@ use super::*;
 /// context. Desktop policy and animation values do not live in these caches.
 #[derive(Default)]
 pub(crate) struct RenderResources {
+    pub closing: Vec<ClosedWindow>,
     pub(super) windows: HashMap<WindowId, WindowBuffers>,
     pub(super) contexts: HashMap<ErasedContextId, ContextPrograms>,
     pub(super) outputs: HashMap<OutputId, OverviewScrim>,
@@ -71,6 +72,16 @@ impl RenderResources {
     }
 
     pub fn remove_output(&mut self, id: OutputId) {
+        let removed: Vec<_> = self
+            .closing
+            .iter()
+            .filter(|window| window.output == id)
+            .map(|window| window.id)
+            .collect();
+        self.closing.retain(|window| window.output != id);
+        for id in removed {
+            self.remove_window(id);
+        }
         self.outputs.remove(&id);
 
         for window in self.windows.values_mut() {
@@ -124,6 +135,16 @@ impl RenderResources {
     }
 
     pub fn forget_context(&mut self, context: &ErasedContextId) {
+        let removed: Vec<_> = self
+            .closing
+            .iter()
+            .filter(|window| &window.snapshot.context == context)
+            .map(|window| window.id)
+            .collect();
+        self.closing.retain(|window| &window.snapshot.context != context);
+        for id in removed {
+            self.remove_window(id);
+        }
         self.contexts.remove(context);
 
         for window in self.windows.values_mut() {

compositor/src/render/scene.rs

@@ -124,8 +124,8 @@ pub(crate) fn sampled_output_elements(
             return None;
         }
         let sample = frame.windows.get(&id)?;
-        let visual = scaled_visual_rect(sample.rect, sample.close_scale);
-        let close_alpha = sample.close_alpha;
+        let visual = sample.rect;
+        let close_alpha = sample.alpha;
         let decoration_progress = sample.geometry.decorations.clamp(0.0, 1.0);
 
         Some((window.clone(), id, sample, visual, decoration_progress, close_alpha))
@@ -145,7 +145,16 @@ pub(crate) fn sampled_output_elements(
             .collect::<Vec<_>>()
     };
 
+    let live = windows.iter().map(|(_, id, ..)| *id).collect();
     for (window, id, sample, visual, decoration_progress, close_alpha) in windows {
+        elements.extend(super::closing::elements(
+            state,
+            renderer,
+            output,
+            Some(id),
+            &live,
+            frame.delta,
+        ));
         let constrain = rounded_visual_rect(visual, output_geometry.loc);
         let material_surface = window
             .toplevel()
@@ -165,7 +174,7 @@ pub(crate) fn sampled_output_elements(
         let rounded_clip_program = corner_program(&mut state.render, renderer, shape);
         let pixels = corners.rect;
         // Only overview/close intentionally scale the complete application.
-        let scale_content = frame.overview.is_presenting() || sample.close_scale != 1.0;
+        let scale_content = sample.scale_content;
         let behavior = resize_content_behavior(scale_content);
 
         let dim = sample.dim;
@@ -227,13 +236,33 @@ pub(crate) fn sampled_output_elements(
                 output,
                 &programs,
             );
-            if !scale_content
-                && let Some(snapshot) = state.render.snapshot(&id)
+            if let Some(snapshot) = state.render.snapshot(&id)
                 && snapshot.context == renderer.context_id().erased()
                 && (snapshot.scale - scale).abs() < 0.001
             {
                 let size = snapshot.texture.size();
-                let visible = Rectangle::new(pixels.loc, (size.w, size.h).into()).intersection(pixels);
+                let (sx, sy) = if scale_content {
+                    (
+                        f64::from(pixels.size.w) / f64::from(size.w),
+                        f64::from(pixels.size.h) / f64::from(size.h),
+                    )
+                } else if let Some(native) = sample.native_size {
+                    (
+                        f64::from(pixels.size.w) / (f64::from(native.width) * scale).round().max(1.0),
+                        f64::from(pixels.size.h) / (f64::from(native.height) * scale).round().max(1.0),
+                    )
+                } else {
+                    (1.0, 1.0)
+                };
+                let visible = Rectangle::new(
+                    pixels.loc,
+                    (
+                        (f64::from(size.w) * sx).round() as i32,
+                        (f64::from(size.h) * sy).round() as i32,
+                    )
+                        .into(),
+                )
+                .intersection(pixels);
                 if let Some(visible) = visible {
                     let clip = framebuffer_clip_rect(
                         pixels,
@@ -247,8 +276,8 @@ pub(crate) fn sampled_output_elements(
                             texture: snapshot.texture.clone(),
                             geometry: visible,
                             source: Rectangle::from_size(Size::from((
-                                f64::from(visible.size.w),
-                                f64::from(visible.size.h),
+                                f64::from(visible.size.w) / sx,
+                                f64::from(visible.size.h) / sy,
                             ))),
                             alpha: crate::presentation::handoff_alpha(snapshot.elapsed) * close_alpha,
                             program: Some(programs.texture.clone()),
@@ -268,6 +297,7 @@ pub(crate) fn sampled_output_elements(
                 output,
                 programs.clone(),
                 behavior,
+                sample.native_size,
             ));
             let source = window.geometry().size;
             if material_surface.is_none()
@@ -322,6 +352,14 @@ pub(crate) fn sampled_output_elements(
             ));
         }
     }
+    elements.extend(super::closing::elements(
+        state,
+        renderer,
+        output,
+        None,
+        &live,
+        frame.delta,
+    ));
     elements.extend(layer_elements(
         state,
         renderer,
@@ -374,7 +412,14 @@ pub(super) fn layer_elements(
             .collect::<Vec<_>>()
     };
 
-    state.render.surfaces.retain(|surface, _| surface.is_alive());
+    state.render.surfaces.retain(|surface, _| {
+        surface.is_alive()
+            || state
+                .render
+                .closing
+                .iter()
+                .any(|window| window.material.as_ref().is_some_and(|(key, ..)| key == surface))
+    });
 
     let mut elements = Vec::new();
     for (geometry, layer) in layers {

compositor/src/state.rs

@@ -9,6 +9,7 @@ mod reconciliation;
 pub(crate) use reconciliation::{DesktopChanges, DesktopOutput, DesktopTransition};
 mod prediction;
 pub(crate) use prediction::FrameScene;
+mod lifecycle;
 mod window_registry;
 mod windows;
 
@@ -19,7 +20,7 @@ use std::sync::Arc;
 use std::time::{Duration, Instant};
 
 use calloop::LoopHandle;
-use ferese_animation::{AnimatedValue, ClientSize, CrossingPolicy, PresentationMode, SpringConfig, WindowGeometry};
+use ferese_animation::{AnimatedValue, ClientSize, PresentationMode, SpringConfig, WindowGeometry};
 use ferese_core::{
     LayoutMode, OutputGeometry, OutputId, OutputWorkspaceMap, WindowPlacement, WorkspaceId, WorkspaceLayout,
     WorkspaceSet,
@@ -98,9 +99,11 @@ use crate::wallpaper::{WallpaperConfig, WallpaperState};
 use crate::window_rules::{WindowRule, resolve as resolve_window_rules};
 use crate::winit::NestedBackend;
 
-const CLOSE_ANIMATION_DURATION: Duration = Duration::from_millis(140);
-const WORKSPACE_SLIDE_DURATION: Duration = Duration::from_millis(220);
-const WORKSPACE_SLIDE_FIRST_FRAME: Duration = Duration::from_millis(8);
+#[cfg(test)]
+use ferese_animation::CrossingPolicy;
+
+#[cfg(test)]
+const SLIDE_SETTLE_TEST_BUDGET: Duration = Duration::from_secs(2);
 
 fn workspace_swipe_is_current(
     outputs: &OutputWorkspaceMap,
@@ -153,7 +156,7 @@ struct FocusSwipe {
 }
 
 impl FocusSwipe {
-    fn position(&self) -> f64 {
+    fn distance(&self) -> f64 {
         let distance = self.destination - self.start;
         // When both columns already fit, give bounded drag feedback and settle
         // back to the unchanged viewport after selecting the next window.
@@ -166,7 +169,29 @@ impl FocusSwipe {
         } else {
             distance
         };
-        self.start + distance * self.progress
+        distance
+    }
+
+    fn position(&self) -> f64 {
+        let progress = if self.to == self.from {
+            ferese_animation::gesture::rubber_band(self.progress.max(0.0), 1.0, 0.55).0
+        } else {
+            self.progress.clamp(0.0, 1.0)
+        };
+        self.start + self.distance() * progress
+    }
+
+    fn release_velocity(&self, bounded: f64, unbounded: f64) -> f64 {
+        let velocity = if self.to == self.from {
+            if self.progress <= 0.0 {
+                0.0
+            } else {
+                unbounded * ferese_animation::gesture::rubber_band(self.progress, 1.0, 0.55).1
+            }
+        } else {
+            bounded
+        };
+        self.distance() * velocity
     }
 }
 
@@ -175,12 +200,13 @@ struct WorkspaceSlideItem {
     workspace: WorkspaceId,
     start: SlideOffset,
     target: SlideOffset,
+    velocity: SlideOffset,
 }
 
 #[derive(Clone)]
 struct WorkspaceSlide {
     items: Vec<WorkspaceSlideItem>,
-    elapsed: Duration,
+    spring: SpringConfig,
     held_progress: Option<f64>,
     gesture: Option<(WorkspaceId, WorkspaceId, SwipeDirection)>,
 }
@@ -190,12 +216,14 @@ impl WorkspaceSlide {
         let movement = SlideOffset::for_swipe(direction);
         let mut items = previous
             .map(|slide| {
-                let progress = slide.progress();
+                let progress = slide.held_progress;
                 slide
                     .items
                     .into_iter()
                     .map(|mut item| {
-                        item.start = item.start.between(item.target, progress);
+                        if let Some(progress) = progress {
+                            item.start = item.start.between(item.target, progress);
+                        }
                         item
                     })
                     .collect::<Vec<_>>()
@@ -209,6 +237,7 @@ impl WorkspaceSlide {
                 workspace: from,
                 start: SlideOffset::default(),
                 target: movement,
+                velocity: SlideOffset::default(),
             });
         }
         if let Some(item) = items.iter_mut().find(|item| item.workspace == to) {
@@ -218,30 +247,64 @@ impl WorkspaceSlide {
                 workspace: to,
                 start: movement.opposite(),
                 target: SlideOffset::default(),
+                velocity: SlideOffset::default(),
             });
         }
 
         Self {
             items,
-            elapsed: WORKSPACE_SLIDE_FIRST_FRAME,
+            spring: SpringConfig {
+                stiffness: 320.0,
+                damping: 2.0 * 320.0_f64.sqrt(),
+                position_tolerance: 0.00001,
+                velocity_tolerance: 0.00001,
+                ..SpringConfig::default()
+            },
             held_progress: None,
             gesture: None,
         }
     }
 
-    fn progress(&self) -> f64 {
-        self.progress_at(Duration::ZERO)
+    fn position(&self, item: &WorkspaceSlideItem, delta: Duration) -> SlideOffset {
+        if let Some(progress) = self.held_progress {
+            return item.start.between(item.target, progress);
+        }
+        let mut x = AnimatedValue {
+            current: item.start.x,
+            target: item.target.x,
+            velocity: item.velocity.x,
+        };
+        let mut y = AnimatedValue {
+            current: item.start.y,
+            target: item.target.y,
+            velocity: item.velocity.y,
+        };
+        x.advance(delta, self.spring);
+        y.advance(delta, self.spring);
+        SlideOffset {
+            x: x.current,
+            y: y.current,
+        }
     }
 
-    fn progress_at(&self, delta: Duration) -> f64 {
-        self.held_progress.unwrap_or_else(|| {
-            let elapsed = self.elapsed.saturating_add(delta).min(WORKSPACE_SLIDE_DURATION);
-            smoothstep(elapsed.as_secs_f64() / WORKSPACE_SLIDE_DURATION.as_secs_f64())
-        })
+    fn moving(&self) -> bool {
+        self.items
+            .iter()
+            .any(|item| item.start != item.target || item.velocity != SlideOffset::default())
+    }
+
+    fn release_with_velocity(&mut self, committed: bool, velocity: f64) {
+        for item in &mut self.items {
+            item.velocity = SlideOffset {
+                x: (item.target.x - item.start.x) * velocity,
+                y: (item.target.y - item.start.y) * velocity,
+            };
+        }
+        self.release(committed);
     }
 
     fn release(&mut self, committed: bool) {
-        let progress = self.progress();
+        let progress = self.held_progress.unwrap_or(0.0);
         for item in &mut self.items {
             let position = item.start.between(item.target, progress);
             if !committed && let Some((from, to, direction)) = self.gesture {
@@ -255,12 +318,36 @@ impl WorkspaceSlide {
         }
         self.held_progress = None;
         self.gesture = None;
-        self.elapsed = Duration::ZERO;
     }
 
     fn advance(&mut self, delta: Duration) -> bool {
-        self.elapsed = (self.elapsed + delta).min(WORKSPACE_SLIDE_DURATION);
-        self.elapsed < WORKSPACE_SLIDE_DURATION
+        if self.held_progress.is_some() {
+            return true;
+        }
+        let mut moving = false;
+        for item in &mut self.items {
+            let mut x = AnimatedValue {
+                current: item.start.x,
+                target: item.target.x,
+                velocity: item.velocity.x,
+            };
+            let mut y = AnimatedValue {
+                current: item.start.y,
+                target: item.target.y,
+                velocity: item.velocity.y,
+            };
+            moving |= x.advance(delta, self.spring);
+            moving |= y.advance(delta, self.spring);
+            item.start = SlideOffset {
+                x: x.current,
+                y: y.current,
+            };
+            item.velocity = SlideOffset {
+                x: x.velocity,
+                y: y.velocity,
+            };
+        }
+        moving
     }
 
     fn contains(&self, workspace: WorkspaceId) -> bool {
@@ -269,43 +356,16 @@ impl WorkspaceSlide {
 
     #[cfg(test)]
     fn offset(&self, workspace: WorkspaceId, width: f64, height: f64) -> (f64, f64) {
-        let progress = self.progress();
         let position = self
             .items
             .iter()
             .find(|item| item.workspace == workspace)
-            .map(|item| item.start.between(item.target, progress))
+            .map(|item| self.position(item, Duration::ZERO))
             .unwrap_or_default();
         (position.x * width, position.y * height)
     }
 }
 
