Add spawn-in window animations

docs/window-animations-plan.md

@@ -12,8 +12,10 @@ be handled deliberately.
 - Pointer drag and resize initiated by the mouse or tablet do not animate.
 - Linear animations restart only for windows whose destination changes. Other
   in-flight windows keep their existing timelines.
-- Spawn-in uses scale and position. Spawn-out requires retained visual content
-  and is deferred until the freezing layer exists.
+- Spawn-in uses scale and position for newly mapped tiled and floating app
+  windows. Layer-shell, overlay, override-redirect, and fullscreen surfaces do
+  not use this path. Spawn-out requires retained visual content after the live
+  node is gone and remains deferred.
 - Command-driven tile-to-float and float-to-tile transitions may animate.
   Protocol drag/drop paths do not.
 - The no-overlap multiphase system is a separate phase after the linear path is
@@ -80,8 +82,8 @@ Implementation shape:
 Initial scope:
 
 - Tiled reflow animation.
-- Floating command-driven moves, tile-to-float, float-to-tile, and spawn-in are
-  deferred until after tiled reflow is validated.
+- Floating command-driven moves, tile-to-float, and float-to-tile are deferred
+  until after tiled reflow and spawn-in are validated.
 - Cross-output and cross-scale movements snap for now.
 - Linear mode may overlap windows during swaps. That is expected for the classic
   interpolation mode; no-overlap is Phase 3.
@@ -89,7 +91,6 @@ Initial scope:
   deferred, but animated windows must still be clipped to their presentation
   bounds and must preserve the existing stretch behavior for undersized contents.
 - No spawn-out.
-- No content freezing.
 - No multiphase no-overlap planner.
 
 Tests:
@@ -107,6 +108,8 @@ Goal: freeze visual contents during movement and enable spawn-out.
 Initial retained-record implementation status:
 
 - Tiled animation can retain GPU/dmabuf-backed XDG and Xwayland surface trees.
+- Spawn-in animation can retain GPU/dmabuf-backed XDG and Xwayland surface trees
+  for both tiled windows and floating child contents.
 - Retained records hold both `GfxTexture` and `SurfaceBuffer` references so the
   existing buffer release/sync path remains authoritative.
 - Single-pixel buffers can be retained as color records.

src/animation.rs

@@ -17,6 +17,8 @@ use {
 };
 
 const DEFAULT_DURATION_MS: u32 = 160;
+const SPAWN_IN_INITIAL_SCALE_NUMERATOR: i32 = 4;
+const SPAWN_IN_INITIAL_SCALE_DENOMINATOR: i32 = 5;
 
 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
 pub enum AnimationCurve {
@@ -224,6 +226,26 @@ impl AnimationState {
         true
     }
 
+    pub fn set_spawn_in(
+        &self,
+        node_id: NodeId,
+        target: Rect,
+        retained: Option<Rc<RetainedToplevel>>,
+        now_nsec: u64,
+        duration_ms: u32,
+    ) -> bool {
+        let start = spawn_in_start_rect(target);
+        self.set_target(
+            node_id,
+            start,
+            target,
+            retained,
+            now_nsec,
+            duration_ms,
+            AnimationCurve::Linear,
+        )
+    }
+
     pub fn visual_rect(&self, node_id: NodeId, layout: Rect, now_nsec: u64) -> Rect {
         let windows = self.windows.borrow();
         match windows.get(&node_id) {
@@ -350,6 +372,23 @@ impl LatchListener for AnimationTick {
     }
 }
 
