Clean up shared UI runtime state

benches/message_list.rs

@@ -68,7 +68,12 @@ fn bench_first_frame(n: usize) {
     let start = Instant::now();
     render.update(&root, &mut rsc);
     let elapsed = start.elapsed();
-    let (draws, rewrites, moves, _shapes) = render.take_counters();
+    let RenderCounters {
+        draws,
+        region_rewrites: rewrites,
+        moves,
+        ..
+    } = render.take_counters();
     report(
         &format!("(a) first frame, N={n}"),
         elapsed,
@@ -97,7 +102,12 @@ fn bench_scroll(n: usize, ticks: usize) {
         let start = Instant::now();
         render.update(&root, &mut rsc);
         total += start.elapsed();
-        let (draws, rewrites, moves, _shapes) = render.take_counters();
+        let RenderCounters {
+            draws,
+            region_rewrites: rewrites,
+            moves,
+            ..
+        } = render.take_counters();
         total_draws += draws;
         total_rewrites += rewrites;
         total_moves += moves;
@@ -155,7 +165,12 @@ fn bench_input_grows(n: usize, lines: usize) {
         let start = Instant::now();
         render.update(&root, &mut rsc);
         total += start.elapsed();
-        let (draws, rewrites, moves, _shapes) = render.take_counters();
+        let RenderCounters {
+            draws,
+            region_rewrites: rewrites,
+            moves,
+            ..
+        } = render.take_counters();
         total_draws += draws;
         total_rewrites += rewrites;
         total_moves += moves;
@@ -200,7 +215,12 @@ fn bench_insert_above_anchor(n: usize, inserts: usize) {
         let start = Instant::now();
         render.update(&root, &mut rsc);
         total += start.elapsed();
-        let (draws, rewrites, moves, _shapes) = render.take_counters();
+        let RenderCounters {
+            draws,
+            region_rewrites: rewrites,
+            moves,
+            ..
+        } = render.take_counters();
         total_draws += draws;
         total_rewrites += rewrites;
         total_moves += moves;
@@ -270,7 +290,12 @@ fn bench_expand_holds_edge(n: usize, growths: usize) {
         let start = Instant::now();
         render.update(&root, &mut rsc);
         total += start.elapsed();
-        let (draws, rewrites, moves, _shapes) = render.take_counters();
+        let RenderCounters {
+            draws,
+            region_rewrites: rewrites,
+            moves,
+            ..
+        } = render.take_counters();
         total_draws += draws;
         total_rewrites += rewrites;
         total_moves += moves;
@@ -314,7 +339,12 @@ fn bench_redraw_big_text(chars: usize, redraws: usize) {
         render.update(&root, &mut rsc);
         total += start.elapsed();
     }
-    let (draws, rewrites, moves, _shapes) = render.take_counters();
+    let RenderCounters {
+        draws,
+        region_rewrites: rewrites,
+        moves,
+        ..
+    } = render.take_counters();
     report(
         &format!("(g) redraw one {chars}-glyph text, {redraws}x (totals)"),
         total,

core/src/ui/access.rs

@@ -32,7 +32,7 @@ fn entry_node(entry: &Entry) -> Node {
 /// Owns the last tree pushed out, so `update` can tell "nothing
 /// accessibility-relevant changed" from "something did" without asking
 /// the platform adapter to diff two `Node`s itself. One of these per
-/// window/view -- `default::DefaultUiState` and `android::AndroidUiState`
+/// window/view -- `desktop::DesktopUiState` and `android::AndroidUiState`
 /// each keep one.
 #[derive(Default)]
 pub struct AccessTree {

core/src/ui/render_state.rs

@@ -18,6 +18,14 @@ pub enum RedrawKind {
     Updates,
 }
 
+#[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
+pub struct RenderCounters {
+    pub draws: u64,
+    pub region_rewrites: u64,
+    pub moves: u64,
+    pub shapes: u64,
+}
+
 pub struct UiRenderState {
     pub active: HashMap<WidgetId, ActiveData>,
     pub primitives: Primitives,
@@ -115,13 +123,13 @@ impl UiRenderState {
         }
     }
 
-    pub fn take_counters(&mut self) -> (u64, u64, u64, u64) {
+    pub fn take_counters(&mut self) -> RenderCounters {
-        (
+        RenderCounters {
-            std::mem::take(&mut self.draw_count),
+            draws: std::mem::take(&mut self.draw_count),
-            std::mem::take(&mut self.region_mut_count),
+            region_rewrites: std::mem::take(&mut self.region_mut_count),
-            std::mem::take(&mut self.mov_count),
+            moves: std::mem::take(&mut self.mov_count),
-            std::mem::take(&mut self.shape_count),
+            shapes: std::mem::take(&mut self.shape_count),
-        )
+        }
     }
 
     pub(super) fn note_move(&mut self) {

examples/bench_images.rs

@@ -4,24 +4,24 @@ const ROWS: usize = 1000;
 const SETTLE_FRAMES: usize = 4;
 const FRAMES: usize = 6;
 
-#[derive(DefaultUiState)]
+#[derive(DesktopUiState)]
 struct State {
-    ui_state: DefaultUiState,
+    ui_state: DesktopUiState,
     span: WeakWidget<Span>,
     frame: usize,
     appended: bool,
 }
 