-#[derive(Clone, Copy, Debug, Default)]
-struct ClosingAnimation {
-    progress: f64,
-    close_sent: bool,
-}
-
-impl ClosingAnimation {
-    fn advance(&mut self, delta: Duration, animations_enabled: bool) -> bool {
-        if self.close_sent {
-            return false;
-        }
-
-        self.progress = if animations_enabled {
-            (self.progress + delta.as_secs_f64() / CLOSE_ANIMATION_DURATION.as_secs_f64()).min(1.0)
-        } else {
-            1.0
-        };
-        if self.progress < 1.0 {
-            return false;
-        }
-
-        self.close_sent = true;
-        true
-    }
-}
-
 fn scaled_animation_duration(duration: Duration, enabled: bool, speed: f64) -> Duration {
     if enabled {
         duration.div_f64(speed)
@@ -373,7 +433,7 @@ pub struct Ferese {
     pub(crate) inactive_dim: crate::config::InactiveDimSettings,
     animations_enabled: bool,
     animation_speed: f64,
-    spring_config: SpringConfig,
+    pub(crate) spring_config: SpringConfig,
     viewport_spring_config: SpringConfig,
     pub(crate) output_profiles: Vec<OutputProfile>,
     pub(crate) autostart: Vec<DaemonConfig>,
@@ -784,6 +844,13 @@ impl Ferese {
         self.animation_speed = config.animation_speed;
         self.spring_config = config.spring_config;
         self.viewport_spring_config = config.viewport_spring_config;
+        for slide in self.workspace_slides.values_mut() {
+            slide.spring = SpringConfig {
+                position_tolerance: 0.00001,
+                velocity_tolerance: 0.00001,
+                ..self.viewport_spring_config
+            };
+        }
         self.output_profiles = config.output_profiles;
         self.autostart = config.autostart;
         if daemons_changed && let Some(runner) = self.daemons.clone() {
@@ -940,12 +1007,6 @@ fn natural_floating_rect(bounds: Rect, size: ClientSize) -> Rect {
     )
 }
 
-fn smoothstep(progress: f64) -> f64 {
-    let progress = progress.clamp(0.0, 1.0);
-
-    progress * progress * (3.0 - 2.0 * progress)
-}
-
 fn restored_scrolling_world_x(had_geometry: bool, visual_x: f64, viewport_x: f64, target_world_x: f64) -> f64 {
     if had_geometry {
         visual_x + viewport_x
@@ -1044,20 +1105,60 @@ impl ClientData for ClientState {
 
 #[cfg(test)]
 mod tests {
+    #[test]
+    fn workspace_reversal_keeps_position_and_velocity() {
+        let from = WorkspaceId(1);
+        let to = WorkspaceId(2);
+        let mut slide = WorkspaceSlide::new(None, from, to, SwipeDirection::Up);
+        slide.advance(Duration::from_millis(40));
+        let before: Vec<_> = slide
+            .items
+            .iter()
+            .map(|item| (item.workspace, item.start, item.velocity))
+            .collect();
+        let reversed = WorkspaceSlide::new(Some(slide), to, from, SwipeDirection::Down);
+        for (id, position, velocity) in before {
+            let item = reversed.items.iter().find(|item| item.workspace == id).unwrap();
+            assert_eq!(item.start, position);
+            assert_eq!(item.velocity, velocity);
+            assert!(velocity.y < 0.0);
+        }
+    }
+    #[test]
+    fn viewport_limit_uses_resisted_position_and_release_velocity() {
+        let swipe = FocusSwipe {
+            workspace: WorkspaceId(1),
+            from: WindowId(1),
+            to: WindowId(1),
+            direction: Direction::Right,
+            gesture_direction: SwipeDirection::Left,
+            start: 20.0,
+            destination: 20.0,
+            progress: 2.0,
+        };
+        assert!(swipe.position() > 20.0 && swipe.position() < 84.0);
+        assert!(swipe.release_velocity(0.0, 3.0) > 0.0);
+        let mut released = AnimatedValue {
+            current: swipe.position(),
+            target: swipe.start,
+            velocity: swipe.release_velocity(0.0, 3.0),
+        };
+        let initial = released;
+        released.advance(Duration::from_micros(1), SpringConfig::default());
+        assert!((released.current - initial.current - initial.velocity * 1e-6).abs() < 1e-6);
+        released.advance(Duration::from_secs(2), SpringConfig::default());
+        assert_eq!(released.current, swipe.start);
+    }
     #[test]
     fn sampling_slide_progress_matches_advancing_without_mutating_the_slide() {
         let slide = WorkspaceSlide::new(None, WorkspaceId(1), WorkspaceId(2), SwipeDirection::Left);
-
-        for delta in [Duration::ZERO, Duration::from_millis(8), Duration::from_secs(1)] {
+        for delta in [Duration::ZERO, Duration::from_millis(16), Duration::from_millis(100)] {
             let mut advanced = slide.clone();
             advanced.advance(delta);
-            assert_eq!(slide.progress_at(delta), advanced.progress());
-            assert_eq!(slide.elapsed, WORKSPACE_SLIDE_FIRST_FRAME);
+            for (before, after) in slide.items.iter().zip(&advanced.items) {
+                assert_eq!(slide.position(before, delta), after.start);
+            }
         }
-
-        let mut held = slide;
-        held.held_progress = Some(0.37);
-        assert_eq!(held.progress_at(Duration::from_secs(1)), 0.37);
     }
 
     #[test]
@@ -1080,15 +1181,6 @@ mod tests {
         }
     }
 
-    #[test]
-    fn disabling_motion_finishes_an_in_progress_close_once() {
-        let mut animation = ClosingAnimation::default();
-        assert!(!animation.advance(Duration::from_millis(35), true));
-        assert!(animation.advance(Duration::ZERO, false));
-        assert_eq!(animation.progress, 1.0);
-        assert!(!animation.advance(Duration::ZERO, false));
-    }
-
     #[test]
     fn workspace_drag_cancels_when_focus_or_target_ownership_changes() {
         let mut outputs = OutputWorkspaceMap::default();
@@ -1241,7 +1333,7 @@ mod tests {
             slide.release(committed);
             assert_eq!(slide.offset(from, 1000.0, 1000.0), (0.0, -400.0));
             assert_eq!(slide.offset(to, 1000.0, 1000.0), (0.0, 600.0));
-            assert!(!slide.advance(WORKSPACE_SLIDE_DURATION));
+            assert!(!slide.advance(SLIDE_SETTLE_TEST_BUDGET));
             let active = if committed { to } else { from };
             assert_eq!(slide.offset(active, 1000.0, 1000.0), (0.0, 0.0));
         }
@@ -1253,14 +1345,14 @@ mod tests {
         let second = WorkspaceId(2);
         let third = WorkspaceId(3);
         let mut previous = WorkspaceSlide::new(None, first, second, SwipeDirection::Up);
-        previous.advance(WORKSPACE_SLIDE_DURATION / 3);
+        previous.advance(Duration::from_millis(40));
         let mut slide = WorkspaceSlide::new(Some(previous), second, third, SwipeDirection::Up);
         slide.gesture = Some((second, third, SwipeDirection::Up));
         slide.held_progress = Some(0.25);
         let position = slide.offset(second, 1000.0, 1000.0);
         slide.release(false);
         assert_eq!(slide.offset(second, 1000.0, 1000.0), position);
-        slide.advance(WORKSPACE_SLIDE_DURATION);
+        slide.advance(SLIDE_SETTLE_TEST_BUDGET);
         assert_eq!(slide.offset(second, 1000.0, 1000.0), (0.0, 0.0));
     }
 
@@ -1279,13 +1371,13 @@ mod tests {
             let mut slide = WorkspaceSlide::new(None, from, to, direction);
             assert!(slide.contains(from));
             assert!(slide.contains(to));
-            assert!(slide.advance(WORKSPACE_SLIDE_DURATION / 2));
+            assert!(slide.advance(Duration::from_millis(50)));
             let outgoing = slide.offset(from, width, height);
             let incoming = slide.offset(to, width, height);
             assert!((incoming.0 - outgoing.0).abs() == outgoing_target.0.abs());
             assert!((incoming.1 - outgoing.1).abs() == outgoing_target.1.abs());
 
-            assert!(!slide.advance(WORKSPACE_SLIDE_DURATION));
+            assert!(!slide.advance(SLIDE_SETTLE_TEST_BUDGET));
             assert_eq!(slide.offset(from, width, height), outgoing_target);
             assert_eq!(slide.offset(to, width, height), (0.0, 0.0));
         }
@@ -1297,7 +1389,7 @@ mod tests {
         let second = WorkspaceId(2);
         let third = WorkspaceId(3);
         let mut slide = WorkspaceSlide::new(None, first, second, SwipeDirection::Up);
-        slide.advance(WORKSPACE_SLIDE_DURATION / 3);
+        slide.advance(Duration::from_millis(40));
         let first_position = slide.offset(first, 1600.0, 900.0);
         let second_position = slide.offset(second, 1600.0, 900.0);
 
@@ -1404,24 +1496,6 @@ mod tests {
         assert_eq!(transient, Rect::new(280.0, 210.0, 640.0, 480.0));
     }
 
-    #[test]
-    fn close_easing_is_bounded_and_symmetric() {
-        assert_eq!(smoothstep(-1.0), 0.0);
-        assert_eq!(smoothstep(0.5), 0.5);
-        assert_eq!(smoothstep(2.0), 1.0);
-    }
-
-    #[test]
-    fn close_animation_delays_the_protocol_close_until_it_finishes() {
-        let mut animation = ClosingAnimation::default();
-
-        assert!(!animation.advance(Duration::from_millis(70), true));
-        assert_eq!(animation.progress, 0.5);
-        assert!(animation.advance(Duration::from_millis(70), true));
-        assert!(animation.close_sent);
-        assert!(!animation.advance(Duration::from_secs(1), true));
-    }
-
     #[test]
     fn coupled_right_column_width_keeps_its_right_edge_stable() {
         let spring = SpringConfig {
@@ -1430,6 +1504,7 @@ mod tests {
             damping: 2.0 * 320.0_f64.sqrt(),
             position_tolerance: 0.1,
             velocity_tolerance: 0.1,
+            ..SpringConfig::default()
         };
         let mut width = AnimatedValue::new(980.0);
         let mut viewport = AnimatedValue::new(495.0);

compositor/src/state/animation.rs

@@ -82,6 +82,7 @@ impl Ferese {
         if self.focus_swipe.is_some()
             || !self.paused_workspaces.is_empty()
             || !self.workspace_slides.is_empty()
+            || !self.render.closing.is_empty()
             || !self.dismissing_popups.is_empty()
             || self.render.snapshots().next().is_some()
             || self.overview.needs_tick()
@@ -192,11 +193,22 @@ impl Ferese {
         for (&id, record) in self.windows.records_mut() {
             let selected = selected_window == Some(id);
             let target = if selected { 1.0 } else { 0.0 };
-            let focus = record
-                .focus
-                .get_or_insert_with(|| crate::dimming::DimAnimation::new(target));
+            let focus = record.focus.get_or_insert_with(|| AnimatedValue::new(target));
             let previous = focus.current;
-            active_animation |= focus.advance_visual(target, delta, duration);
+            let changed = focus.target != target;
+            focus.set_target(target);
+            if self.animations_enabled {
+                active_animation |= focus.advance(
+                    if changed { Duration::ZERO } else { delta },
+                    SpringConfig {
+                        position_tolerance: 0.001,
+                        velocity_tolerance: 0.001,
+                        ..self.spring_config
+                    },
+                );
+            } else {
+                focus.snap();
+            }
             dim_changed |= previous != focus.current;
         }
 
@@ -217,19 +229,40 @@ impl Ferese {
             dim_changed |= previous != dim.current;
         }
 
-        let mut ready_to_close = Vec::new();
-        for (id, record) in self.windows.records_mut() {
-            let Some(animation) = &mut record.closing else { continue };
-
-            if animation.advance(delta, self.animations_enabled) {
-                ready_to_close.push(*id);
-            } else if !animation.close_sent {
-                active_animation = true;
+        for (_, record) in self.windows.records_mut() {
+            if let Some(opening) = &mut record.opening {
+                let active = if self.animations_enabled {
+                    opening.advance(
+                        delta,
+                        SpringConfig {
+                            position_tolerance: 0.00001,
+                            velocity_tolerance: 0.00001,
+                            ..self.spring_config
+                        },
+                    )
+                } else {
+                    opening.snap();
+                    false
+                };
+                active_animation |= active;
+                if !active {
+                    record.opening = None;
+                }
             }
         }
-
-        for id in ready_to_close {
-            self.send_window_close(id);
+        let mut finished = Vec::new();
+        self.render.closing.retain_mut(|window| {
+            let active =
+                self.animations_enabled && !self.session_lock.active() && window.advance(delta, self.spring_config);
+            if !active {
+                finished.push(window.id);
+            }
+            active_animation |= active;
+            active
+        });
+        for id in finished {
+            tracing::debug!(?id, "released close presentation");
+            self.render.remove_window(id);
         }
 
         // Include transactions expiring on this dispatch: their waiting time
@@ -325,8 +358,7 @@ impl Ferese {
                 viewport.current = swipe.position();
                 viewport.velocity = 0.0;
             } else if self.animations_enabled {
-                active_animation |=
-                    viewport.advance_with_policy(delta, self.viewport_spring_config, CrossingPolicy::NoCrossing);
+                active_animation |= viewport.advance(delta, self.viewport_spring_config);
             } else {
                 viewport.snap();
             }
@@ -379,8 +411,7 @@ impl Ferese {
                 if zooming {
                     sync_scrolling_coordinates(geometry, world_x, viewport, true);
                 } else if self.animations_enabled {
-                    active_animation |=
-                        world_x.advance_with_policy(delta, self.spring_config, CrossingPolicy::NoCrossing);
+                    active_animation |= world_x.advance(delta, self.spring_config);
                 } else {
                     world_x.snap();
                 }
@@ -392,7 +423,7 @@ impl Ferese {
 
             if let Some((_, width)) = record.coupled_width.as_mut() {
                 let width_active = if self.animations_enabled {
-                    width.advance_with_policy(delta, self.viewport_spring_config, CrossingPolicy::NoCrossing)
+                    width.advance(delta, self.viewport_spring_config)
                 } else {
                     width.snap();
                     false
@@ -462,6 +493,9 @@ impl Ferese {
             self.send_shell_snapshots();
             active_animation = true;
         }
+        if !self.overview.is_active() {
+            self.retarget_overview();
+        }
         active_animation |= self
             .overview
             .advance(delta, self.spring_config, self.animations_enabled);
@@ -525,10 +559,9 @@ impl Ferese {
             else {
                 continue;
             };
-            let progress = slide.progress_at(delta);
 
             for item in &slide.items {
-                let position = item.start.between(item.target, progress);
+                let position = slide.position(item, delta);
                 offsets.insert(
                     item.workspace,
                     (position.x * f64::from(size.w), position.y * f64::from(size.h)),
@@ -573,7 +606,7 @@ fn record_needs_tick(
     mapped: impl FnOnce() -> bool,
 ) -> bool {
     if record.resize.is_some()
-        || record.closing.as_ref().is_some_and(|close| !close.close_sent)
+        || record.opening.is_some()
         || record.focus.as_ref().is_none_or(|motion| motion.needs_update(focus))
     {
         return true;
@@ -610,7 +643,7 @@ mod tests {
 