+pub(crate) fn spawn_in_start_rect(target: Rect) -> Rect {
+    fn scaled_dimension(value: i32) -> i32 {
+        let scaled = (value as i64 * SPAWN_IN_INITIAL_SCALE_NUMERATOR as i64
+            / SPAWN_IN_INITIAL_SCALE_DENOMINATOR as i64) as i32;
+        scaled.clamp(1, value.max(1))
+    }
+
+    let width = scaled_dimension(target.width());
+    let height = scaled_dimension(target.height());
+    Rect::new_sized_saturating(
+        target.x1() + (target.width() - width) / 2,
+        target.y1() + (target.height() - height) / 2,
+        width,
+        height,
+    )
+}
+
 fn lerp_rect(from: Rect, to: Rect, t: f64) -> Rect {
     fn lerp(from: i32, to: i32, t: f64) -> i32 {
         (from as f64 + (to as f64 - from as f64) * t).round() as i32
@@ -437,4 +476,25 @@ mod tests {
             Rect::new_sized_saturating(125, 0, 100, 100)
         );
     }
+
+    #[test]
+    fn spawn_in_start_rect_is_centered_and_non_empty() {
+        let target = Rect::new_sized_saturating(10, 20, 100, 50);
+        assert_eq!(
+            spawn_in_start_rect(target),
+            Rect::new_sized_saturating(20, 25, 80, 40)
+        );
+    }
+
+    #[test]
+    fn spawn_in_uses_linear_curve() {
+        let state = AnimationState::default();
+        let id = NodeId(1);
+        let target = Rect::new_sized_saturating(10, 20, 100, 50);
+        assert!(state.set_spawn_in(id, target, None, 0, 160));
+        assert_eq!(
+            state.visual_rect(id, target, 80_000_000),
+            Rect::new_sized_saturating(15, 23, 90, 45)
+        );
+    }
 }

src/renderer.rs

@@ -15,7 +15,7 @@ use {
         state::State,
         theme::{Color, CornerRadius},
         tree::{
-            ContainerNode, DisplayNode, FloatNode, OutputNode, PlaceholderNode, ToplevelData,
+            ContainerNode, DisplayNode, FloatNode, Node, OutputNode, PlaceholderNode, ToplevelData,
             ToplevelNode, ToplevelNodeBase, WorkspaceNode, tab_bar::TabBar,
         },
     },
@@ -207,8 +207,13 @@ impl Renderer<'_> {
                     if stacked.node_visible() {
                         self.base.sync();
                         let pos = stacked.node_absolute_position();
-                        if pos.intersects(&opos) {
-                            let (x, y) = opos.translate(pos.x1(), pos.y1());
+                        let visual = self.state.animations.visual_rect(
+                            stacked.node_id(),
+                            pos,
+                            self.state.now_nsec(),
+                        );
+                        if visual.intersects(&opos) {
+                            let (x, y) = opos.translate(visual.x1(), visual.y1());
                             stacked.node_render(self, x, y, None);
                         }
                     }
@@ -983,6 +988,10 @@ impl Renderer<'_> {
             _ => return,
         };
         let pos = floating.position.get();
+        let visual =
+            self.state
+                .animations
+                .visual_rect(floating.node_id(), pos, self.state.now_nsec());
         let theme = &self.state.theme;
         let bw = theme.sizes.border_width.get();
         let bc = if floating.active.get() {
@@ -991,16 +1000,26 @@ impl Renderer<'_> {
             theme.colors.border.get()
         };
         let cr = theme.corner_radius.get();
-        let outer = Rect::new_sized_saturating(0, 0, pos.width(), pos.height());
+        let outer = Rect::new_sized_saturating(0, 0, visual.width(), visual.height());
         self.render_rounded_frame(outer, &bc, cr, bw, x, y);
-        let body =
-            Rect::new_sized_saturating(x + bw, y + bw, pos.width() - 2 * bw, pos.height() - 2 * bw);
+        let body = Rect::new_sized_saturating(
+            x + bw,
+            y + bw,
+            visual.width() - 2 * bw,
+            visual.height() - 2 * bw,
+        );
         let scissor_body = self.base.scale_rect(body);
+        self.stretch = if pos.width() != visual.width() || pos.height() != visual.height() {
+            Some(self.base.scale_point(body.width(), body.height()))
+        } else {
+            None
+        };
         if !cr.is_zero() {
             let inner_cr = self.scale_corner_radius(cr.expanded_by(-(bw as f32)));
             self.corner_radius = Some(inner_cr);
         }
-        child.node_render(self, body.x1(), body.y1(), Some(&scissor_body));
+        self.render_child_or_snapshot(&child, body.x1(), body.y1(), Some(&scissor_body));
+        self.stretch = None;
         self.corner_radius = None;
     }
 

src/state.rs

@@ -4,6 +4,7 @@ use {
         allocator::BufferObject,
         animation::{
             AnimationCurve, AnimationState, AnimationTick, RetainedToplevel, expand_damage_rect,
+            spawn_in_start_rect,
         },
         async_engine::{AsyncEngine, SpawnedFuture},
         backend::{
@@ -1516,6 +1517,33 @@ impl State {
         }
     }
 
