Run planned multiphase layout animations

src/animation.rs

@@ -131,6 +131,7 @@ pub struct AnimationState {
     pub duration_ms: Cell<u32>,
     pub curve: Cell<AnimationCurve>,
     windows: RefCell<AHashMap<NodeId, WindowAnimation>>,
+    phased: RefCell<AHashMap<NodeId, PhasedWindowAnimation>>,
     exits: RefCell<Vec<ExitAnimation>>,
     tick: CloneCell<Option<Rc<AnimationTick>>>,
 }
@@ -263,6 +264,7 @@ impl Default for AnimationState {
             duration_ms: Cell::new(DEFAULT_DURATION_MS),
             curve: Cell::new(AnimationCurve::from_config(3)),
             windows: Default::default(),
+            phased: Default::default(),
             exits: Default::default(),
             tick: Default::default(),
         }
@@ -272,6 +274,7 @@ impl Default for AnimationState {
 impl AnimationState {
     pub fn clear(&self) {
         self.windows.borrow_mut().clear();
+        self.phased.borrow_mut().clear();
         self.exits.borrow_mut().clear();
         if let Some(tick) = self.tick.take() {
             tick.detach();
@@ -290,20 +293,39 @@ impl AnimationState {
     ) -> bool {
         if old == new || old.is_empty() || new.is_empty() || duration_ms == 0 {
             self.windows.borrow_mut().remove(&node_id);
+            self.phased.borrow_mut().remove(&node_id);
             return false;
         }
         let duration_nsec = duration_ms as u64 * 1_000_000;
-        let mut windows = self.windows.borrow_mut();
-        let (from, retained) = match windows.get(&node_id) {
-            Some(anim) if anim.to == new => return false,
-            Some(anim) => (anim.rect_at(now_nsec), anim.retained.clone().or(retained)),
-            None => (old, retained),
-        };
+        let mut from = old;
+        let mut retained = retained;
+        {
+            let phased = self.phased.borrow();
+            if let Some(anim) = phased.get(&node_id) {
+                if anim.final_rect == new {
+                    return false;
+                }
+                from = anim.rect_at(now_nsec);
+                retained = anim.retained.clone().or(retained);
+            }
+        }
+        {
+            let windows = self.windows.borrow();
+            if let Some(anim) = windows.get(&node_id) {
+                if anim.to == new {
+                    return false;
+                }
+                from = anim.rect_at(now_nsec);
+                retained = anim.retained.clone().or(retained);
+            }
+        }
         if from == new {
-            windows.remove(&node_id);
+            self.windows.borrow_mut().remove(&node_id);
+            self.phased.borrow_mut().remove(&node_id);
             return false;
         }
-        windows.insert(
+        self.phased.borrow_mut().remove(&node_id);
+        self.windows.borrow_mut().insert(
             node_id,
             WindowAnimation {
                 from,
@@ -318,6 +340,47 @@ impl AnimationState {
         true
     }
 
+    pub fn set_phased_target(
+        &self,
+        node_id: NodeId,
+        phases: Vec<(Rect, Rect)>,
+        retained: Option<Rc<RetainedToplevel>>,
+        now_nsec: u64,
+        duration_ms: u32,
+        curve: AnimationCurve,
+    ) -> bool {
+        if phases.is_empty() || duration_ms == 0 {
+            return false;
+        }
+        let Some((from, _)) = phases.first().copied() else {
+            return false;
+        };
+        let Some((_, final_rect)) = phases.last().copied() else {
+            return false;
+        };
+        if from.is_empty() || final_rect.is_empty() || from == final_rect {
+            return false;
+        }
+        let segments: Vec<_> = phases
+            .into_iter()
+            .map(|(from, to)| PhasedSegment { from, to })
+            .collect();
+        self.windows.borrow_mut().remove(&node_id);
+        self.phased.borrow_mut().insert(
+            node_id,
+            PhasedWindowAnimation {
+                segments,
+                start_nsec: now_nsec,
+                duration_nsec: duration_ms as u64 * 1_000_000,
+                curve,
+                last_damage: from,
+                final_rect,
+                retained,
+            },
+        );
+        true
+    }
+
     pub fn set_spawn_in(
         &self,
         node_id: NodeId,
@@ -375,6 +438,13 @@ impl AnimationState {
     }
 