         WindowRecord {
             geometry: Some(geometry),
-            focus: Some(DimAnimation::new(1.0)),
+            focus: Some(AnimatedValue::new(1.0)),
             dimming: Some(DimAnimation::new(0.0)),
             ..Default::default()
         }
@@ -660,11 +693,11 @@ mod tests {
     }
 
     #[test]
-    fn close_requests_and_coupled_width_cleanup_still_get_their_final_tick() {
+    fn opening_and_coupled_width_cleanup_still_get_their_final_tick() {
         let mut record = settled();
-        record.closing = Some(ClosingAnimation::default());
+        record.opening = Some(AnimatedValue::new(0.0));
         assert!(record_needs_tick(&record, 1.0, 0.0, || false));
-        record.closing.as_mut().unwrap().close_sent = true;
+        record.opening = None;
         assert!(!record_needs_tick(&record, 1.0, 0.0, || true));
         record.coupled_width = Some((WorkspaceId(1), AnimatedValue::new(400.0)));
         assert!(record_needs_tick(&record, 1.0, 0.0, || true));
@@ -871,7 +904,7 @@ mod tests {
         // A settled transaction still has to flush its resume guard; otherwise
         // the next unrelated animation would inherit an old paused workspace.
         state.viewport_animations.get_mut(&workspace).unwrap().snap();
-        state.windows.record_mut(id).unwrap().focus = Some(DimAnimation::new(0.0));
+        state.windows.record_mut(id).unwrap().focus = Some(AnimatedValue::new(0.0));
         state.windows.set_transaction(
             id,
             crate::resize_transaction::ResizeTransaction::new(3.into(), Duration::from_millis(800)),

compositor/src/state/focus.rs

@@ -10,17 +10,13 @@ impl Ferese {
                 (window.toplevel().is_some()
                     && self.window_content_ready(window)
                     && self.windows.geometry(id).is_some()
-                    && self.output_workspaces.focused_output().is_some()
-                    && self.windows.record(*id).is_none_or(|record| record.closing.is_none()))
+                    && self.output_workspaces.focused_output().is_some())
                 .then_some(*id)
             })
             .collect()
     }
 
     pub(crate) fn focus_preview_output(&self, id: WindowId) -> Option<OutputId> {
-        if self.windows.record(id).is_some_and(|record| record.closing.is_some()) {
-            return None;
-        }
         self.workspaces
             .workspace_for_window(id)
             .and_then(|workspace| self.output_workspaces.output_for_workspace(workspace))

compositor/src/state/hit_testing.rs

@@ -202,12 +202,16 @@ impl Ferese {
     }
 
     pub fn visual_scale_for_window(&self, window: &Window) -> Option<(f64, f64)> {
-        if !self.overview.is_presenting() {
+        let id = self.windows.ids().get(window)?;
+        if !self.overview.is_presenting() && self.windows.record(*id)?.opening.is_none() {
             return Some((1.0, 1.0));
         }
-        let id = self.windows.ids().get(window)?;
         let geometry = self.windows.geometry(id)?;
-        let source = geometry.client.committed_size?;
+        let source = if self.overview.is_presenting() {
+            geometry.client.committed_size?
+        } else {
+            ClientSize::from_rect(geometry.visual.current)
+        };
         let presented = self.presented_window_rect(*id)?;
 
         if source.width <= 0 || source.height <= 0 {

compositor/src/state/lifecycle.rs

@@ -0,0 +1,174 @@
+use super::*;
+use ferese_animation::AnimatedRect;
+use smithay::backend::renderer::Texture;
+use smithay::wayland::compositor::{BufferAssignment, SurfaceAttributes};
+
+impl Ferese {
+    pub(crate) fn capture_close_before_commit(&mut self, surface: &WlSurface) {
+        // At this point cached attributes contain the committed removal, but
+        // on_commit_buffer_handler has not reset the previous renderer state.
+        let removed = with_states(surface, |states| {
+            matches!(
+                states.cached_state.get::<SurfaceAttributes>().current().buffer,
+                Some(BufferAssignment::Removed)
+            )
+        });
+        if removed
+            && let Some(window) = self
+                .windows
+                .id_for_surface(surface)
+                .and_then(|id| self.windows.window(id))
+                .cloned()
+        {
+            self.retain_closed_window(&window);
+        }
+    }
+
+    pub(super) fn retain_closed_window(&mut self, window: &Window) {
+        if !self.animations_enabled || self.session_lock.active() || self.render.closing.len() >= 64 {
+            return;
+        }
+        let Some(&id) = self.windows.ids().get(window) else {
+            return;
+        };
+        if self.render.closing.iter().any(|window| window.id == id) || !self.window_content_ready(window) {
+            return;
+        }
+        let Some(output) = self
+            .space
+            .outputs()
+            .find(|output| self.window_belongs_to_output(id, output))
+            .cloned()
+        else {
+            return;
+        };
+        let Some(output_id) = self.output_id(&output) else {
+            return;
+        };
+        let Some(rect) = self.presented_window_rect(id) else {
+            return;
+        };
+        let record = self.windows.record(id).unwrap();
+        let geometry = record.geometry.unwrap();
+        let decorations = geometry.decorations.clamp(0.0, 1.0);
+        let focus = record.focus.as_ref().map_or(0.0, |focus| focus.current.clamp(0.0, 1.0));
+        let dim = record.dimming.as_ref().map_or(0.0, |dim| dim.current);
+        let mut opacity = record.opening.unwrap_or_else(|| AnimatedValue::new(1.0));
+        opacity.set_target(0.0);
+        let mut bounds = AnimatedRect::new(rect);
+        bounds.velocity = self.overview.presented_velocity(id).unwrap_or(geometry.visual.velocity);
+        if !self.overview.is_presenting()
+            && let Some(slide) = self.workspace_slides.get(&output_id)
+            && let Some(workspace) = self.workspaces.workspace_for_window(id)
+            && let Some(item) = slide.items.iter().find(|item| item.workspace == workspace)
+            && let Some(area) = self.space.output_geometry(&output)
+        {
+            bounds.velocity.x += item.velocity.x * f64::from(area.size.w);
+            bounds.velocity.y += item.velocity.y * f64::from(area.size.h);
+        }
+        if let Some(opening) = record.opening {
+            bounds.velocity = crate::presentation::scaled_visual_velocity(
+                self.overview.presented_rect(id, geometry.visual.current),
+                bounds.velocity,
+                0.97 + 0.03 * opening.current,
+                0.03 * opening.velocity,
+            );
+        }
+        bounds.set_target(crate::presentation::scaled_visual_rect(rect, 0.98));
+        let mut source_geometry = window.geometry();
+        if !self.overview.is_presenting() {
+            let size = ClientSize::from_rect(geometry.visual.current);
+            source_geometry.size = (size.width, size.height).into();
+        }
+        let order: Vec<_> = if self.overview.is_active() {
+            self.windows
+                .overview_windows()
+                .filter_map(|window| self.windows.ids().get(window).copied())
+                .collect()
+        } else {
+            self.space
+                .elements()
+                .rev()
+                .filter_map(|window| self.windows.ids().get(window).copied())
+                .collect()
+        };
+        let below = order
+            .iter()
+            .position(|candidate| *candidate == id)
+            .and_then(|index| order.get(index + 1))
+            .copied();
+        let used = self.render.snapshots().map(|snapshot| snapshot.bytes()).sum::<usize>()
+            + self
+                .render
+                .closing
+                .iter()
+                .map(|window| window.snapshot.bytes())
+                .sum::<usize>();
+        let remaining = crate::presentation::SNAPSHOT_BUDGET.saturating_sub(used);
+        let scale = output.current_scale().fractional_scale();
+        let result = if let Some(backend) = &self.nested_backend {
+            match backend.try_borrow_mut() {
+                Ok(mut backend) => crate::render::capture_resize_snapshot(
+                    backend.renderer(),
+                    window,
+                    source_geometry,
+                    scale,
+                    remaining,
+                ),
+                Err(_) => return,
+            }
+        } else if let Some(backend) = &mut self.direct_backend {
+            backend.capture_resize_snapshot(window, source_geometry, &output, remaining)
+        } else {
+            return;
+        };
+        match result {
+            Ok(Some(snapshot)) => {
+                tracing::debug!(?id, bytes = snapshot.bytes(), "retained close presentation");
+                let size = snapshot.texture.size();
+                let material = window.toplevel().and_then(|toplevel| {
+                    let surface = toplevel.wl_surface();
+                    let (role, generation) = crate::effects::surface_role(surface)?;
+                    (role == crate::effects::SemanticRole::Modal).then(|| {
+                        (
+                            surface.clone(),
+                            role,
+                            generation,
+                            crate::effects::surface_opacity(surface),
+                        )
+                    })
+                });
+                let radius = if material.is_some() {
+                    self.theme_settings.material_radius
+                } else {
+                    self.theme_settings.window_radius
+                } * decorations;
+                let client = window.geometry().size;
+                let fill = (!self.overview.is_presenting()
+                    && material.is_none()
+                    && (client.w < source_geometry.size.w || client.h < source_geometry.size.h))
+                    .then_some(self.theme_settings.surface_base_color.0);
+                self.render.closing.push(crate::render::ClosedWindow {
+                    id,
+                    output: output_id,
+                    below,
+                    bounds,
+                    opacity,
+                    snapshot,
+                    source: Rectangle::from_size((f64::from(size.w), f64::from(size.h)).into()),
+                    radius,
+                    shape: crate::render::window_corner_shape(window),
+                    focus,
+                    decorations,
+                    dim,
+                    fill,
+                    material,
+                });
+                self.last_animation_tick = Instant::now();
+                self.defer_output_redraw(output);
+            }
+            Ok(None) => {}
+            Err(error) => tracing::debug!(%error, ?id, "close snapshot unavailable"),
+        }
+    }
+}

compositor/src/state/navigation.rs

@@ -34,9 +34,10 @@ impl Ferese {
             if workspace.fullscreen.is_some() || !matches!(workspace.layout, WorkspaceLayout::Scrolling(_)) {
                 return;
             }
-            let Ok(Some(to)) = workspace.layout.directional_neighbor(from, direction, bounds) else {
+            let Ok(neighbor) = workspace.layout.directional_neighbor(from, direction, bounds) else {
                 return;
             };
+            let to = neighbor.unwrap_or(from);
             let workspace_id = workspace.id;
             let start = self
                 .viewport_animations
@@ -45,7 +46,8 @@ impl Ferese {
                 .or_else(|| workspace.layout.viewport_x())
                 .unwrap_or(0.0);
             let mut candidate = workspace.layout.clone();
-            if let WorkspaceLayout::Scrolling(layout) = &mut candidate
+            if to != from
+                && let WorkspaceLayout::Scrolling(layout) = &mut candidate
                 && layout.slide_focus_from(from, to).is_err()
             {
                 return;
@@ -63,7 +65,11 @@ impl Ferese {
                 direction,
                 gesture_direction,
                 start,
-                destination: candidate.viewport_x().unwrap_or(start),
+                destination: if to == from {
+                    start
+                } else {
+                    candidate.viewport_x().unwrap_or(start)
+                },
                 progress,
             });
             self.swipe.mark_preview_started();
@@ -91,7 +97,9 @@ impl Ferese {
         // Release from the last input position even if no frame rendered that update.
         if current && let Some(viewport) = self.viewport_animations.get_mut(&swipe.workspace) {
             viewport.current = swipe.position();
-            viewport.velocity = 0.0;
+            viewport.velocity = swipe
+                .release_velocity(self.swipe.release_velocity, self.swipe.unbounded_release_velocity)
+                / self.animation_speed;
         }
         let neighbor = self.output_bounds().and_then(|bounds| {
             self.workspaces
@@ -460,6 +468,11 @@ impl Ferese {
         };
         let previous = self.workspace_slides.remove(&output);
         let mut slide = WorkspaceSlide::new(previous, from, to, direction);
+        slide.spring = SpringConfig {
+            position_tolerance: 0.00001,
+            velocity_tolerance: 0.00001,
+            ..self.viewport_spring_config
+        };
         slide.held_progress = Some(progress);
         slide.gesture = Some((from, to, direction));
         self.workspace_slides.insert(output, slide);
@@ -481,7 +494,7 @@ impl Ferese {
             && self.activate_managed_workspace_from_swipe(to, expected);
         if !committed {
             if let Some(slide) = self.workspace_slides.get_mut(&output) {
-                slide.release(false);
+                slide.release_with_velocity(false, self.swipe.release_velocity / self.animation_speed);
             }
             self.last_animation_tick = Instant::now();
             self.relayout();
@@ -497,26 +510,55 @@ impl Ferese {
         workspace: WorkspaceId,
         slide_direction: Option<SwipeDirection>,
     ) {
+        if owner != requested_output {
+            return;
+        }
         let mut previous_slide = self.workspace_slides.remove(&owner);
+        if previous == Some(workspace) {
+            if let Some(slide) = previous_slide {
+                self.workspace_slides.insert(owner, slide);
+            }
+            return;
+        }
         if owner == requested_output
             && let Some(slide) = previous_slide.as_mut()
             && slide
                 .gesture
                 .is_some_and(|(_, to, direction)| to == workspace && Some(direction) == slide_direction)
         {
-            slide.release(true);
+            slide.release_with_velocity(true, self.swipe.release_velocity / self.animation_speed);
             self.last_animation_tick = Instant::now();
             self.workspace_slides.insert(owner, previous_slide.unwrap());
             return;
         }
+        let slide_direction = slide_direction.or_else(|| {
+            let from = previous?;
+            let ids = self
+                .output_workspaces
+                .ordered_workspace_ids(&self.workspaces, owner)
+                .collect::<Vec<_>>();
+            let from = ids.iter().position(|id| *id == from)?;
+            let to = ids.iter().position(|id| *id == workspace)?;
+            Some(if to > from {
+                SwipeDirection::Up
+            } else {
+                SwipeDirection::Down
+            })
+        });
         if owner == requested_output
             && let (Some(from), Some(direction)) = (previous, slide_direction)
             && from != workspace
             && self.animations_enabled
+            && !self.overview.is_presenting()
         {
             self.last_animation_tick = Instant::now();
-            self.workspace_slides
-                .insert(owner, WorkspaceSlide::new(previous_slide, from, workspace, direction));
+            let mut slide = WorkspaceSlide::new(previous_slide, from, workspace, direction);
+            slide.spring = SpringConfig {
+                position_tolerance: 0.00001,
+                velocity_tolerance: 0.00001,
+                ..self.viewport_spring_config
+            };
+            self.workspace_slides.insert(owner, slide);
         }
     }
 