-impl DefaultAppState for State {
+impl DesktopAppState for State {
     fn new(
-        mut ui_state: DefaultUiState,
+        mut ui_state: DesktopUiState,
-        rsc: &mut DefaultRsc<Self>,
+        rsc: &mut DesktopRsc<Self>,
         _: Proxy<Self::Event>,
     ) -> Self {
         let mut span = Span::empty(Dir::DOWN);
         for _ in 0..ROWS {
             let img = image::DynamicImage::new_rgba8(32, 32);
-            let widget = image::<DefaultRsc<Self>>(img)(rsc);
+            let widget = image::<DesktopRsc<Self>>(img)(rsc);
             let widget = rsc.ui.widgets.add_strong(widget);
             span.push(widget.any());
         }
@@ -40,7 +40,7 @@ impl DefaultAppState for State {
         }
     }
 
-    fn window_event(&mut self, event: winit::event::WindowEvent, rsc: &mut DefaultRsc<Self>) {
+    fn window_event(&mut self, event: winit::event::WindowEvent, rsc: &mut DesktopRsc<Self>) {
         if !matches!(event, winit::event::WindowEvent::RedrawRequested) {
             return;
         }
@@ -53,7 +53,7 @@ impl DefaultAppState for State {
         if self.frame == SETTLE_FRAMES && !self.appended {
             self.appended = true;
             let img = image::DynamicImage::new_rgba8(32, 32);
-            let widget = image::<DefaultRsc<Self>>(img)(rsc);
+            let widget = image::<DesktopRsc<Self>>(img)(rsc);
             let widget = rsc.ui.widgets.add_strong(widget);
             rsc.ui
                 .widgets
@@ -71,5 +71,5 @@ impl DefaultAppState for State {
 }
 
 fn main() {
-    DefaultApp::<State>::run();
+    DesktopApp::<State>::run();
 }

examples/message_list.rs

@@ -2,12 +2,12 @@ use iris::prelude::*;
 use winit::{dpi::LogicalSize, window::WindowAttributes};
 
 fn main() {
-    DefaultApp::<State>::run();
+    DesktopApp::<State>::run();
 }
 
-#[derive(DefaultUiState)]
+#[derive(DesktopUiState)]
 struct State {
-    ui_state: DefaultUiState,
+    ui_state: DesktopUiState,
 }
 
 const ROWS: usize = 800;
@@ -58,14 +58,14 @@ fn build_row<Rsc: UiRsc + 'static>(rsc: &mut Rsc, i: usize) -> StrongWidget {
     }
 }
 
-impl DefaultAppState for State {
+impl DesktopAppState for State {
     fn window_attributes() -> WindowAttributes {
         WindowAttributes::default().with_inner_size(LogicalSize::new(420.0, 900.0))
     }
 
     fn new(
-        mut ui_state: DefaultUiState,
+        mut ui_state: DesktopUiState,
-        rsc: &mut DefaultRsc<Self>,
+        rsc: &mut DesktopRsc<Self>,
         _: Proxy<Self::Event>,
     ) -> Self {
         let mut list = LazySpan::new(Dir::DOWN, Pin::End);

examples/minimal.rs

@@ -1,18 +1,18 @@
 use iris::prelude::*;
 
 fn main() {
-    DefaultApp::<State>::run();
+    DesktopApp::<State>::run();
 }
 
-#[derive(DefaultUiState)]
+#[derive(DesktopUiState)]
 struct State {
-    ui_state: DefaultUiState,
+    ui_state: DesktopUiState,
 }
 
-impl DefaultAppState for State {
+impl DesktopAppState for State {
     fn new(
-        mut ui_state: DefaultUiState,
+        mut ui_state: DesktopUiState,
-        rsc: &mut DefaultRsc<Self>,
+        rsc: &mut DesktopRsc<Self>,
         _: Proxy<Self::Event>,
     ) -> Self {
         rect(PaintId::RED).set_root(rsc, &mut ui_state);

examples/tabs/main.rs

@@ -2,19 +2,19 @@ use iris::prelude::*;
 use winit::event::WindowEvent;
 
 fn main() {
-    DefaultApp::<Client>::run();
+    DesktopApp::<Client>::run();
 }
 
-#[derive(DefaultUiState)]
+#[derive(DesktopUiState)]
 pub struct Client {
-    ui_state: DefaultUiState,
+    ui_state: DesktopUiState,
     info: WeakWidget<Text>,
 }
 
-impl DefaultAppState for Client {
+impl DesktopAppState for Client {
     fn new(
-        mut ui_state: DefaultUiState,
+        mut ui_state: DesktopUiState,
-        rsc: &mut DefaultRsc<Self>,
+        rsc: &mut DesktopRsc<Self>,
         _: Proxy<Self::Event>,
     ) -> Self {
         let widgets = tabs_ui::build(rsc, &mut ui_state);
@@ -24,7 +24,7 @@ impl DefaultAppState for Client {
         }
     }
 
-    fn window_event(&mut self, _: WindowEvent, rsc: &mut DefaultRsc<Self>) {
+    fn window_event(&mut self, _: WindowEvent, rsc: &mut DesktopRsc<Self>) {
         let render_state = rsc.ui.render_state();
         let new = format!(
             "widgets: {}\nactive: {}\nviews: {}",

examples/task.rs

@@ -2,18 +2,18 @@ use iris::prelude::*;
 use std::time::Duration;
 
 fn main() {
-    DefaultApp::<State>::run();
+    DesktopApp::<State>::run();
 }
 
-#[derive(DefaultUiState)]
+#[derive(DesktopUiState)]
 struct State {
-    ui_state: DefaultUiState,
+    ui_state: DesktopUiState,
 }
 