     pub fn visual_rect(&self, node_id: NodeId, layout: Rect, now_nsec: u64) -> Rect {
+        let phased = self.phased.borrow();
+        if let Some(anim) = phased.get(&node_id)
+            && !anim.done(now_nsec)
+        {
+            return anim.rect_at(now_nsec);
+        }
+        drop(phased);
         let windows = self.windows.borrow();
         match windows.get(&node_id) {
             Some(anim) if !anim.done(now_nsec) => anim.rect_at(now_nsec),
@@ -387,6 +457,13 @@ impl AnimationState {
         node_id: NodeId,
         now_nsec: u64,
     ) -> Option<Rc<RetainedToplevel>> {
+        let phased = self.phased.borrow();
+        if let Some(anim) = phased.get(&node_id)
+            && !anim.done(now_nsec)
+        {
+            return anim.retained.clone();
+        }
+        drop(phased);
         let windows = self.windows.borrow();
         match windows.get(&node_id) {
             Some(anim) if !anim.done(now_nsec) => anim.retained.clone(),
@@ -427,6 +504,18 @@ impl AnimationState {
                 any_active |= active;
                 active
             });
+            self.phased.borrow_mut().retain(|_, anim| {
+                let current = anim.rect_at(now_nsec);
+                let damage = anim.last_damage.union(current).union(anim.final_rect);
+                damages.push(expand_damage_rect(
+                    damage,
+                    state.theme.sizes.border_width.get().max(0),
+                ));
+                anim.last_damage = current;
+                let active = !anim.done(now_nsec);
+                any_active |= active;
+                active
+            });
             self.exits.borrow_mut().retain_mut(|exit| {
                 let current = exit.rect_at(now_nsec);
                 let damage = exit.last_damage.union(current).union(exit.to);
@@ -485,6 +574,45 @@ impl WindowAnimation {
     }
 }
 
+struct PhasedWindowAnimation {
+    segments: Vec<PhasedSegment>,
+    start_nsec: u64,
+    duration_nsec: u64,
+    curve: AnimationCurve,
+    last_damage: Rect,
+    final_rect: Rect,
+    retained: Option<Rc<RetainedToplevel>>,
+}
+
+struct PhasedSegment {
+    from: Rect,
+    to: Rect,
+}
+
+impl PhasedWindowAnimation {
+    fn done(&self, now_nsec: u64) -> bool {
+        let total_duration = self
+            .duration_nsec
+            .saturating_mul(self.segments.len() as u64);
+        now_nsec.saturating_sub(self.start_nsec) >= total_duration
+    }
+
+    fn rect_at(&self, now_nsec: u64) -> Rect {
+        if self.duration_nsec == 0 {
+            return self.final_rect;
+        }
+        let elapsed = now_nsec.saturating_sub(self.start_nsec);
+        let phase = (elapsed / self.duration_nsec) as usize;
+        let Some(segment) = self.segments.get(phase) else {
+            return self.final_rect;
+        };
+        let phase_elapsed = elapsed % self.duration_nsec;
+        let t = (phase_elapsed as f64 / self.duration_nsec as f64).clamp(0.0, 1.0);
+        let t = self.curve.sample(t);
+        lerp_rect(segment.from, segment.to, t)
+    }
+}
+
 struct ExitAnimation {
     from: Rect,
     to: Rect,
@@ -722,6 +850,53 @@ mod tests {
         assert!(state.exit_frames(160_000_000).is_empty());
     }
 
+    #[test]
+    fn phased_animation_uses_full_duration_per_phase() {
+        let state = AnimationState::default();
+        let id = NodeId(1);
+        let a = Rect::new_sized_saturating(0, 0, 100, 100);
+        let b = Rect::new_sized_saturating(0, 0, 100, 50);
+        let c = Rect::new_sized_saturating(100, 0, 100, 50);
+        assert!(state.set_phased_target(
+            id,
+            vec![(a, b), (b, c)],
+            None,
+            0,
+            100,
+            AnimationCurve::Linear
+        ));
+        assert_eq!(state.visual_rect(id, c, 0), a);
+        assert_eq!(state.visual_rect(id, c, 50_000_000), lerp_rect(a, b, 0.5));
+        assert_eq!(state.visual_rect(id, c, 100_000_000), b);
+        assert_eq!(state.visual_rect(id, c, 150_000_000), lerp_rect(b, c, 0.5));
+        assert_eq!(state.visual_rect(id, c, 200_000_000), c);
+    }
+
+    #[test]
+    fn linear_retarget_interrupts_phased_animation_from_current_rect() {
+        let state = AnimationState::default();
+        let id = NodeId(1);
+        let a = Rect::new_sized_saturating(0, 0, 100, 100);
+        let b = Rect::new_sized_saturating(0, 0, 100, 50);
+        let c = Rect::new_sized_saturating(100, 0, 100, 50);
+        let d = Rect::new_sized_saturating(100, 100, 100, 50);
+        assert!(state.set_phased_target(
+            id,
+            vec![(a, b), (b, c)],
+            None,
+            0,
+            100,
+            AnimationCurve::Linear
+        ));
+        let current = lerp_rect(a, b, 0.5);
+        assert!(state.set_target(id, a, d, None, 50_000_000, 100, AnimationCurve::Linear));
+        assert_eq!(state.visual_rect(id, d, 50_000_000), current);
+        assert_eq!(
+            state.visual_rect(id, d, 100_000_000),
+            lerp_rect(current, d, 0.5)
+        );
+    }
+
     #[test]
     fn unchanged_target_does_not_restart() {
         let state = AnimationState::default();