compositor/src/state/prediction.rs

@@ -7,13 +7,15 @@ pub(crate) struct FrameScene {
     pub overview: crate::overview::OverviewMotion,
     // Plane selection and scheduling reuse the activity sampled with this scene.
     pub animating: bool,
+    pub delta: Duration,
 }
 
 pub(crate) struct WindowFrame {
     pub geometry: WindowGeometry,
     pub rect: Rect,
-    pub close_scale: f64,
-    pub close_alpha: f32,
+    pub scale_content: bool,
+    pub native_size: Option<ClientSize>,
+    pub alpha: f32,
     pub focus: f64,
     pub dim: f64,
 }
@@ -68,7 +70,12 @@ impl Ferese {
     }
 
     pub(crate) fn output_has_animations(&self, output: &Output) -> bool {
-        if self.overview.is_animating(self.spring_config)
+        if self
+            .render
+            .closing
+            .iter()
+            .any(|window| Some(window.output) == self.output_id(output))
+            || self.overview.is_animating(self.spring_config)
             || self
                 .dismissing_popups
                 .iter()
@@ -80,7 +87,7 @@ impl Ferese {
         if self
             .output_id(output)
             .and_then(|id| self.workspace_slides.get(&id))
-            .is_some_and(|slide| slide.held_progress.is_none() && slide.elapsed < WORKSPACE_SLIDE_DURATION)
+            .is_some_and(|slide| slide.held_progress.is_none() && slide.moving())
         {
             return true;
         }
@@ -95,8 +102,8 @@ impl Ferese {
             }
 
             if record.resize.is_some()
+                || record.opening.is_some()
                 || self.render.snapshot(&id).is_some()
-                || record.closing.as_ref().is_some_and(|close| !close.close_sent)
                 || record.focus.as_ref().is_some_and(|focus| focus.is_animating())
                 || record.dimming.as_ref().is_some_and(|dim| dim.is_animating())
             {
@@ -117,15 +124,10 @@ impl Ferese {
                     .focus_swipe
                     .as_ref()
                     .is_some_and(|swipe| swipe.workspace == workspace);
-                !held
-                    && viewport.advance_with_policy(
-                        Duration::ZERO,
-                        self.viewport_spring_config,
-                        CrossingPolicy::NoCrossing,
-                    )
+                !held && viewport.advance(Duration::ZERO, self.viewport_spring_config)
             }) || record.coupled_width.as_ref().is_some_and(|(_, width)| {
                 let mut width = *width;
-                width.advance_with_policy(Duration::ZERO, self.viewport_spring_config, CrossingPolicy::NoCrossing)
+                width.advance(Duration::ZERO, self.viewport_spring_config)
             })
         })
     }
@@ -187,12 +189,19 @@ impl Ferese {
                 rect.y += y;
             }
 
-            let mut close = record.closing.as_ref().copied().unwrap_or_default();
-            if record.closing.is_some() && !delta.is_zero() {
-                close.advance(delta, true);
+            let mut opening = record.opening.unwrap_or_else(|| AnimatedValue::new(1.0));
+            if !self.animations_enabled {
+                opening.snap();
+            } else if !delta.is_zero() {
+                opening.advance(
+                    delta,
+                    SpringConfig {
+                        position_tolerance: 0.00001,
+                        velocity_tolerance: 0.00001,
+                        ..self.spring_config
+                    },
+                );
             }
-
-            let eased = smoothstep(close.progress);
             let focused = if self.overview.is_active() {
                 self.overview_selected(id)
             } else {
@@ -211,14 +220,31 @@ impl Ferese {
                 motion.current
             };
 
+            let mut focus = record
+                .focus
+                .unwrap_or_else(|| AnimatedValue::new(if focused { 1.0 } else { 0.0 }));
+            if !delta.is_zero() {
+                focus.advance(
+                    delta,
+                    SpringConfig {
+                        position_tolerance: 0.001,
+                        velocity_tolerance: 0.001,
+                        ..self.spring_config
+                    },
+                );
+            }
+            let presence_scale = 0.97 + 0.03 * opening.current;
+            let native_size = (!overview.is_presenting() && presence_scale != 1.0).then(|| ClientSize::from_rect(rect));
+            let rect = crate::presentation::scaled_visual_rect(rect, presence_scale);
             windows.insert(
                 id,
                 WindowFrame {
                     geometry,
                     rect,
-                    close_scale: 1.0 - eased * 0.02,
-                    close_alpha: (1.0 - eased) as f32,
-                    focus: sample_dim(record.focus.as_ref(), if focused { 1.0 } else { 0.0 }),
+                    scale_content: overview.is_presenting(),
+                    native_size,
+                    alpha: opening.current.clamp(0.0, 1.0) as f32,
+                    focus: focus.current.clamp(0.0, 1.0),
                     dim: sample_dim(record.dimming.as_ref(), 0.0),
                 },
             );
@@ -228,6 +254,7 @@ impl Ferese {
             windows,
             overview,
             animating,
+            delta,
         }
     }
 }
@@ -252,9 +279,9 @@ fn predict_geometry(
     if let Some((mut world, mut viewport, held)) = world
         && !zooming
     {
-        world.advance_with_policy(delta, spring, CrossingPolicy::NoCrossing);
+        world.advance(delta, spring);
         if !held {
-            viewport.advance_with_policy(delta, viewport_spring, CrossingPolicy::NoCrossing);
+            viewport.advance(delta, viewport_spring);
         }
 
         predicted.visual.current.x = world.current - viewport.current;
@@ -262,7 +289,7 @@ fn predict_geometry(
     }
 
     if let Some(mut width) = width {
-        width.advance_with_policy(delta, viewport_spring, CrossingPolicy::NoCrossing);
+        width.advance(delta, viewport_spring);
         predicted.visual.current.width = width.current;
         predicted.visual.velocity.width = width.velocity;
     }
@@ -454,7 +481,7 @@ mod tests {
         state.focused_window = Some(id);
         state
             .windows
-            .update(id, |record| record.focus = Some(crate::dimming::DimAnimation::new(1.0)));
+            .update(id, |record| record.focus = Some(AnimatedValue::new(1.0)));
         state.focused_window = Some(other_id);
         assert!(state.output_has_pending_visual_changes(&output));
         state.animations_enabled = false;

compositor/src/state/window_registry.rs

@@ -21,9 +21,10 @@ pub(crate) struct WindowRecord {
     pub title: String,
     pub metadata_revision: u64,
     pub resize: Option<ResizeTransaction>,
-    pub focus: Option<crate::dimming::DimAnimation>,
+    pub focus: Option<AnimatedValue>,
     pub dimming: Option<crate::dimming::DimAnimation>,
-    pub(super) closing: Option<super::ClosingAnimation>,
+    pub opening: Option<AnimatedValue>,
+    pub mapped_once: bool,
     pub world_x: Option<(WorkspaceId, AnimatedValue)>,
     pub coupled_width: Option<(WorkspaceId, AnimatedValue)>,
     pub maximized: bool,
@@ -302,8 +303,8 @@ mod tests {
             record.resize_anchor = Some((true, false, Rect::new(0., 0., 800., 600.)));
             record.column_width_pending = true;
             record.rules_applied = true;
-            record.focus = Some(crate::dimming::DimAnimation::new(1.0));
-            record.closing = Some(super::super::ClosingAnimation::default());
+            record.focus = Some(AnimatedValue::new(1.0));
+            record.opening = Some(AnimatedValue::new(0.0));
             record.world_x = Some((WorkspaceId(1), AnimatedValue::new(50.0)));
             record.coupled_width = Some((WorkspaceId(1), AnimatedValue::new(800.0)));
         });

compositor/src/state/windows.rs

@@ -417,6 +417,7 @@ impl Ferese {
     }
 
     pub fn remove_tiled_window(&mut self, window: &Window) {
+        self.retain_closed_window(window);
         // Uncommitted toplevels have not entered a workspace yet.
         self.space.unmap_elem(window);
         let Some(id) = self.windows.remove(window) else {
@@ -493,7 +494,13 @@ impl Ferese {
             return;
         }
 
-        let used: usize = self.render.snapshots().map(|snapshot| snapshot.bytes()).sum();
+        let used: usize = self.render.snapshots().map(|snapshot| snapshot.bytes()).sum::<usize>()
+            + self
+                .render
+                .closing
+                .iter()
+                .map(|window| window.snapshot.bytes())
+                .sum::<usize>();
         let remaining = crate::presentation::SNAPSHOT_BUDGET.saturating_sub(used);
         let result = if let Some(backend) = &self.nested_backend {
             // Commit dispatch does not run inside the Winit event callback;
@@ -557,6 +564,20 @@ impl Ferese {
             return;
         };
 
+        if let Some(record) = self.windows.record_mut(id)
+            && !record.mapped_once
+        {
+            record.mapped_once = true;
+            if self.animations_enabled {
+                record.opening = Some(AnimatedValue {
+                    current: 0.0,
+                    target: 1.0,
+                    velocity: 0.0,
+                });
+                self.last_animation_tick = Instant::now();
+            }
+        }
+
         let fullscreen = self
             .workspaces
             .workspace_for_window(id)
@@ -648,35 +669,16 @@ impl Ferese {
     }
 
     pub fn close_focused_window(&mut self) {
-        let Some(focused) = self.focused_window else {
-            return;
-        };
-
-        if !self.animations_enabled {
+        if let Some(focused) = self.focused_window {
             self.send_window_close(focused);
-            return;
         }
-
-        self.windows.update(focused, |record| {
-            record.closing.get_or_insert_default();
-        });
-        crate::backends::direct::render_window(self, focused);
     }
 
     pub(crate) fn close_managed_window(&mut self, id: WindowId) -> bool {
         if self.windows.window(id).is_none() {
             return false;
         }
-
-        if self.animations_enabled {
-            self.windows.update(id, |record| {
-                record.closing.get_or_insert_default();
-            });
-            crate::backends::direct::render_window(self, id);
-        } else {
-            self.send_window_close(id);
-        }
-
+        self.send_window_close(id);
         true
     }
 

compositor/src/winit.rs

@@ -95,6 +95,7 @@ pub fn init(event_loop: &mut EventLoop<Ferese>, state: &mut Ferese) -> Result<()
             let mut backend = backend.borrow_mut();
             match event {
                 WinitEvent::Resized { size, scale_factor } => {
+                    tracing::debug!(target: "ferese::nested_input", ?size, scale_factor, "host resized nested output");
                     let scale = normalized_scale(scale_factor);
                     let rate = backend
                         .window()
@@ -115,7 +116,13 @@ pub fn init(event_loop: &mut EventLoop<Ferese>, state: &mut Ferese) -> Result<()
                     }
                     backend.window().request_redraw();
                 }
-                WinitEvent::Input(event) => state.process_input_event(event),
+                WinitEvent::Input(event) => {
+                    let kind = std::mem::discriminant(&event);
+                    state.process_input_event(event);
+                    tracing::debug!(target: "ferese::nested_input", ?kind,
+                        pointer = ?state.seat.get_pointer().map(|pointer| pointer.current_location()),
+                        "host input in nested output");
+                }
                 WinitEvent::Redraw => {
                     state.advance_animations(Instant::now());
                     let age = backend.buffer_age().unwrap_or(0);

crates/ferese-animation/Cargo.toml

@@ -7,3 +7,4 @@ rust-version.workspace = true
 
 [dependencies]
 ferese-layout = { path = "../ferese-layout" }
+serde.workspace = true