-impl DefaultAppState for State {
+impl DesktopAppState for State {
     fn new(
-        mut ui_state: DefaultUiState,
+        mut ui_state: DesktopUiState,
-        rsc: &mut DefaultRsc<Self>,
+        rsc: &mut DesktopRsc<Self>,
         _: Proxy<Self::Event>,
     ) -> Self {
         let rect = rect(PaintId::RED).add(rsc);

examples/view.rs

@@ -1,15 +1,15 @@
 use iris::prelude::*;
 
 fn main() {
-    DefaultApp::<State>::run();
+    DesktopApp::<State>::run();
 }
 
-#[derive(DefaultUiState)]
+#[derive(DesktopUiState)]
 struct State {
-    ui_state: DefaultUiState,
+    ui_state: DesktopUiState,
 }
 
-type Rsc = DefaultRsc<State>;
+type Rsc = DesktopRsc<State>;
 
 #[derive(Clone, Copy, WidgetView)]
 struct Test {
@@ -35,10 +35,10 @@ impl Test {
     }
 }
 
-impl DefaultAppState for State {
+impl DesktopAppState for State {
     fn new(
-        mut ui_state: DefaultUiState,
+        mut ui_state: DesktopUiState,
-        rsc: &mut DefaultRsc<Self>,
+        rsc: &mut DesktopRsc<Self>,
         _: Proxy<Self::Event>,
     ) -> Self {
         let test = Test::new(rsc);

macro/src/lib.rs

@@ -101,8 +101,8 @@ pub fn widget_trait(input: TokenStream) -> TokenStream {
     .into()
 }
 
-#[proc_macro_derive(DefaultUiState, attributes(default_ui_state))]
+#[proc_macro_derive(DesktopUiState, attributes(desktop_ui_state))]
-pub fn derive_default_ui_state(input: TokenStream) -> TokenStream {
+pub fn derive_desktop_ui_state(input: TokenStream) -> TokenStream {
     let mut output = proc_macro2::TokenStream::new();
 
     let state: ItemStruct = parse_macro_input!(input);
@@ -112,14 +112,14 @@ pub fn derive_default_ui_state(input: TokenStream) -> TokenStream {
     for field in &state.fields {
         if !found_attr
             && let Type::Path(path) = &field.ty
-            && path.path.is_ident("DefaultUiState")
+            && path.path.is_ident("DesktopUiState")
         {
             state_field = Some(field);
         }
         let Some(attr) = field
             .attrs
             .iter()
-            .find(|a| a.path().is_ident("default_ui_state"))
+            .find(|a| a.path().is_ident("desktop_ui_state"))
         else {
             continue;
         };
@@ -127,7 +127,7 @@ pub fn derive_default_ui_state(input: TokenStream) -> TokenStream {
             output.extend(
                 Error::new(
                     attr.span(),
-                    "cannot have more than one default_ui_state attribute",
+                    "cannot have more than one desktop_ui_state attribute",
                 )
                 .into_compile_error(),
             );
@@ -138,18 +138,18 @@ pub fn derive_default_ui_state(input: TokenStream) -> TokenStream {
     }
     let Some(field) = state_field else {
         output.extend(
-            Error::new(state.ident.span(), "no DefaultUiState field found").into_compile_error(),
+            Error::new(state.ident.span(), "no DesktopUiState field found").into_compile_error(),
         );
         return output.into();
     };
     let sname = &state.ident;
     let fname = field.ident.as_ref().unwrap();
     output.extend(quote! {
-        impl iris::default::HasDefaultUiState for #sname {
+        impl iris::desktop::HasDesktopUiState for #sname {
-            fn default_state(&self) -> &iris::default::DefaultUiState {
+            fn desktop_state(&self) -> &iris::desktop::DesktopUiState {
                 &self.#fname
             }
-            fn default_state_mut(&mut self) -> &mut iris::default::DefaultUiState {
+            fn desktop_state_mut(&mut self) -> &mut iris::desktop::DesktopUiState {
                 &mut self.#fname
             }
         }

run-headless.sh

@@ -18,7 +18,7 @@
 # `content_scale` 2.55, from docs/bench/iris-phone-v2-2026-09-06.md,
 # carried in `ai_app::ui::fixture::PHONE_*`), and `IRIS_SCALE` hands that
 # density to iris the way `DisplayMetrics.density` does on Android
-# (`iris::default::content_scale`). So a screenshot from here and one
+# (`iris::desktop::content_scale`). So a screenshot from here and one
 # from the phone are the same layout at the same density, and what
 # differs is only the renderer. Without it the output stays desktop-
 # shaped, which is what every other example wants.