src/state.rs

@@ -4,7 +4,9 @@ use {
         allocator::BufferObject,
         animation::{
             AnimationCurve, AnimationState, AnimationTick, RetainedExitLayer, RetainedToplevel,
-            expand_damage_rect, spawn_in_start_rect,
+            expand_damage_rect,
+            multiphase::{MultiphaseRequest, MultiphaseWindow, plan_no_overlap},
+            spawn_in_start_rect,
         },
         async_engine::{AsyncEngine, SpawnedFuture},
         backend::{
@@ -157,6 +159,7 @@ use {
     uapi::{OwnedFd, c},
 };
 
+#[derive(Clone)]
 pub(crate) struct LayoutAnimationCandidate {
     node_id: NodeId,
     old: Rect,
@@ -1583,11 +1586,98 @@ impl State {
             return;
         };
         let now = self.now_nsec();
+        if self.start_multiphase_layout_animation(&candidates, now) {
+            return;
+        }
         for candidate in candidates {
             self.start_layout_animation_candidate(candidate, now);
         }
     }
 
+    fn start_multiphase_layout_animation(
+        self: &Rc<Self>,
+        candidates: &[LayoutAnimationCandidate],
+        now_nsec: u64,
+    ) -> bool {
+        if candidates.len() < 2 {
+            return false;
+        }
+        let windows: Vec<_> = candidates
+            .iter()
+            .map(|candidate| MultiphaseWindow {
+                node_id: candidate.node_id,
+                from: self
+                    .animations
+                    .visual_rect(candidate.node_id, candidate.old, now_nsec),
+                to: candidate.new,
+            })
+            .collect();
+        let Some(first) = windows.first() else {
+            return false;
+        };
+        let mut bounds = first.from.union(first.to);
+        for window in &windows[1..] {
+            bounds = bounds.union(window.from).union(window.to);
+        }
+        let Ok(plan) = plan_no_overlap(&MultiphaseRequest { bounds, windows }) else {
+            return false;
+        };
+        if plan.phases.is_empty() {
+            return false;
+        }
+        let mut entries = vec![];
+        for candidate in candidates {
+            let mut current =
+                self.animations
+                    .visual_rect(candidate.node_id, candidate.old, now_nsec);
+            let mut damage = current.union(candidate.new);
+            let mut phases = vec![];
+            for phase in &plan.phases {
+                match phase
+                    .steps
+                    .iter()
+                    .find(|step| step.node_id == candidate.node_id)
+                {
+                    Some(step) => {
+                        phases.push((step.from, step.to));
+                        damage = damage.union(step.from).union(step.to);
+                        current = step.to;
+                    }
+                    None => phases.push((current, current)),
+                }
+            }
+            if current != candidate.new {
+                return false;
+            }
+            let retained = self
+                .animations
+                .retained_snapshot(candidate.node_id, now_nsec)
+                .or_else(|| candidate.retained.clone());
+            entries.push((candidate.clone(), phases, damage, retained));
+        }
+        let mut started_any = false;
+        for (candidate, phases, damage, retained) in entries {
+            if self.animations.set_phased_target(
+                candidate.node_id,
+                phases,
+                retained,
+                now_nsec,
+                self.animations.duration_ms.get(),
+                candidate.curve,
+            ) {
+                started_any = true;
+                self.damage(expand_damage_rect(
+                    damage,
+                    self.theme.sizes.border_width.get().max(0),
+                ));
+            }
+        }
+        if started_any {
+            self.ensure_animation_tick();
+        }
+        started_any
+    }
+
     pub fn queue_spawn_in_animation(
         self: &Rc<Self>,
         node_id: NodeId,