crates/ferese-animation/src/gesture.rs

@@ -0,0 +1,135 @@
+//! Input estimation and destination selection; all post-release motion uses springs.
+use std::{collections::VecDeque, time::Duration};
+
+#[derive(Default, Debug)]
+pub struct VelocityTracker {
+    samples: VecDeque<(Duration, f64)>,
+}
+
+impl VelocityTracker {
+    pub fn push(&mut self, time: Duration, position: f64) {
+        if !position.is_finite() {
+            return;
+        }
+        if let Some(&(last, _)) = self.samples.back() {
+            if time < last {
+                return;
+            }
+            if time == last {
+                self.samples.pop_back();
+            }
+        }
+        self.samples.push_back((time, position));
+        while self
+            .samples
+            .front()
+            .is_some_and(|(t, _)| time.saturating_sub(*t) > Duration::from_millis(100))
+            || self.samples.len() > 32
+        {
+            self.samples.pop_front();
+        }
+    }
+
+    pub fn velocity(&self, now: Duration) -> f64 {
+        let Some(&(last, origin)) = self.samples.back() else {
+            return 0.0;
+        };
+        if now.saturating_sub(last) > Duration::from_millis(40) || self.samples.len() < 2 {
+            return 0.0;
+        }
+        // Fit positions relative to the newest sample, with time normalized to
+        // the history horizon to avoid ill-conditioned powers of tiny seconds.
+        let degree = if self.samples.len() >= 3 { 2 } else { 1 };
+        let mut matrix = [[0.0; 4]; 3];
+        for &(time, position) in &self.samples {
+            let t = -last.saturating_sub(time).as_secs_f64() / 0.1;
+            let powers = [1.0, t, t * t, t * t * t, t * t * t * t];
+            for row in 0..=degree {
+                for col in 0..=degree {
+                    matrix[row][col] += powers[row + col];
+                }
+                matrix[row][degree + 1] += powers[row] * (position - origin);
+            }
+        }
+        for col in 0..=degree {
+            let pivot = (col..=degree)
+                .max_by(|&a, &b| matrix[a][col].abs().total_cmp(&matrix[b][col].abs()))
+                .unwrap();
+            matrix.swap(col, pivot);
+            let divisor = matrix[col][col];
+            if divisor.abs() < 1e-12 {
+                let (first, position) = self.samples[0];
+                let dt = last.saturating_sub(first).as_secs_f64();
+                return if dt > 0.0 { (origin - position) / dt } else { 0.0 };
+            }
+            for entry in col..=degree + 1 {
+                matrix[col][entry] /= divisor;
+            }
+            for row in 0..=degree {
+                if row == col {
+                    continue;
+                }
+                let factor = matrix[row][col];
+                for entry in col..=degree + 1 {
+                    matrix[row][entry] -= factor * matrix[col][entry];
+                }
+            }
+        }
+        matrix[1][degree + 1] / 0.1
+    }
+}
+
+pub fn project(position: f64, velocity: f64, rate: f64) -> f64 {
+    if !velocity.is_finite() || !(0.0..1.0).contains(&rate) || rate == 0.0 {
+        return position;
+    }
+    position - velocity / (1000.0 * rate.ln())
+}
+
+/// Nonlinear resistance, bounded by `extent`; the derivative transfers the
+/// velocity of the displayed (resisted) position into the release spring.
+pub fn rubber_band(distance: f64, extent: f64, resistance: f64) -> (f64, f64) {
+    if !distance.is_finite() || !extent.is_finite() || extent <= 0.0 || !resistance.is_finite() || resistance <= 0.0 {
+        return (0.0, 0.0);
+    }
+    let denominator = 1.0 + resistance * distance.abs() / extent;
+    (
+        distance.signum() * extent * (1.0 - denominator.recip()),
+        resistance / denominator.powi(2),
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn rubber_band_is_bounded_symmetric_and_has_matching_velocity() {
+        for x in [0.0, 1.0, 100.0, 10000.0] {
+            let (position, derivative) = rubber_band(x, 64.0, 0.55);
+            assert!((0.0..64.0).contains(&position));
+            assert_eq!(rubber_band(-x, 64.0, 0.55).0, -position);
+            let measured = (rubber_band(x + 0.0001, 64.0, 0.55).0 - rubber_band(x - 0.0001, 64.0, 0.55).0) / 0.0002;
+            assert!((measured - derivative).abs() < 1e-6);
+        }
+    }
+    #[test]
+    fn quadratic_velocity_and_pause() {
+        let mut tracker = VelocityTracker::default();
+        for ms in [0, 7, 19, 40, 60, 90] {
+            let t = ms as f64 / 1000.0;
+            tracker.push(Duration::from_millis(ms), 100.0 * t + 200.0 * t * t);
+        }
+        assert!((tracker.velocity(Duration::from_millis(90)) - 136.0).abs() < 1e-8);
+        assert_eq!(tracker.velocity(Duration::from_millis(140)), 0.0);
+        assert!((project(0.0, 1.0, 0.997) - 0.332833082957).abs() < 1e-10);
+    }
+    #[test]
+    fn duplicate_and_out_of_order_samples() {
+        let mut tracker = VelocityTracker::default();
+        tracker.push(Duration::ZERO, 0.0);
+        tracker.push(Duration::from_millis(10), 1.0);
+        tracker.push(Duration::from_millis(10), 2.0);
+        tracker.push(Duration::from_millis(5), 99.0);
+        assert!((tracker.velocity(Duration::from_millis(10)) - 200.0).abs() < 1e-10);
+    }
+}

crates/ferese-animation/src/lib.rs

@@ -2,7 +2,10 @@ use std::time::Duration;
 
 use ferese_layout::Rect;
 
+mod settings;
 mod spring;
+pub use settings::{MotionSettings, SpringSettings};
+pub mod gesture;
 
 /// Crossing behavior belongs to the property, not the physical solver.
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
@@ -20,6 +23,7 @@ pub struct SpringConfig {
     pub damping: f64,
     pub position_tolerance: f64,
     pub velocity_tolerance: f64,
+    pub crossing: CrossingPolicy,
 }
 
 impl Default for SpringConfig {
@@ -30,6 +34,7 @@ impl Default for SpringConfig {
             damping: 53.0,
             position_tolerance: 0.1,
             velocity_tolerance: 0.1,
+            crossing: CrossingPolicy::NoCrossing,
         }
     }
 }
@@ -44,6 +49,7 @@ impl SpringConfig {
             damping: non_negative_or(self.damping, defaults.damping),
             position_tolerance: positive_or(self.position_tolerance, defaults.position_tolerance),
             velocity_tolerance: positive_or(self.velocity_tolerance, defaults.velocity_tolerance),
+            crossing: self.crossing,
         }
     }
 }
@@ -71,6 +77,14 @@ pub struct AnimatedValue {
 }
 
 impl AnimatedValue {
+    pub fn needs_update(&self, target: f64) -> bool {
+        self.target != target || self.is_animating()
+    }
+
+    pub fn is_animating(&self) -> bool {
+        self.current != self.target || self.velocity != 0.0
+    }
+
     pub fn new(value: f64) -> Self {
         let value = finite_or_zero(value);
 
@@ -86,13 +100,7 @@ impl AnimatedValue {
     }
 
     pub fn retarget_preserving_motion(&mut self, target: f64) {
-        let target = finite_or_zero(target);
-        let direction = (target - self.current).signum();
-
-        if direction != 0.0 && self.velocity.signum() != direction {
-            self.velocity *= 0.35;
-        }
-        self.target = target;
+        self.set_target(target);
     }
 
     pub fn snap(&mut self) {
@@ -100,9 +108,9 @@ impl AnimatedValue {
         self.velocity = 0.0;
     }
 
-    /// Compatibility entry point; existing presentation properties do not cross.
+    /// Advance with the spring's configured crossing policy.
     pub fn advance(&mut self, delta: Duration, config: SpringConfig) -> bool {
-        self.advance_with_policy(delta, config, CrossingPolicy::NoCrossing)
+        self.advance_with_policy(delta, config, config.crossing)
     }
 
     pub fn advance_with_policy(&mut self, delta: Duration, config: SpringConfig, policy: CrossingPolicy) -> bool {
@@ -156,7 +164,7 @@ impl AnimatedRect {
     }
 
     pub fn advance(&mut self, delta: Duration, config: SpringConfig) -> bool {
-        self.advance_with_policy(delta, config, CrossingPolicy::NoCrossing)
+        self.advance_with_policy(delta, config, config.crossing)
     }
 
     pub fn advance_with_policy(&mut self, delta: Duration, config: SpringConfig, policy: CrossingPolicy) -> bool {
@@ -304,9 +312,7 @@ pub struct WindowGeometry {
 /// Maximized/fullscreen geometry and decorations share a clock, including on reversal.
 #[derive(Clone, Copy, Debug, PartialEq)]
 struct ZoomTransition {
-    from: Rect,
-    decorations_from: f64,
-    progress: AnimatedValue,
+    decorations: AnimatedValue,
 }
 
 impl WindowGeometry {
@@ -359,28 +365,12 @@ impl WindowGeometry {
         let rect = normalized_rect(rect);
         let before = (self.visual.current, self.decorations);
         if self.mode != mode || (self.zoom.is_some() && self.logical != rect) {
-            let mut progress = AnimatedValue::new(0.0);
-            progress.set_target(1.0);
-            let from = self.visual.current;
-            let distance = [
-                rect.x - from.x,
-                rect.y - from.y,
-                rect.width - from.width,
-                rect.height - from.height,
-            ];
-            let velocity = self.visual.velocity;
-            let speed = [velocity.x, velocity.y, velocity.width, velocity.height];
-            let squared_length = distance.iter().map(|value| value * value).sum::<f64>();
-            if squared_length > 0.001 {
-                let projected = distance.iter().zip(speed).map(|(d, v)| d * v).sum::<f64>() / squared_length;
-                // Keep forward momentum; soften a reversal without jumping position.
-                progress.velocity = if projected < 0.0 { projected * 0.35 } else { projected };
-            }
-            self.zoom = Some(ZoomTransition {
-                from: self.visual.current,
-                decorations_from: self.decorations,
-                progress,
-            });
+            let mut decorations = self
+                .zoom
+                .map(|zoom| zoom.decorations)
+                .unwrap_or_else(|| AnimatedValue::new(self.decorations));
+            decorations.set_target(if mode == PresentationMode::Fullscreen { 0.0 } else { 1.0 });
+            self.zoom = Some(ZoomTransition { decorations });
         }
         self.mode = mode;
         self.logical = rect;
@@ -440,55 +430,23 @@ impl WindowGeometry {
             return self.zoom.is_some() || !self.visual.is_settled(config);
         }
 
+        // Retarget the existing rectangle directly: projecting four independent
+        // velocities onto a new scalar progress loses motion on interruption.
+        let geometry_active = self.visual.advance(delta, config);
         if let Some(zoom) = &mut self.zoom {
-            let target = self.visual.target;
-            // Spring tolerances describe pixels and pixels/second, whereas this
-            // spring advances unit progress. Without conversion it snaps several
-            // pixels early on large zooms, visibly shifting the trailing edge.
-            let travel = rect_distance(zoom.from, target)
-                .max((zoom.from.x + zoom.from.width - target.x - target.width).abs())
-                .max((zoom.from.y + zoom.from.height - target.y - target.height).abs())
-                .max(1.0);
-            let config = config.normalized();
-            let progress_config = SpringConfig {
-                position_tolerance: config.position_tolerance / travel,
-                velocity_tolerance: config.velocity_tolerance / travel,
+            let decoration_config = SpringConfig {
+                position_tolerance: 0.00001,
+                velocity_tolerance: 0.00001,
                 ..config
             };
-            let active = zoom
-                .progress
-                .advance_with_policy(delta, progress_config, CrossingPolicy::NoCrossing);
-            let p = zoom.progress.current;
-            let lerp = |a: f64, b: f64| a + (b - a) * p;
-            self.visual.current = Rect::new(
-                lerp(zoom.from.x, target.x),
-                lerp(zoom.from.y, target.y),
-                lerp(zoom.from.width, target.width),
-                lerp(zoom.from.height, target.height),
-            );
-            self.visual.velocity = RectVelocity {
-                x: (target.x - zoom.from.x) * zoom.progress.velocity,
-                y: (target.y - zoom.from.y) * zoom.progress.velocity,
-                width: (target.width - zoom.from.width) * zoom.progress.velocity,
-                height: (target.height - zoom.from.height) * zoom.progress.velocity,
-            };
-            self.decorations = lerp(
-                zoom.decorations_from,
-                if self.mode == PresentationMode::Fullscreen {
-                    0.0
-                } else {
-                    1.0
-                },
-            );
-            if !active {
+            let decorations_active = zoom.decorations.advance(delta, decoration_config);
+            self.decorations = zoom.decorations.current.clamp(0.0, 1.0);
+            if !geometry_active && !decorations_active {
                 self.zoom = None;
-                self.visual.snap();
             }
-            return active;
+            return geometry_active || decorations_active;
         }
-
-        self.visual
-            .advance_with_policy(delta, config, CrossingPolicy::NoCrossing)
+        geometry_active
     }
 
     pub fn inverse_visual_point(&self, x: f64, y: f64) -> Option<(f64, f64)> {
@@ -931,7 +889,7 @@ mod tests {
     }
 
     #[test]
-    fn scalar_spring_softens_opposing_velocity_on_reversal() {
+    fn scalar_spring_preserves_opposing_velocity_on_reversal() {
         let mut value = AnimatedValue::new(0.0);
         value.set_target(1_000.0);
         value.advance(Duration::from_millis(40), SpringConfig::default());
@@ -941,7 +899,7 @@ mod tests {
         value.retarget_preserving_motion(-500.0);
 
         assert!(value.velocity > 0.0);
-        assert_eq!(value.velocity, velocity * 0.35);
+        assert_eq!(value.velocity, velocity);
         assert_eq!(value.current, current);
     }
 