src/android/render.rs

@@ -176,7 +176,7 @@ impl AndroidRenderer {
             .filter(|part| !part.is_empty())
             .collect::<Vec<_>>()
             .join(" ");
-        // Say which adapter won, in the same words `default::render` uses,
+        // Say which adapter won, in the same words `desktop::render` uses,
         // and at startup rather than only on the Diagnostics page: the
         // backend alone (logged by `view.rs` when a renderer is built) does
         // not separate the cases that matter. In this checkout's emulator

src/android/view.rs

@@ -11,13 +11,7 @@ use android_view::{
     },
     ndk::event::{Axis, Keycode, MotionAction},
 };
-use std::{
+use std::{cell::RefCell, marker::Sized, rc::Rc, sync::Arc, time::Instant};
-    cell::RefCell,
-    marker::{PhantomData, Sized},
-    rc::Rc,
-    sync::Arc,
-    time::Instant,
-};
 
 use super::{
     access::{AndroidAccessSource, NullActionHandler, raise_if_enabled},
@@ -25,10 +19,7 @@ use super::{
     render::{AndroidRedrawHandle, AndroidRenderer},
 };
 
-/// The android-view analogue of `default::DefaultUiState`. `renderer` is an
+/// Android host state. The renderer follows the `SurfaceView` lifecycle.
-/// `Option` because a `SurfaceView`'s surface does not outlive backgrounding
-/// the way a winit `Window` does -- `surfaceDestroyed`/`surfaceCreated` can
-/// happen any number of times over the life of one `IrisViewPeer`.
 /// How many frames after each `surface_changed` `render()` logs a full
 /// diagnostic line for -- see the log site's own comment.
 const DIAGNOSTIC_FRAMES: u64 = 10;
@@ -39,24 +30,13 @@ pub struct AndroidUiState {
     pub focus: Option<WeakWidget<TextEdit>>,
     pub cursor: CursorState,
     pub last_click: Instant,
-    /// The IME preedit's previous length, in `char`s -- the same
+    /// Previous IME preedit length, in characters.
-    /// re-send-the-whole-composition bookkeeping `default::DefaultUiState`
-    /// keeps for winit's `Ime::Preedit`, since android-view's
-    /// `setComposingText` has the identical shape (see `android/ime.rs`).
     pub compose_len: usize,
-    /// Set by `attr::FocusHost::focus_gained` when a `TextEdit` is focused;
+    /// Deferred until the input callback regains access to JNI.
-    /// consumed by the touch handler after the sensor pass finishes, since
-    /// showing the keyboard is a JNI call and `focus_gained` runs deep
-    /// inside the platform-agnostic sensor dispatch with no `CallbackCtx`
-    /// in reach.
     pub pending_show_keyboard: bool,
-    /// A URL a tapped link asked the platform to open, for the same
+    /// Also deferred until a JNI callback is available.
-    /// reason `pending_show_keyboard` is a flag rather than a call --
-    /// see `android/platform.rs`.
     pub pending_open_url: Option<String>,
-    /// Window insets, filled in from outside the normal `ViewPeer` callback
+    /// Filled by the native insets callback registered in `android/insets.rs`.
-    /// path -- see `android/insets.rs` for why they need a registry of
-    /// their own.
     shared: Rc<RefCell<Shared>>,
     pub access_adapter: AccessAdapter,
     pub access: AccessTree,
@@ -132,13 +112,7 @@ pub trait AndroidAppState: HasAndroidUiState {
     fn on_insets_changed(&mut self, rsc: &mut AndroidRsc<Self>, insets: WindowInsets) {}
 }
 
-/// `insets::Insets` as `f32`, for the widget-facing callback above -- a
+/// Widget-facing insets in physical pixels, decoupled from JNI's integer shape.
-/// distinct type from `insets::Insets` so a caller of `on_insets_changed`
-/// is not coupled to that module's own (`i32`, JNI-shaped) representation.
-/// Both are physical pixels; this used to divide by `content_scale` into a
-/// separate *logical* unit (hence the old name, `LogicalInsets`), back when
-/// the rest of layout was logical too -- see `AndroidUiState::content_scale`'s
-/// field comment for why that stopgap is gone.
 #[derive(Clone, Copy, Default, Debug, PartialEq)]
 pub struct WindowInsets {
     pub left: f32,
@@ -166,66 +140,7 @@ impl WindowInsets {
     }
 }
 
-pub struct AndroidRsc<State: 'static> {
+pub type AndroidRsc<State> = AppRsc<State>;
-    pub ui: Ui,
-    pub events: EventManager<Self>,
-    pub tasks: Tasks<Self>,
-    pub state: WidgetState,
-    _state: PhantomData<State>,
-}
-
-impl<State> AndroidRsc<State> {
-    pub fn create_state<T: 'static>(&mut self, id: impl IdLike, data: T) -> WeakState<T> {
-        self.state.add(id.id(), data)
-    }
-}
-
-impl<State> UiRsc for AndroidRsc<State> {
-    fn ui(&self) -> &Ui {
-        &self.ui
-    }
-    fn ui_mut(&mut self) -> &mut Ui {
-        &mut self.ui
-    }
-    fn on_draw(&mut self, active: &ActiveData) {
-        self.events.draw(active);
-    }
-    fn on_undraw(&mut self, active: &ActiveData) {
-        self.events.undraw(active);
-    }
-    fn on_remove(&mut self, id: WidgetId) {
-        self.events.remove(id);
-        self.state.remove(id);
-    }
-}
-
-impl<State: 'static> HasState for AndroidRsc<State> {
-    type State = State;
-}
-
-impl<State: 'static> HasEvents for AndroidRsc<State> {
-    fn events(&self) -> &EventManager<Self> {
-        &self.events
-    }
-    fn events_mut(&mut self) -> &mut EventManager<Self> {
-        &mut self.events
-    }
-}
-
-impl<State: 'static> HasTasks for AndroidRsc<State> {
-    fn tasks_mut(&mut self) -> &mut Tasks<Self> {
-        &mut self.tasks
-    }
-}
-
-impl<State: 'static> HasWidgetState for AndroidRsc<State> {
-    fn widget_state(&self) -> &WidgetState {
-        &self.state
-    }
-    fn widget_state_mut(&mut self) -> &mut WidgetState {
-        &mut self.state
-    }
-}
 