+    pub fn queue_spawn_in_animation(
+        self: &Rc<Self>,
+        node_id: NodeId,
+        target: Rect,
+        retained: Option<Rc<RetainedToplevel>>,
+    ) {
+        if !self.animations.enabled.get() || target.is_empty() {
+            return;
+        }
+        let start = spawn_in_start_rect(target);
+        let now = self.now_nsec();
+        let started = self.animations.set_spawn_in(
+            node_id,
+            target,
+            retained,
+            now,
+            self.animations.duration_ms.get(),
+        );
+        if started {
+            self.damage(expand_damage_rect(
+                start.union(target),
+                self.theme.sizes.border_width.get().max(0),
+            ));
+            self.ensure_animation_tick();
+        }
+    }
+
     pub fn set_animations_enabled(&self, enabled: bool) {
         if self.animations.enabled.replace(enabled) && !enabled {
             self.animations.clear();

src/tree/float.rs

@@ -153,6 +153,14 @@ impl FloatNode {
             _ => return,
         };
         let pos = self.position.get();
+        let spawn_in_pending = {
+            let data = child.tl_data();
+            data.spawn_in_pending.get() && data.kind.is_app_window() && !data.is_fullscreen.get()
+        };
+        if spawn_in_pending && self.visible.get() {
+            self.state
+                .queue_spawn_in_animation(self.id.into(), pos, None);
+        }
         let theme = &self.state.theme;
         let bw = theme.sizes.border_width.get();
         let cpos = Rect::new_sized_saturating(

src/tree/toplevel.rs

@@ -118,6 +118,7 @@ impl<T: ToplevelNodeBase> ToplevelNode for T {
         let parent_was_none = data.parent.set(Some(parent.clone())).is_none();
         if parent_was_none {
             data.mapped_during_iteration.set(data.state.eng.iteration());
+            data.spawn_in_pending.set(data.kind.is_app_window());
             data.property_changed(TL_CHANGED_NEW);
         }
         let was_floating = data.parent_is_float.get();
@@ -185,6 +186,7 @@ impl<T: ToplevelNodeBase> ToplevelNode for T {
     fn tl_change_extents(self: Rc<Self>, rect: &Rect) {
         let data = self.tl_data();
         let prev = data.desired_extents.replace(*rect);
+        let spawn_in_pending = data.spawn_in_pending.get();
         let parent_is_mono = data
             .parent
             .get()
@@ -205,6 +207,22 @@ impl<T: ToplevelNodeBase> ToplevelNode for T {
                 self.tl_animation_snapshot(),
             );
         }
+        if spawn_in_pending
+            && !rect.is_empty()
+            && data.visible.get()
+            && !data.is_fullscreen.get()
+            && data.kind.is_app_window()
+            && !self.node_is_container()
+        {
+            data.state.clone().queue_spawn_in_animation(
+                data.node_id,
+                *rect,
+                self.tl_animation_snapshot(),
+            );
+        }
+        if spawn_in_pending && !rect.is_empty() {
+            data.spawn_in_pending.set(false);
+        }
         if prev.size() != rect.size() {
             for sc in data.jay_screencasts.lock().values() {
                 sc.schedule_realloc_or_reconfigure();
@@ -403,6 +421,13 @@ impl ToplevelType {
             ToplevelType::XWindow { .. } => window::X_WINDOW,
         }
     }
+
+    pub fn is_app_window(&self) -> bool {
+        matches!(
+            self,
+            ToplevelType::XdgToplevel(_) | ToplevelType::XWindow(_)
+        )
+    }
 }
 
 pub struct ToplevelData {
@@ -425,6 +450,7 @@ pub struct ToplevelData {
     pub title: RefCell<String>,
     pub parent: CloneCell<Option<Rc<dyn ContainingNode>>>,
     pub mapped_during_iteration: Cell<u64>,
+    pub spawn_in_pending: Cell<bool>,
     pub pos: Cell<Rect>,
     pub desired_extents: Cell<Rect>,
     pub seat_state: NodeSeatState,
@@ -488,6 +514,7 @@ impl ToplevelData {
             title: RefCell::new(title),
             parent: Default::default(),
             mapped_during_iteration: Cell::new(0),
+            spawn_in_pending: Cell::new(false),
             pos: Default::default(),
             desired_extents: Default::default(),
             seat_state: Default::default(),