crates/ferese-animation/src/settings.rs

@@ -0,0 +1,298 @@
+use crate::{CrossingPolicy, SpringConfig};
+
+/// One configuration contract for compositor and out-of-process shell motion.
+#[derive(Clone, Copy, Debug, PartialEq, serde::Deserialize)]
+#[serde(default)]
+pub struct MotionSettings {
+    pub enabled: bool,
+    pub reduced_motion: bool,
+    pub speed: f64,
+    pub spring: SpringSettings,
+    pub viewport_spring: SpringSettings,
+}
+
+impl Default for MotionSettings {
+    fn default() -> Self {
+        Self {
+            enabled: true,
+            reduced_motion: false,
+            speed: 1.0,
+            spring: SpringSettings::default(),
+            viewport_spring: SpringSettings::default(),
+        }
+    }
+}
+
+impl MotionSettings {
+    pub fn motion_enabled(self) -> bool {
+        self.enabled && !self.reduced_motion
+    }
+
+    pub fn validate(self) -> Result<(), String> {
+        if !self.speed.is_finite() || self.speed <= 0.0 {
+            return Err("animation speed must be finite and positive".into());
+        }
+        self.spring.resolve(SpringConfig::default())?;
+        self.viewport_config()?;
+        Ok(())
+    }
+
+    pub fn viewport_config(self) -> Result<SpringConfig, String> {
+        let mut settings = self.viewport_spring;
+        if settings.duration_ms.is_none() && settings.damping.is_none() && settings.damping_ratio.is_none() {
+            settings.damping_ratio = Some(1.0);
+        }
+        settings.resolve(SpringConfig {
+            stiffness: 320.0,
+            damping: 2.0 * 320.0_f64.sqrt(),
+            ..SpringConfig::default()
+        })
+    }
+
+    /// Only small opacity changes should use a timed duration.
+    pub fn duration(self, milliseconds: f64) -> std::time::Duration {
+        if !self.motion_enabled() {
+            return std::time::Duration::ZERO;
+        }
+        std::time::Duration::from_secs_f64(milliseconds / 1000.0 / self.speed)
+    }
+}
+
+#[derive(Clone, Copy, Debug, Default, PartialEq, serde::Deserialize)]
+#[serde(default)]
+pub struct SpringSettings {
+    pub mass: Option<f64>,
+    pub stiffness: Option<f64>,
+    pub damping: Option<f64>,
+    pub damping_ratio: Option<f64>,
+    pub duration_ms: Option<f64>,
+    pub bounce: Option<f64>,
+    pub overshoot: bool,
+}
+
+impl SpringSettings {
+    pub fn resolve(self, base: SpringConfig) -> Result<SpringConfig, String> {
+        let positive = |value: f64| value.is_finite() && value > 0.0;
+        let mut config = SpringConfig {
+            mass: self.mass.unwrap_or(base.mass),
+            stiffness: self.stiffness.unwrap_or(base.stiffness),
+            damping: self.damping.unwrap_or(base.damping),
+            crossing: if self.overshoot {
+                CrossingPolicy::AllowOvershoot
+            } else {
+                CrossingPolicy::NoCrossing
+            },
+            ..base
+        };
+        if !positive(config.mass) || !positive(config.stiffness) || !config.damping.is_finite() || config.damping < 0.0
+        {
+            return Err("spring mass/stiffness must be positive and damping nonnegative".into());
+        }
+        if let Some(duration) = self.duration_ms {
+            if self.stiffness.is_some() || self.damping.is_some() || self.damping_ratio.is_some() {
+                return Err("spring duration-ms cannot be combined with stiffness/damping/damping-ratio".into());
+            }
+            let bounce = self.bounce.unwrap_or(0.0);
+            if !positive(duration)
+                || !bounce.is_finite()
+                || (bounce <= -1.0 || bounce >= 1.0)
+                || (bounce > 0.0 && !self.overshoot)
+            {
+                return Err("spring duration-ms must be positive; bounce must be between -1 and 1 (exclusive), and positive bounce requires overshoot".into());
+            }
+            let ratio = if bounce >= 0.0 {
+                1.0 - bounce
+            } else {
+                1.0 / (1.0 + bounce)
+            };
+            let omega = std::f64::consts::TAU / (duration / 1000.0);
+            config.stiffness = config.mass * omega * omega;
+            config.damping = 2.0 * config.mass * omega * ratio;
+        } else {
+            if self.bounce.is_some() {
+                return Err("spring bounce requires duration-ms".into());
+            }
+            if let Some(ratio) = self.damping_ratio {
+                if self.damping.is_some() || !ratio.is_finite() || ratio < 0.0 {
+                    return Err("spring damping-ratio must be nonnegative and cannot be combined with damping".into());
+                }
+                config.damping = 2.0 * ratio * (config.mass * config.stiffness).sqrt();
+            }
+        }
+        if !positive(config.stiffness) || !config.damping.is_finite() {
+            return Err("spring coefficients overflow".into());
+        }
+        // Presentation lifetimes can depend on settlement. An undamped spring
+        // only settles when the first-crossing clamp is enabled.
+        if config.damping == 0.0 && config.crossing == CrossingPolicy::AllowOvershoot {
+            return Err("spring overshoot requires positive damping so motion can settle".into());
+        }
+        Ok(config)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn undamped_overshoot_is_rejected_for_both_motion_properties() {
+        for spring in [
+            SpringSettings {
+                damping: Some(0.0),
+                overshoot: true,
+                ..Default::default()
+            },
+            SpringSettings {
+                damping_ratio: Some(0.0),
+                overshoot: true,
+                ..Default::default()
+            },
+        ] {
+            assert!(
+                MotionSettings {
+                    spring,
+                    ..Default::default()
+                }
+                .validate()
+                .is_err()
+            );
+            assert!(
+                MotionSettings {
+                    viewport_spring: spring,
+                    ..Default::default()
+                }
+                .validate()
+                .is_err()
+            );
+        }
+        assert!(
+            SpringSettings {
+                overshoot: true,
+                ..Default::default()
+            }
+            .resolve(SpringConfig {
+                damping: 0.0,
+                ..Default::default()
+            })
+            .is_err()
+        );
+    }
+
+    #[test]
+    fn undamped_motion_needs_the_crossing_clamp_to_settle() {
+        use crate::AnimatedValue;
+        let clamped = SpringSettings {
+            damping: Some(0.0),
+            ..Default::default()
+        }
+        .resolve(SpringConfig::default())
+        .unwrap();
+        let mut closing = AnimatedValue {
+            current: 1.0,
+            target: 0.0,
+            velocity: 0.0,
+        };
+        let mut free = closing;
+        for _ in 0..3600 {
+            let dt = std::time::Duration::from_secs_f64(1.0 / 60.0);
+            closing.advance(dt, clamped);
+            free.advance(
+                dt,
+                SpringConfig {
+                    crossing: CrossingPolicy::AllowOvershoot,
+                    ..clamped
+                },
+            );
+            assert!(free.current != free.target || free.velocity != 0.0);
+        }
+        assert_eq!(closing.current, closing.target);
+        assert_eq!(closing.velocity, 0.0);
+    }
+
+    #[test]
+    fn viewport_legacy_damping_tracks_overridden_coefficients() {
+        let settings = MotionSettings {
+            viewport_spring: SpringSettings {
+                mass: Some(2.0),
+                stiffness: Some(500.0),
+                ..Default::default()
+            },
+            ..Default::default()
+        };
+        let spring = settings.viewport_config().unwrap();
+        assert_eq!(spring.damping, 2.0 * 1000.0_f64.sqrt());
+        assert_eq!(spring.crossing, CrossingPolicy::NoCrossing);
+        assert!(settings.validate().is_ok());
+    }
+
+    #[test]
+    fn policy_applies_speed_and_reduced_motion_consistently() {
+        let slow = MotionSettings {
+            speed: 0.5,
+            ..Default::default()
+        };
+        assert_eq!(slow.duration(120.0), std::time::Duration::from_millis(240));
+        assert!(
+            !MotionSettings {
+                reduced_motion: true,
+                ..slow
+            }
+            .motion_enabled()
+        );
+        assert!(
+            MotionSettings {
+                reduced_motion: true,
+                ..slow
+            }
+            .duration(120.0)
+            .is_zero()
+        );
+        assert!(MotionSettings { speed: 0.0, ..slow }.validate().is_err());
+    }
+    #[test]
+    fn perceptual_conversion_and_legacy_defaults() {
+        let base = SpringConfig::default();
+        assert_eq!(SpringSettings::default().resolve(base).unwrap(), base);
+        for (bounce, ratio) in [(0.0, 1.0), (0.3, 0.7), (-0.5, 2.0)] {
+            let spring = SpringSettings {
+                duration_ms: Some(500.0),
+                bounce: Some(bounce),
+                overshoot: bounce > 0.0,
+                ..Default::default()
+            }
+            .resolve(base)
+            .unwrap();
+            assert!((spring.stiffness - 157.913670417).abs() < 1e-8);
+            assert!((spring.damping / (2.0 * spring.stiffness.sqrt()) - ratio).abs() < 1e-10);
+            assert!((std::f64::consts::TAU * (spring.mass / spring.stiffness).sqrt() - 0.5).abs() < 1e-10);
+        }
+    }
+    #[test]
+    fn rejects_ambiguous_or_nonsettling_configuration() {
+        for settings in [
+            SpringSettings {
+                duration_ms: Some(300.0),
+                stiffness: Some(100.0),
+                ..Default::default()
+            },
+            SpringSettings {
+                duration_ms: Some(300.0),
+                bounce: Some(0.3),
+                ..Default::default()
+            },
+            SpringSettings {
+                duration_ms: Some(300.0),
+                bounce: Some(-1.0),
+                ..Default::default()
+            },
+            SpringSettings {
+                duration_ms: Some(300.0),
+                bounce: Some(1.0),
+                overshoot: true,
+                ..Default::default()
+            },
+        ] {
+            assert!(settings.resolve(SpringConfig::default()).is_err());
+        }
+    }
+}

crates/ferese-animation/src/traces.rs

@@ -110,7 +110,7 @@ fn capture_old_golden_trace_and_retarget_policy() {
     value.retarget_preserving_motion(-500.0);
     println!("old reversal: {}, {}", value.current, value.velocity);
     assert_eq!(value.current, position);
-    assert_eq!(value.velocity, velocity * 0.35);
+    assert_eq!(value.velocity, velocity);
 }
 
 #[test]
@@ -282,7 +282,7 @@ fn retarget_golden_policy_values() {
     old.retarget_preserving_motion(2000.);
     close(old.velocity, 9837.123292018367, 1e-9);
     old.retarget_preserving_motion(-500.);
-    close(old.velocity, 3442.993152206428, 1e-9);
+    close(old.velocity, 9837.123292018367, 1e-9);
 }
 
 #[test]
@@ -342,7 +342,7 @@ fn rapid_retarget_trace_preserves_position_and_the_golden_policy() {
     let before = value;
     value.retarget_preserving_motion(-500.0);
     assert_eq!(value.current, before.current);
-    assert_eq!(value.velocity, before.velocity * 0.35);
+    assert_eq!(value.velocity, before.velocity);
     clock.sample(Duration::from_millis(81), &mut value, SpringConfig::default());
     assert_ne!(value.velocity, 0.0);
 
@@ -350,11 +350,11 @@ fn rapid_retarget_trace_preserves_position_and_the_golden_policy() {
     value.current = 318.94300938241565;
     value.velocity = 9837.123292018367;
     value.retarget_preserving_motion(-500.0);
-    close(value.velocity, 3442.993152206428, 1e-9);
+    close(value.velocity, 9837.123292018367, 1e-9);
 }
 
 #[test]
-fn interrupted_resize_and_zoom_targets_are_c0_continuous() {
+fn interrupted_resize_and_zoom_targets_preserve_position_and_velocity() {
     let initial = Rect::new(0., 0., 400., 300.);
     let mut geometry = WindowGeometry::new(initial, None);
     geometry.set_logical_target(Rect::new(100., 50., 900., 600.), Duration::ZERO);
@@ -366,8 +366,10 @@ fn interrupted_resize_and_zoom_targets_are_c0_continuous() {
         PresentationMode::Normal,
     ] {
         let before = (geometry.visual.current, geometry.decorations);
+        let velocity = geometry.visual.velocity;
         geometry.set_presentation_mode(Rect::new(200., 100., 700., 500.), mode, Duration::from_millis(40));
         assert_eq!((geometry.visual.current, geometry.decorations), before);
+        assert_eq!(geometry.visual.velocity, velocity);
         geometry.advance(Duration::ZERO, SpringConfig::default(), true);
         assert_eq!((geometry.visual.current, geometry.decorations), before);
         geometry.advance(Duration::from_millis(16), SpringConfig::default(), true);

docs/configuration.md

@@ -114,7 +114,8 @@ Changing default width preserves manually resized columns.
 
 ## Animations
 
-Set animation speed in Settings → Motion or edit the `animations` block in
+Continuum is Ferese's shared compositor and shell motion system. Set animation
+speed in Settings → Motion or edit the `animations` block in
 `~/.config/ferese/config.kdl`. Changes apply live. Start with `speed` if you only
 want faster or slower transitions; you do not need to change the springs.
 
@@ -151,7 +152,20 @@ You can omit either spring block to keep its defaults.
 | `animations.spring.damping` | number ≥ 0 | `53` | Spring damping |
 | `animations.viewport-spring.mass` | number > 0 | `1` | Scrolling spring mass |
 | `animations.viewport-spring.stiffness` | number > 0 | `320` | Scrolling stiffness |
-| `animations.viewport-spring.damping-ratio` | number > 0 | `1` | `1` is critically damped |
+| `animations.viewport-spring.damping-ratio` | number ≥ 0 | `1` | `1` is critically damped; zero requires overshoot disabled |
+
+Both `spring` and `viewport-spring` also accept these keys:
+
+| Key | Type | Default | Meaning |
+| --- | --- | --- | --- |
+| `damping-ratio` | number ≥ 0 | Derived from coefficients for `spring`; `1` for `viewport-spring` | Alternative to `damping`; zero requires overshoot disabled |
+| `duration-ms` | number > 0 | Unset | Response parameter instead of stiffness/damping; not a completion deadline |
+| `bounce` | number strictly between −1 and 1 | `0` with `duration-ms` | Requires `duration-ms`; positive values also require overshoot |
+| `overshoot` | boolean | `false` | Allow target crossings for this spring; requires positive damping |
+
+`mass`, `stiffness` and `damping` are accepted in both blocks. The viewport's
+default damping ratio tracks changes to mass and stiffness unless you supply
+`damping`, `damping-ratio` or `duration-ms` explicitly.
 
 ### Speed and reduced motion
 
@@ -166,17 +180,44 @@ immediate. Reduced motion takes precedence over `enabled #true`; setting
 `speed 0` is invalid. These settings control Ferese's animations, not animations
 inside other applications.
 
+Overview can reverse while moving, and workspace changes slide in their navigation
+direction. Workspace and scrolling gestures carry their release velocity into
+the settling spring. Scrolling gestures resist at viewport limits and spring back.
+Window opening starts when content is available; closing waits for the application
+to unmap, then animates its retained image. Input and application close requests
+remain responsive while the animations finish.
+
 ### Spring tuning
 
 `spring` controls window position and size motion, fullscreen/maximize zoom and
-overview entrance motion. `viewport-spring` controls the scrolling viewport and
-the column-width animation that runs with it. Shell popups and theme fades use
-timed transitions, so the spring parameters do not change their curves.
+overview entrance and dismissal, opening/closing windows, focus emphasis, shell
+popups and notifications. `viewport-spring` controls the scrolling viewport,
+workspace slides and the column-width animation that runs with scrolling.
+Continuum shares the analytic spring solver and motion settings between the
+compositor and shell. Small opacity changes (hover, dimming, theme fades) may
+still use timed transitions.
 
-Spring motion has no fixed duration. Its settling time depends on the distance
-to the target, current velocity and the spring parameters. The `animations`
-block has no settings for per-animation durations, custom curves or animation
-shaders.
+Spring settling time depends on distance, velocity and tolerances. In either
+spring block, you can use duration and bounce instead of stiffness and damping:
+
+```kdl
+animations {
+    spring {
+        duration-ms 300.0
+        bounce 0.0
+    }
+}
+```
+
+`duration-ms` is a response parameter, not a fixed completion deadline. With
+`T = duration-ms / 1000`, Continuum uses `omega = 2*pi/T`,
+`stiffness = mass*omega^2` and `damping = 2*mass*omega*zeta`.
+`zeta = 1-bounce` for nonnegative bounce, otherwise `zeta = 1/(1+bounce)`.
+Bounce defaults to zero and must be strictly between -1 and 1. Positive bounce
+requires `overshoot #true` in that spring block. Do not combine `duration-ms`
+with `stiffness`, `damping` or `damping-ratio`; existing physical settings keep
+working. This conversion does not guarantee the same perceptual duration or
+settling time as Apple's springs.
 
 With the other parameters unchanged, higher stiffness makes motion faster and
 higher mass makes it slower. Damping controls how quickly velocity dies away.
@@ -184,14 +225,16 @@ The default window spring is slightly overdamped, close to critical damping;
 the viewport spring is critically damped.
 