 /// The `ViewPeer` android-view dispatches every callback to. One per
 /// `RustView` instance; `new_peer` (below) builds it and hands the id to
@@ -234,30 +149,10 @@ pub struct IrisViewPeer<State: AndroidAppState> {
     pub(super) rsc: AndroidRsc<State>,
     pub(super) state: State,
     task_recv: TaskMsgReceiver<AndroidRsc<State>>,
-    /// The one ruler this view dates everything on: touch samples in
+    /// Converts input and Choreographer timestamps onto one monotonic clock.
-    /// `on_touch_event` and the `Choreographer` frame time in `do_frame`.
-    /// Anchored by whichever of the two arrives first and never
-    /// re-anchored after, which is what lets a fling be advanced on the
-    /// same clock the gesture that launched it was measured on. Its path
-    /// out is the peer's own drop: it holds nothing but three numbers and
-    /// is meaningless to any other view.
     device_clock: Option<DeviceClock>,
 }
 
-impl<State: 'static, I: RscIdx<AndroidRsc<State>>> std::ops::Index<I> for AndroidRsc<State> {
-    type Output = I::Output;
-
-    fn index(&self, index: I) -> &Self::Output {
-        index.get(self)
-    }
-}
-
-impl<State: 'static, I: RscIdx<AndroidRsc<State>>> std::ops::IndexMut<I> for AndroidRsc<State> {
-    fn index_mut(&mut self, index: I) -> &mut Self::Output {
-        index.get_mut(self)
-    }
-}
-
 impl<State: AndroidAppState> IrisViewPeer<State> {
     fn drain_tasks(&mut self) {
         while let Ok(update) = self.task_recv.try_recv() {
@@ -298,7 +193,7 @@ impl<State: AndroidAppState> IrisViewPeer<State> {
     /// Common tail for every callback that might have changed the cursor,
     /// the text focus, or the widget tree: run the sensors that touch
     /// input feeds, then ask for a frame if the result needs drawing.
-    /// Mirrors `default::DefaultApp::window_event`'s tail, split across
+    /// Mirrors `desktop::DesktopApp::window_event`'s tail, split across
     /// android-view's several entry points instead of winit's one.
     pub(super) fn after_input(&mut self, ctx: &mut CallbackCtx) {
         self.run_input_frame(ctx);
@@ -322,6 +217,42 @@ impl<State: AndroidAppState> IrisViewPeer<State> {
             .get_or_insert_with(|| DeviceClock::anchored(Instant::now(), event_time, oldest))
     }
 
+    fn generic_motion(&mut self, ctx: &mut CallbackCtx, event: &MotionEvent<'_>) -> bool {
+        let action = event.action_masked(&mut ctx.env);
+        let event_time = event.event_time_nanos(&mut ctx.env);
+        let mut clock = self.device_clock(event_time, event_time);
+        let at = clock.sample(event_time);
+        self.device_clock = Some(clock);
+
+        let ui = self.state.android_state_mut();
+        ui.cursor.time = at;
+        ui.cursor.pos = vec2(event.x(&mut ctx.env), event.y(&mut ctx.env));
+        ui.cursor.exists = !matches!(action, MotionAction::HoverExit);
+
+        let buttons = event.button_state(&mut ctx.env);
+        ui.cursor.buttons.left.update(buttons.primary());
+        ui.cursor.buttons.right.update(buttons.secondary());
+        ui.cursor.buttons.middle.update(buttons.teriary());
+
+        match action {
+            MotionAction::HoverEnter
+            | MotionAction::HoverMove
+            | MotionAction::HoverExit
+            | MotionAction::ButtonPress
+            | MotionAction::ButtonRelease => {}
+            MotionAction::Scroll => {
+                ui.cursor.scroll_delta = vec2(
+                    event.axis(&mut ctx.env, Axis::Hscroll, 0),
+                    event.axis(&mut ctx.env, Axis::Vscroll, 0),
+                );
+            }
+            _ => return false,
+        }
+
+        self.after_input(ctx);
+        true
+    }
+
     fn window_size(&self) -> Vec2 {
         let ui_state = self.state.android_state();
         match &ui_state.renderer {
@@ -514,27 +445,14 @@ impl<State: AndroidAppState> ViewPeer for IrisViewPeer<State> {
     ) -> bool {
         self.drain_tasks();
         let action = event.action_masked(&mut ctx.env);
-        // Device (physical) pixels, same space layout now uses throughout
+        // MotionEvent and layout both use physical pixels.
-        // -- see `AndroidUiState::content_scale`'s field comment.
         let x = event.x(&mut ctx.env);
         let y = event.y(&mut ctx.env);
-        // The event's own clock, converted through the view's one anchor
+        // Use the event clock so batched movement keeps its real timing.
-        // -- taken on whichever of a touch or a frame callback came first.
-        // Android reports sample times in the `SystemClock.uptimeMillis()`
-        // base, which is the same `CLOCK_MONOTONIC` an `Instant` reads, so
-        // a single `(Instant, nanos)` pair converts every later sample
-        // exactly. Anchoring **once** rather than per event is what keeps
-        // the times ordered, and anchoring on the first event's *oldest*
-        // sample rather than on its own time is what keeps that event's
-        // batch from collapsing onto one instant -- `sense::DeviceClock`'s
-        // doc has both, and owns the arithmetic so it can be unit-tested
-        // off a device (`sense_tests.rs`). See `CursorState::time`.
         let event_time = event.event_time_nanos(&mut ctx.env);
         let history = event.history_size(&mut ctx.env);
         let mut clock = match self.device_clock {
             Some(clock) => clock,
-            // Only the call that anchors needs the batch's oldest sample,
-            // so the JNI read for it stays off the per-event path.
             None => {
                 let oldest = if history > 0 {
                     event.historical_event_time_nanos(&mut ctx.env, 0)
@@ -544,24 +462,12 @@ impl<State: AndroidAppState> ViewPeer for IrisViewPeer<State> {
                 self.device_clock(event_time, oldest)
             }
         };
-        // `iris::input`'s own doc (`sense::log_input_event`): collected
+        // Avoid allocating trace history when input tracing is disabled.
-        // only when tracing is on, since this is otherwise a `Vec` per
-        // `MotionEvent` for a line nobody is reading -- the JNI reads
-        // themselves (`historical_axis`/`historical_event_time_nanos`
-        // below) already happen unconditionally, for the replay this
-        // function does regardless of tracing.
         let trace_input = crate::diagnostics::trace_enabled();
         let mut historical_ms: Vec<(u64, f32, f32)> = Vec::new();
 