 For `viewport-spring`, `damping-ratio 1.0` is critical damping, values below `1`
-are underdamped and values above `1` are overdamped. The window spring uses a
-damping coefficient instead: critical damping is
+are underdamped and values above `1` are overdamped. Both spring blocks accept a
+damping ratio or a damping coefficient, but not both; critical damping is
 `damping = 2 * sqrt(stiffness * mass)`. Ferese stops spring animations
-at their first target crossing, so lowering damping does not make them bounce
-past the target.
+at their first target crossing by default. `overshoot #true` allows that spring
+to move past its target; opacity remains bounded. Overshoot is never enabled globally.
 
-Mass, stiffness, damping ratio and speed must be finite and greater than zero.
-The window spring's damping coefficient may also be zero. Invalid edits leave
+Mass, stiffness and speed must be finite and greater than zero.
+Damping coefficients and damping ratios may be zero only with overshoot disabled,
+so the first-crossing clamp can settle the animation. Overshoot requires positive
+damping; otherwise closing popups could wait indefinitely for settlement. Invalid edits leave
 the last accepted configuration active.
 
 ## Appearance
@@ -225,7 +268,7 @@ one appearance.
 | `appearance.corner-radius` | number ≥ 0 | unset | Legacy fallback for shell radius |
 | `appearance.inactive-dim.enabled` | boolean | `false` | Dim unfocused windows |
 | `appearance.inactive-dim.amount` | number 0–1 | `0.15` | Darkening strength |
-| `appearance.inactive-dim.duration-ms` | number ≥ 0 | `150` | Dimming and focus-ring transition; 0 snaps |
+| `appearance.inactive-dim.duration-ms` | number ≥ 0 | `150` | Dimming transition; 0 snaps |
 | `theme.typography.font-family` | string | `"Inter"` | Shell, Settings and overview font |
 | `theme.background.path` | string | bundled Ferese wallpaper | Wallpaper image path; an existing selection overrides the default |
 | `theme.background.mode` | `"fill"`, `"fit"` | `"fill"` | Crop or letterbox |

scripts/tests/test_overview_damage_isolated.py

@@ -2,7 +2,9 @@
 
 FERESE_TEST_OVERVIEW_DAMAGE=1 FERESE_TEST_BINARY=target/release/ferese \
     FERESE_TEST_CTL=target/release/feresectl python3 scripts/tests/test_overview_damage_isolated.py
-Requires a Wayland host, foot and dbus-daemon. Never connects clients to the host.
+Set FERESE_TEST_TERMINAL=alacritty to use Alacritty instead of foot.
+Requires a Wayland host, the selected terminal and dbus-daemon.
+Never connects clients to the host.
 """
 import errno
 import json
@@ -22,6 +24,8 @@ class OverviewDamageTest(unittest.TestCase):
         repo = Path(__file__).resolve().parents[2]
         binary = repo / os.environ.get("FERESE_TEST_BINARY", "target/debug/ferese")
         control = repo / os.environ.get("FERESE_TEST_CTL", "target/debug/feresectl")
+        terminal = os.environ.get("FERESE_TEST_TERMINAL", "foot")
+        self.assertIn(terminal, ("foot", "alacritty"))
         children = []
         with tempfile.TemporaryDirectory(prefix="ferese-overview-damage-") as temporary:
             root = Path(temporary)
@@ -36,7 +40,7 @@ class OverviewDamageTest(unittest.TestCase):
 
             env = dict(os.environ, WAYLAND_DISPLAY=str(display), XDG_RUNTIME_DIR=str(runtime),
                        XDG_CONFIG_HOME=str(root / "config"), XDG_STATE_HOME=str(root / "state"),
-                       FERESE_TRACE_PERFORMANCE="1", RUST_LOG="ferese=info")
+                       FERESE_TRACE_PERFORMANCE="1", RUST_LOG="ferese=info,ferese::nested_input=debug")
             env.pop("WAYLAND_SOCKET", None)
             env.pop("FERESE_SHELL_CONTROL_SOCKET", None)
             log_path = root / "compositor.log"
@@ -71,6 +75,13 @@ class OverviewDamageTest(unittest.TestCase):
                 wait_for(lambda: len(reports()) >= count + 2)
                 return reports()[-1]
 
+            def assert_quiet(label, report):
+                print(label + ":", report, flush=True)
+                with self.subTest(stage=label):
+                    self.assertEqual(report["frames"], 0, str(report) + "\n" + log_path.read_text()[-5000:])
+                    self.assertEqual(report["damaged_pixels"], 0, str(report))
+                    self.assertGreater(report["no_damage_frames"], 0, str(report))
+
             writer = None
             with log_path.open("w") as log:
                 try:
@@ -89,7 +100,9 @@ class OverviewDamageTest(unittest.TestCase):
                         app = f"ferese.test.overview.{index}"
                         client = (["sh", "-c", 'cat "$1"; sleep 120', "sh", str(fifo)]
                                   if index == 0 else ["sleep", "120"])
-                        launch(["foot", "--app-id", app, *client], stdout=log, stderr=log)
+                        terminal_command = (["alacritty", "--class", app, "--command", *client]
+                                            if terminal == "alacritty" else ["foot", "--app-id", app, *client])
+                        launch(terminal_command, stdout=log, stderr=log)
                         wait_for(lambda: any(window["app_id"] == app and window["width"] > 0
                                              for window in command("get-windows")))
 
@@ -106,21 +119,31 @@ class OverviewDamageTest(unittest.TestCase):
                     command("toggle-overview")
                     time.sleep(2)
                     quiet = stationary_interval()
-                    self.assertEqual(quiet["frames"], 0, str(quiet))
-                    self.assertEqual(quiet["damaged_pixels"], 0, str(quiet))
-                    self.assertGreater(quiet["no_damage_frames"], 0, str(quiet))
+                    assert_quiet("Settled overview", quiet)
 
                     count = len(reports())
                     os.write(writer, b"Live overview content must still update.\n")
                     wait_for(lambda: len(reports()) > count)
                     changed = reports()[-1]
-                    self.assertGreater(changed["frames"], 0, str(changed))
-                    self.assertGreater(changed["damaged_pixels"], 0, str(changed))
+                    print("Live content update:", changed, flush=True)
+                    with self.subTest(stage="Live content update"):
+                        self.assertGreater(changed["frames"], 0, str(changed))
+                        self.assertGreater(changed["damaged_pixels"], 0, str(changed))
 
                     # The content commit must not start another perpetual repaint.
                     quiet = stationary_interval()
-                    self.assertEqual(quiet["frames"], 0, str(quiet))
-                    self.assertGreater(quiet["no_damage_frames"], 0, str(quiet))
+                    assert_quiet("Settled overview after content update", quiet)
+
+                    # Exercise spring dismissal and reverse it while still in
+                    # flight, then dismiss again and check the settled desktop.
+                    command("toggle-overview")
+                    time.sleep(.08)
+                    command("toggle-overview")
+                    time.sleep(.08)
+                    command("toggle-overview")
+                    time.sleep(2)
+                    quiet = stationary_interval()
+                    assert_quiet("Settled desktop after overview reversals", quiet)
                 finally:
                     if writer is not None:
                         os.close(writer)

scripts/tests/test_unmapped_toplevel_isolated.py

@@ -55,6 +55,7 @@ class UnmappedToplevelTest(unittest.TestCase):
                 XDG_RUNTIME_DIR=str(runtime),
                 XDG_CONFIG_HOME=str(root / "config"),
                 WAYLAND_DISPLAY=host_display,
+                RUST_LOG="ferese=info,ferese::state::lifecycle=debug,ferese::state::animation=debug",
             )
             compositor_binary = repo / os.environ.get("FERESE_TEST_BINARY", "target/debug/ferese")
             ctl_binary = repo / os.environ.get("FERESE_TEST_CTL", "target/debug/feresectl")
@@ -117,6 +118,10 @@ class UnmappedToplevelTest(unittest.TestCase):
                             # Leave a configure/resize outstanding when the buffer is detached.
                             subprocess.run([str(ctl_binary), "toggle-maximized"], env=env,
                                            capture_output=True, check=True)
+                            time.sleep(.08)
+                        if phase == "detached":
+                            self.assertIn("retained close presentation", (root / "compositor.log").read_text(),
+                                          "unmap lost the old buffer before snapshot capture")
 
                         client.stdin.write("\n")
                         client.stdin.flush()
@@ -140,6 +145,11 @@ class UnmappedToplevelTest(unittest.TestCase):
                         [str(ctl_binary), "get-focused-window"], env=env, text=True
                     ))
                     self.assertIsNone(focused, "focus history must not restore a destroyed window")
+                    deadline = time.monotonic() + 3
+                    while "released close presentation" not in (root / "compositor.log").read_text():
+                        if time.monotonic() >= deadline:
+                            self.fail("retained close texture did not settle and release")
+                        time.sleep(.025)
                 finally:
                     if client and client.poll() is None:
                         client.terminate()

shell/ferese-shell/Cargo.toml

@@ -6,6 +6,7 @@ license.workspace = true
 rust-version.workspace = true
 
 [dependencies]
+ferese-animation = { path = "../../crates/ferese-animation" }
 ferese-theme-client = { path = "../../crates/ferese-theme-client" }
 ferese-ipc = { path = "../../crates/ferese-ipc" }
 ferese-theme = { path = "../../crates/ferese-theme" }

shell/ferese-shell/src/config.rs

@@ -360,6 +360,7 @@ fn parse_document(
         .map_err(|error| ferese_config::Error::from(error.to_string()))
     {
         Ok(config) => {
+            config.animations.validate().map_err(ferese_config::Error::from)?;
             config.notifications.validate().map_err(ferese_config::Error::from)?;
             config.desktop_widgets.validate().map_err(ferese_config::Error::from)?;
             let mut theme = shell_theme(&config.theme);
@@ -577,6 +578,17 @@ pub(crate) fn config_path() -> Option<PathBuf> {
 
 #[cfg(test)]
 mod tests {
+    #[test]
+    fn rejects_undamped_overshoot_before_publication() {
+        for property in ["spring", "viewport-spring"] {
+            for coefficient in ["damping", "damping-ratio"] {
+                let source = format!("animations {{ {property} {{ {coefficient} 0; overshoot #true; }}; }}");
+                let error = parse_test_source(&source).unwrap_err().to_string();
+                assert!(error.contains("overshoot requires positive damping"), "{error}");
+            }
+        }
+    }
+
     #[test]
     fn desktop_clock_parses_and_rejects_invalid_reload_values() {
         let clock = parse_test_source(

shell/ferese-shell/src/main.rs

@@ -904,6 +904,7 @@ impl FereseShell {
         motion::configure(config.animations, config.theme.material_radius);
 
         if self.config.animations != config.animations {
+            self.notifications.update_motion_settings(config.animations);
             if let Some(menu) = &mut self.menu {
                 menu.motion.update_settings(config.animations);
             }

shell/ferese-shell/src/motion.rs

@@ -1,45 +1,12 @@
-//! Draw-only popup transform; layout stays stable while its presentation animates.
 use cosmic::iced::advanced::{Clipboard, Layout, Renderer as _, Shell, Widget, layout, mouse, renderer, widget};
 use cosmic::iced::{Event, Length, Rectangle, Size, Transformation, Vector};
 use cosmic::{Element, Theme};
 
 pub type Regions = std::sync::Arc<std::sync::Mutex<Vec<[f32; 5]>>>;
 
-#[derive(Clone, Copy, Debug, PartialEq, serde::Deserialize)]
-#[serde(default)]
-pub(crate) struct Settings {
-    enabled: bool,
-    reduced_motion: bool,
-    speed: f64,
-}
+pub(crate) use ferese_animation::MotionSettings as Settings;
+use ferese_animation::{AnimatedValue, SpringConfig};
 
-impl Default for Settings {
-    fn default() -> Self {
-        Self {
-            enabled: true,
-            reduced_motion: false,
-            speed: 1.0,
-        }
-    }
-}
-
-impl Settings {
-    fn hover_duration(self) -> std::time::Duration {
-        self.duration(120.0)
-    }
-
-    pub(crate) fn duration(self, milliseconds: f64) -> std::time::Duration {
-        if !self.enabled || self.reduced_motion {
-            return std::time::Duration::ZERO;
-        }
-        let speed = if self.speed.is_finite() && self.speed > 0.0 {
-            self.speed.clamp(0.01, 100.0)
-        } else {
-            1.0
-        };
-        std::time::Duration::from_secs_f64(milliseconds / 1000.0 / speed)
-    }
-}
 static SETTINGS: std::sync::OnceLock<std::sync::RwLock<Settings>> = std::sync::OnceLock::new();
 static SHELL_RADIUS: std::sync::atomic::AtomicU32 = std::sync::atomic::AtomicU32::new(14.0_f32.to_bits());
 
@@ -56,25 +23,29 @@ pub(crate) fn configure(settings: Settings, radius: f32) {
         .unwrap() = settings;
 }
 
-pub(crate) fn notification_duration() -> std::time::Duration {
-    SETTINGS
+pub(crate) fn settings() -> Settings {
+    *SETTINGS
         .get_or_init(|| std::sync::RwLock::new(Settings::default()))
         .read()
         .unwrap()
-        .duration(180.0)
 }
 
 pub(crate) struct PopupMotion {
-    start: f32,
-    target: f32,
+    value: AnimatedValue,
     started: Option<std::time::Instant>,
     settings: Settings,
 }
 
 impl PopupMotion {
     pub(crate) fn update_settings(&mut self, settings: Settings) {
-        let now = std::time::Instant::now();
-        self.start = self.progress_at(now);
+        self.update_settings_at(settings, std::time::Instant::now());
+    }
+
+    fn update_settings_at(&mut self, settings: Settings, now: std::time::Instant) {
+        self.value = self.sample(now);
+        // Stored velocities use simulation seconds. Preserve visible velocity
+        // when changing the clock rate during an in-flight transition.
+        self.value.velocity *= self.settings.speed / settings.speed;
         self.settings = settings;
         if self.started.is_some() {
             self.started = Some(now);
@@ -83,8 +54,11 @@ impl PopupMotion {
 
     pub(crate) fn new(settings: Settings) -> Self {
         Self {
-            start: 0.0,
-            target: 1.0,
+            value: AnimatedValue {
+                current: 0.0,
+                target: 1.0,
+                velocity: 0.0,
+            },
             started: None,
             settings,
         }
@@ -96,36 +70,49 @@ impl PopupMotion {
         }
     }
 