         if matches!(action, MotionAction::Move) {
-            // Android documents the historical samples as oldest first and
+            // Android orders history oldest-first; `sample` checks monotonicity.
-            // the event's own sample as the newest of the batch; everything
-            // downstream (`VelocityTracker`, `DragArbiter`'s long-press
-            // clock) assumes it, so say so here rather than at each reader.
-            // `DeviceClock::sample` is what asserts it, and it carries the
-            // last sample seen *across* events, so the first sample of
-            // every event is checked against the previous event's last one
-            // rather than against the anchor.
             for pos in 0..history {
                 let hx = event.historical_axis(&mut ctx.env, Axis::X, 0, pos);
                 let hy = event.historical_axis(&mut ctx.env, Axis::Y, 0, pos);
@@ -616,6 +522,38 @@ impl<State: AndroidAppState> ViewPeer for IrisViewPeer<State> {
         true
     }
 
+    fn on_generic_motion_event<'local>(
+        &mut self,
+        ctx: &mut CallbackCtx<'local>,
+        event: &MotionEvent<'local>,
+    ) -> bool {
+        self.drain_tasks();
+        self.generic_motion(ctx, event)
+    }
+
+    fn on_hover_event<'local>(
+        &mut self,
+        ctx: &mut CallbackCtx<'local>,
+        event: &MotionEvent<'local>,
+    ) -> bool {
+        let action = event.action(&mut ctx.env);
+        let x = event.x(&mut ctx.env);
+        let y = event.y(&mut ctx.env);
+        let ui = self.state.android_state_mut();
+        if let Some(events) = ui
+            .access_adapter
+            .on_hover_event(&mut NullActionHandler, action, x, y)
+        {
+            ctx.push_dynamic_deferred_callback(move |env, view| {
+                raise_if_enabled(env, view, events);
+            });
+            true
+        } else {
+            self.drain_tasks();
+            self.generic_motion(ctx, event)
+        }
+    }
+
     fn on_focus_changed<'local>(
         &mut self,
         ctx: &mut CallbackCtx<'local>,
@@ -646,32 +584,10 @@ impl<State: AndroidAppState> ViewPeer for IrisViewPeer<State> {
         height: i32,
     ) {
         self.drain_tasks();
-        // The layout engine's own notion of the canvas size is separate
+        // The layout canvas and wgpu surface are separate and both use physical pixels.
-        // from the wgpu surface's -- winit's backend sets it from
-        // `WindowEvent::Resized`, and there is no equivalent automatic
-        // trigger here, so this is the one place android-view's surface
-        // size has to be told to `UiRenderState` too. Missing this drew
-        // nothing but the clear colour: the widget tree laid out against
-        // whatever size `UiRenderState::new` starts at instead of the
-        // surface's real one.
-        //
-        // **Physical pixels, matching `AndroidRenderer`'s own
-        // `size()`/`resize()`/`new()`** -- `AndroidUiState::content_scale`'s
-        // field comment. This call sets `UiRenderState::output_size`, which
-        // every `rel`/`rest` length resolves against and every `abs`
-        // pixel-region compares to directly; a `dp(56)` height now folds
-        // in the density at `Len::apply_rest` time instead of this call
-        // dividing the whole window into a separate logical space, which
-        // is what used to make every `abs`-unit size (a fixed `.height(56)`
-        // in particular) mean something different from a `rest`-based one.
         self.rsc.ui.resize((width as f32, height as f32));
 