-    pub(crate) fn progress_at(&self, now: std::time::Instant) -> f32 {
+    fn sample(&self, now: std::time::Instant) -> AnimatedValue {
+        let mut value = self.value;
         let Some(started) = self.started else {
-            return self.start;
+            return value;
         };
-        let duration = self.settings.duration(if self.target == 1.0 { 200.0 } else { 140.0 });
-        if duration.is_zero() {
-            return self.target;
+        if !self.settings.motion_enabled() {
+            value.snap();
+            return value;
         }
-        let t = (now.saturating_duration_since(started).as_secs_f32() / duration.as_secs_f32()).min(1.0);
-        if t == 1.0 {
-            return self.target;
-        }
-        self.start + (self.target - self.start) * t * t * (3.0 - 2.0 * t)
+        let spring = self
+            .settings
+            .spring
+            .resolve(SpringConfig::default())
+            .expect("validated motion settings");
+        value.advance(
+            now.saturating_duration_since(started).mul_f64(self.settings.speed),
+            SpringConfig {
+                position_tolerance: 0.00001,
+                velocity_tolerance: 0.00001,
+                ..spring
+            },
+        );
+        value
+    }
+
+    pub(crate) fn progress_at(&self, now: std::time::Instant) -> f32 {
+        self.sample(now).current as f32
     }
 
     pub(crate) fn progress(&self) -> f32 {
         self.progress_at(std::time::Instant::now())
     }
-
     pub(crate) fn closing(&self) -> bool {
-        self.target == 0.0
+        self.value.target == 0.0
     }
-
     pub(crate) fn animating(&self) -> bool {
-        self.progress() != self.target
+        let value = self.sample(std::time::Instant::now());
+        value.current != value.target || value.velocity != 0.0
     }
 
     pub(crate) fn retarget(&mut self, target: f32, now: std::time::Instant) {
-        self.start = self.progress_at(now);
-        self.target = target;
+        self.value = self.sample(now);
+        self.value.set_target(f64::from(target));
         self.started = Some(now);
     }
 }
@@ -158,7 +145,7 @@ pub(crate) fn button<'a, M: Clone + 'a>(
         duration: SETTINGS
             .get()
             .map_or_else(Settings::default, |settings| *settings.read().unwrap())
-            .hover_duration(),
+            .duration(120.0),
     })
 }
 
@@ -506,6 +493,28 @@ impl widget::Operation for CollectRegions {
 
 #[cfg(test)]
 mod tests {
+    #[test]
+    fn zero_damping_with_crossing_clamp_finishes_popup_close() {
+        let settings = super::Settings {
+            spring: ferese_animation::SpringSettings {
+                damping: Some(0.0),
+                ..Default::default()
+            },
+            ..Default::default()
+        };
+        settings.validate().unwrap();
+        let now = std::time::Instant::now();
+        let mut motion = super::PopupMotion::new(settings);
+        motion.begin(now);
+        let opened = now + std::time::Duration::from_secs(1);
+        assert_eq!(motion.sample(opened).current, 1.0);
+        motion.retarget(0.0, opened);
+        let closed = motion.sample(opened + std::time::Duration::from_secs(1));
+        assert!(motion.closing());
+        assert_eq!(closed.current, closed.target);
+        assert_eq!(closed.velocity, 0.0);
+    }
+
     use super::*;
 
     #[test]
@@ -529,19 +538,48 @@ mod tests {
     }
 
     #[test]
-    fn popup_waits_for_configuration_then_opens_and_closes_faster() {
+    fn popup_waits_for_configuration_and_preserves_reversal_velocity() {
         let now = std::time::Instant::now();
         let mut motion = PopupMotion::new(Settings::default());
         assert_eq!(motion.progress_at(now + std::time::Duration::from_secs(30)), 0.0);
         motion.begin(now);
-        // Later configure/focus notifications must not restart the clock.
-        motion.begin(now + std::time::Duration::from_millis(90));
-        assert!((motion.progress_at(now + std::time::Duration::from_millis(100)) - 0.5).abs() < 0.00001);
-        assert_eq!(motion.progress_at(now + std::time::Duration::from_millis(200)), 1.0);
-        motion.retarget(0.0, now + std::time::Duration::from_millis(200));
+        let reverse = now + std::time::Duration::from_millis(90);
+        let before = motion.sample(reverse);
+        motion.begin(reverse);
+        assert_eq!(motion.sample(reverse), before);
+        motion.retarget(0.0, reverse);
+        let after = motion.sample(reverse);
+        assert_eq!(after.current, before.current);
+        assert_eq!(after.velocity, before.velocity);
         assert!(motion.closing());
-        assert!((motion.progress_at(now + std::time::Duration::from_millis(270)) - 0.5).abs() < 0.00001);
-        assert_eq!(motion.progress_at(now + std::time::Duration::from_millis(340)), 0.0);
+        assert_eq!(motion.progress_at(reverse + std::time::Duration::from_secs(2)), 0.0);
+    }
+
+    #[test]
+    fn live_speed_change_preserves_visible_velocity_and_reduced_motion_snaps() {
+        let now = std::time::Instant::now();
+        let mut motion = PopupMotion::new(Settings::default());
+        motion.begin(now);
+        let time = now + std::time::Duration::from_millis(90);
+        let before = motion.sample(time);
+        motion.update_settings_at(
+            Settings {
+                speed: 2.0,
+                ..Settings::default()
+            },
+            time,
+        );
+        let after = motion.sample(time);
+        assert_eq!(after.current, before.current);
+        assert_eq!(after.velocity * 2.0, before.velocity);
+        motion.update_settings_at(
+            Settings {
+                reduced_motion: true,
+                ..Settings::default()
+            },
+            time,
+        );
+        assert_eq!(motion.progress_at(time), 1.0);
     }
 
     #[test]
@@ -560,7 +598,7 @@ mod tests {
         let before = motion.progress_at(reopen);
         motion.retarget(1.0, reopen);
         assert_eq!(motion.progress_at(reopen), before);
-        assert_eq!(motion.progress_at(reopen + std::time::Duration::from_secs(1)), 1.0);
+        assert_eq!(motion.progress_at(reopen + std::time::Duration::from_secs(2)), 1.0);
         for settings in [
             Settings {
                 reduced_motion: true,
@@ -632,7 +670,7 @@ mod tests {
                 speed: 0.75,
                 ..Settings::default()
             }
-            .hover_duration(),
+            .duration(120.0),
             std::time::Duration::from_millis(160)
         );
         for settings in [
@@ -645,9 +683,9 @@ mod tests {
                 ..Settings::default()
             },
         ] {
-            assert!(settings.hover_duration().is_zero());
+            assert!(settings.duration(120.0).is_zero());
             let mut hover = HoverState::default();
-            assert!(!hover.advance(1.0, std::time::Instant::now(), settings.hover_duration()));
+            assert!(!hover.advance(1.0, std::time::Instant::now(), settings.duration(120.0)));
             assert_eq!(hover.current, 1.0);
         }
     }

shell/ferese-shell/src/notifications.rs

@@ -262,7 +262,7 @@ impl Service {
 
 struct Toast {
     id: u32,
-    born: Instant,
+    motion: super::motion::PopupMotion,
     closing: Option<Instant>,
     remaining: Option<Duration>,
     hovered: bool,
@@ -320,30 +320,27 @@ impl Center {
         }
     }
 
+    pub fn update_motion_settings(&mut self, settings: super::motion::Settings) {
+        for toast in &mut self.toasts {
+            toast.motion.update_settings(settings);
+        }
+    }
+
     pub fn unread(&self) -> u32 {
         self.entries.iter().filter(|notice| notice.unread).count() as u32
     }
 
     pub fn visible(&self) -> impl Iterator<Item = (&Notice, f32)> {
-        let duration = super::motion::notification_duration();
         self.toasts.iter().rev().filter_map(move |toast| {
             let notice = self.entries.iter().find(|notice| notice.id == toast.id)?;
-            let p = if duration.is_zero() {
-                if toast.closing.is_some() { 0.0 } else { 1.0 }
-            } else {
-                toast.closing.map_or_else(
-                    || (toast.born.elapsed().as_secs_f32() / duration.as_secs_f32()).min(1.0),
-                    |closing| (1.0 - closing.elapsed().as_secs_f32() / duration.as_secs_f32()).max(0.0),
-                )
-            };
-            Some((notice, p * p * (3.0 - 2.0 * p)))
+            Some((notice, toast.motion.progress().clamp(0.0, 1.0)))
         })
     }
 
     pub fn animating(&self) -> bool {
         self.toasts
             .iter()
-            .any(|toast| toast.closing.is_some() || toast.born.elapsed() < super::motion::notification_duration())
+            .any(|toast| toast.closing.is_some() || toast.motion.animating())
     }
 
     pub fn popup_groups(&self) -> Vec<(&Notice, f32, usize)> {
@@ -433,7 +430,11 @@ impl Center {
             }
         }
         if let Some(toast) = self.toasts.iter_mut().find(|toast| toast.id == id) {
-            toast.closing.get_or_insert_with(Instant::now);
+            if toast.closing.is_none() {
+                let now = Instant::now();
+                toast.closing = Some(now);
+                toast.motion.retarget(0.0, now);
+            }
         }
     }
 
@@ -499,7 +500,11 @@ impl Center {
         if show {
             self.toasts.push_back(Toast {
                 id: notice.id,
-                born: Instant::now(),
+                motion: {
+                    let mut motion = super::motion::PopupMotion::new(super::motion::settings());
+                    motion.begin(Instant::now());
+                    motion
+                },
                 closing: None,
                 remaining: notice.timeout,
                 hovered: group_hovered,
@@ -604,11 +609,8 @@ impl Center {
         for id in expired {
             self.close(id, 1);
         }
-        self.toasts.retain(|toast| {
-            toast
-                .closing
-                .is_none_or(|closing| now.duration_since(closing) < super::motion::notification_duration())
-        });
+        self.toasts
+            .retain(|toast| toast.closing.is_none() || toast.motion.animating());
         let visible: HashSet<_> = self.toasts.iter().map(|toast| toast.id).collect();
         self.entries
             .retain(|notice| !notice.transient || notice.live || visible.contains(&notice.id));

shell/ferese-shell/src/status_ui/lifecycle.rs

@@ -26,9 +26,12 @@ impl FereseShell {
             self.calendar_offset = 0;
         }
 
-        let destroy = self.destroy_menu();
         if !kind.available(&self.status) {
-            return destroy;
+            return Task::none();
+        }
+        if self.menu.as_ref().is_some_and(|menu| menu.kind == Menu::Notifications) {
+            self.notifications.history_open = false;
+            self.notifications.hovered = None;
         }
 
         if kind == Menu::Notifications && self.notifications.ready {
@@ -36,14 +39,6 @@ impl FereseShell {
         }
 
         let notifications = self.sync_notification_surface();
-        let id = window::Id::unique();
-        self.menu = Some(OpenMenu {
-            id,
-            kind,
-            motion: crate::motion::PopupMotion::new(self.config.animations),
-            effects: None,
-            regions: Default::default(),
-        });
         crate::EFFECT_FRAME_PENDING.store(true, std::sync::atomic::Ordering::Relaxed);
         self.status_error = None;
         let parent = self.bar_surface_id;
@@ -70,6 +65,33 @@ impl FereseShell {
         } else {
             kind.height_limit()
         };
+        let positioner = SctkPositioner {
+            anchor_rect: anchor,
+            anchor: 2u32.try_into().unwrap(),
+            gravity: 6u32.try_into().unwrap(),
+            offset: (anchor.width / 2, 8),
+            // The view's autosize widget supplies the active panel's bounds.
+            // Keep initial popup limits broad enough for later panel changes.
+            size_limits: Limits::NONE.max_width(368.0).max_height(720.0_f32.max(height_limit)),
+            constraint_adjustment: 3,
+            ..Default::default()
+        };
+        if let Some(menu) = &mut self.menu {
+            menu.kind = kind;
+            menu.motion.retarget(1.0, Instant::now());
+            return Task::batch([
+                notifications,
+                cosmic::iced::platform_specific::shell::commands::popup::reposition(menu.id, positioner),
+            ]);
+        }
+        let id = window::Id::unique();
+        self.menu = Some(OpenMenu {
+            id,
+            kind,
+            motion: crate::motion::PopupMotion::new(self.config.animations),
+            effects: None,
+            regions: Default::default(),
+        });
         let action = cosmic::surface::action::app_popup::<Self>(
             |_| Default::default(),
             move |_| SctkPopupSettings {
@@ -79,23 +101,11 @@ impl FereseShell {
                 grab: true,
                 close_with_children: false,
                 input_zone: None,
-                positioner: SctkPositioner {
-                    anchor_rect: anchor,
-                    // Numeric protocol values avoid depending on libcosmic's private SCTK reexport.
-                    anchor: 2u32.try_into().unwrap(),  // bottom
-                    gravity: 6u32.try_into().unwrap(), // bottom-left
-                    offset: (anchor.width / 2, 8),
-                    size_limits: Limits::NONE
-                        .min_width(kind.width())
-                        .max_width(kind.width())
-                        .max_height(height_limit),
-                    constraint_adjustment: 3, // slide X/Y, never flip above the bar
-                    ..Default::default()
-                },
+                positioner: positioner.clone(),
             },
             Some(Box::new(Self::view_status_menu)),
         );
-        Task::batch([destroy, notifications]).chain(cosmic::task::message(cosmic::Action::Surface(action)))
+        notifications.chain(cosmic::task::message(cosmic::Action::Surface(action)))
     }
 
     pub fn destroy_menu(&mut self) -> Task<Message> {
@@ -136,7 +146,7 @@ impl FereseShell {
     pub fn animate_menu(&mut self) -> Task<Message> {
         if let Some(menu) = &self.menu {
             if let Some(effects) = &menu.effects {
-                let _ = effects.set_opacity(menu.progress());
+                let _ = effects.set_opacity(menu.progress().clamp(0.0, 1.0));
             }
             if menu.motion.closing() && !menu.animating() {
                 return self.destroy_menu();

shell/ferese-shell/src/system_modal.rs

@@ -295,7 +295,7 @@ impl FereseShell {
                 if let Some(effects) = &entry.effects {
                     let regions = entry.regions.lock().unwrap().clone();
                     let _ = effects.set_material_regions(&regions, ferese_surface_effects_v1::Role::Modal);
-                    let _ = effects.set_opacity(modal.motion.progress());
+                    let _ = effects.set_opacity(modal.motion.progress().clamp(0.0, 1.0));
                 }
             }
         }