-        // `AndroidRenderer::resize` only reconfigures the wgpu surface and
+        // Resizing preserves GPU resources; recreating a destroyed surface does not.
-        // rewrites the window uniform -- device, atlas, buffers and bind
-        // groups are untouched, so the glyph cache's coordinates stay
-        // valid. A genuinely new surface (after `surface_destroyed`, e.g.
-        // backgrounding) still goes through `AndroidRenderer::new` below,
-        // since `renderer` is `None` in that case.
         let already_live = self.state.android_state().renderer.is_some();
         log::info!(
             "iris surface: surface_changed {width}x{height} already_live={already_live} \
@@ -883,14 +799,7 @@ pub fn new_peer<'local, State: AndroidAppState>(
     let vm = env.get_java_vm().unwrap();
     let global_view = env.new_global_ref(&view.0).unwrap();
     let redraw: Arc<dyn RequestRedraw> = Arc::new(AndroidRedrawHandle::new(vm, global_view));
-    let (tasks, task_recv) = Tasks::init(redraw);
+    let (mut rsc, task_recv) = AppRsc::new(redraw);
-    let mut rsc = AndroidRsc {
-        ui: Default::default(),
-        events: Default::default(),
-        tasks,
-        state: Default::default(),
-        _state: PhantomData,
-    };
     rsc.ui.set_density(content_scale);
     let shared = Rc::new(RefCell::new(Shared::default()));
     let ui_state = AndroidUiState::new(shared.clone(), content_scale);

src/desktop/attr.rs

@@ -1,21 +1,21 @@
 use crate::prelude::*;
 use winit::dpi::{PhysicalPosition, PhysicalSize};
 
-impl<T: HasDefaultUiState> FocusHost for T {
+impl<T: HasDesktopUiState> FocusHost for T {
     fn recent_click(&mut self) -> bool {
-        crate::attr::recent_click(&mut self.default_state_mut().last_click)
+        crate::attr::recent_click(&mut self.desktop_state_mut().last_click)
     }
 
     fn set_focus(&mut self, id: Option<WeakWidget<TextEdit>>) {
-        self.default_state_mut().focus = id;
+        self.desktop_state_mut().focus = id;
     }
 
     fn is_focused(&self, id: WeakWidget<TextEdit>) -> bool {
-        self.default_state().focus == Some(id)
+        self.desktop_state().focus == Some(id)
     }
 
     fn focus_gained(&mut self, region: Option<PixelRegion>) {
-        let state = self.default_state_mut();
+        let state = self.desktop_state_mut();
         let Some(region) = region else { return };
         state.window.set_ime_allowed(true);
         state.window.set_ime_cursor_area(

src/desktop/input.rs

@@ -19,7 +19,7 @@ pub struct Input {
 impl Input {
     /// winit's pointer coordinates are physical pixels, which is the
     /// space the whole tree is laid out and hit-tested in -- see
-    /// `default::content_scale`. Nothing is converted here; `dp(...)`
+    /// `desktop::content_scale`. Nothing is converted here; `dp(...)`
     /// resolves against the density at layout time instead.
     pub fn event(&mut self, event: &WindowEvent) -> bool {
         match event {
@@ -79,10 +79,10 @@ impl Input {
     }
 }
 
-impl DefaultUiState {
+impl DesktopUiState {
     /// Physical pixels, matching `WindowEvent::Resized` (what
     /// `UiRenderState::resize` is given) and the swapchain -- see
-    /// `default::content_scale`.
+    /// `desktop::content_scale`.
     pub fn window_size(&self) -> Vec2 {
         let size = self.renderer.window().inner_size();
         Vec2::new(size.width as f32, size.height as f32)

src/desktop/mod.rs

@@ -1,10 +1,6 @@
 use crate::prelude::*;
 use arboard::Clipboard;
-use std::{
+use std::{marker::Sized, sync::Arc, time::Instant};
-    marker::{PhantomData, Sized},
-    sync::Arc,
-    time::Instant,
-};
 use winit::{
     event::{Ime, WindowEvent},
     event_loop::{ActiveEventLoop, EventLoopProxy},
@@ -26,19 +22,8 @@ pub use render::*;
 
 pub type Proxy<Event> = EventLoopProxy<Event>;
 
-/// The desktop's `content_scale`: physical pixels per dp, the same
+/// Physical pixels per dp. Layout and input stay in physical pixels; only
-/// quantity Android reads from `DisplayMetrics.density` and feeds to
+/// `dp(...)` resolves through this scale.
-/// `UiRenderState::set_density` (`android::view::AndroidUiState::
-/// content_scale`'s field comment). Everything in this backend is
-/// physical pixels -- the window size, the pointer, the widget tree --
-/// and `dp(...)` is what resolves against this at layout time, exactly
-/// as on the phone. That is a correction from an earlier version that
-/// divided winit's coordinates into a separate "logical" space instead:
-/// it left `UiRenderState::resize` (physical, from `WindowEvent::
-/// Resized`) and the window uniform (logical) disagreeing on any
-/// display whose scale factor is not 1.0, and it rasterised glyphs at
-/// one resolution to display them at another -- the blur the phone's own
-/// stopgap produced before `dp` existed.
 pub fn content_scale(window: &Window) -> f32 {
     match std::env::var("IRIS_SCALE") {
         Err(_) => window.scale_factor() as f32,
@@ -52,7 +37,7 @@ pub fn content_scale(window: &Window) -> f32 {
     }
 }
 
-pub struct DefaultUiState {
+pub struct DesktopUiState {
     pub root: Option<StrongWidget>,
     pub renderer: UiRenderer,
     pub input: Input,
@@ -65,13 +50,13 @@ pub struct DefaultUiState {
     pub access: AccessTree,
 }
 
-impl<State: 'static> HasRoot<DefaultRsc<State>> for DefaultUiState {
+impl<State: 'static> HasRoot<DesktopRsc<State>> for DesktopUiState {
-    fn set_root(&mut self, rsc: &mut DefaultRsc<State>, root: StrongWidget) {
+    fn set_root(&mut self, rsc: &mut DesktopRsc<State>, root: StrongWidget) {
         self.root = Some(crate::overlay::default_overlay_root(rsc, root));
     }
 }
 
-impl DefaultUiState {
+impl DesktopUiState {
     pub fn new(window: impl Into<Arc<Window>>, access_adapter: accesskit_winit::Adapter) -> Self {
         let window = window.into();
         Self {
@@ -89,114 +74,35 @@ impl DefaultUiState {
     }
 }
 
-pub trait HasDefaultUiState: Sized + 'static {
+pub trait HasDesktopUiState: Sized + 'static {
-    fn default_state(&self) -> &DefaultUiState;
+    fn desktop_state(&self) -> &DesktopUiState;
-    fn default_state_mut(&mut self) -> &mut DefaultUiState;
+    fn desktop_state_mut(&mut self) -> &mut DesktopUiState;
 }
 
-pub trait DefaultAppState: HasDefaultUiState {
+pub trait DesktopAppState: HasDesktopUiState {
     type Event = ();
-    fn new(ui_state: DefaultUiState, rsc: &mut DefaultRsc<Self>, proxy: Proxy<Self::Event>)
+    fn new(ui_state: DesktopUiState, rsc: &mut DesktopRsc<Self>, proxy: Proxy<Self::Event>)
     -> Self;
     #[allow(unused_variables)]
-    fn event(&mut self, event: Self::Event, rsc: &mut DefaultRsc<Self>) {}
+    fn event(&mut self, event: Self::Event, rsc: &mut DesktopRsc<Self>) {}
     #[allow(unused_variables)]
-    fn exit(&mut self, rsc: &mut DefaultRsc<Self>) {}
+    fn exit(&mut self, rsc: &mut DesktopRsc<Self>) {}
     #[allow(unused_variables)]
-    fn window_event(&mut self, event: WindowEvent, rsc: &mut DefaultRsc<Self>) {}
+    fn window_event(&mut self, event: WindowEvent, rsc: &mut DesktopRsc<Self>) {}
     fn window_attributes() -> WindowAttributes {
         Default::default()
     }
 }
 
-pub struct DefaultRsc<State: 'static> {
+pub type DesktopRsc<State> = AppRsc<State>;
-    pub ui: Ui,
-    pub events: EventManager<Self>,
-    pub tasks: Tasks<Self>,
-    pub state: WidgetState,
-    _state: PhantomData<State>,
-}
 
-impl<State> DefaultRsc<State> {
+pub struct DesktopApp<State: DesktopAppState> {
-    fn init(window: Arc<Window>) -> (Self, TaskMsgReceiver<Self>) {
+    rsc: DesktopRsc<State>,
-        let (tasks, recv) = Tasks::init(window);
-        (
-            Self {
-                ui: Default::default(),
-                events: Default::default(),
-                tasks,
-                state: Default::default(),
-                _state: Default::default(),
-            },
-            recv,
-        )
-    }
-
-    pub fn create_state<T: 'static>(&mut self, id: impl IdLike, data: T) -> WeakState<T> {
-        self.state.add(id.id(), data)
-    }
-}
-
-impl<State> UiRsc for DefaultRsc<State> {
-    fn ui(&self) -> &Ui {
-        &self.ui
-    }
-
-    fn ui_mut(&mut self) -> &mut Ui {
-        &mut self.ui
-    }
-
-    fn on_draw(&mut self, active: &ActiveData) {
-        self.events.draw(active);
-    }
-
-    fn on_undraw(&mut self, active: &ActiveData) {
-        self.events.undraw(active);
-    }
-
-    fn on_remove(&mut self, id: WidgetId) {
-        self.events.remove(id);
-        self.state.remove(id);
-    }
-}
-
-impl<State: 'static> HasState for DefaultRsc<State> {
-    type State = State;
-}
-
-impl<State: 'static> HasEvents for DefaultRsc<State> {
-    fn events(&self) -> &EventManager<Self> {
-        &self.events
-    }
-
-    fn events_mut(&mut self) -> &mut EventManager<Self> {
-        &mut self.events
-    }
-}
-
-impl<State: 'static> HasTasks for DefaultRsc<State> {
-    fn tasks_mut(&mut self) -> &mut Tasks<Self> {
-        &mut self.tasks
-    }
-}
-
-impl<State: 'static> HasWidgetState for DefaultRsc<State> {
-    fn widget_state(&self) -> &WidgetState {
-        &self.state
-    }
-
-    fn widget_state_mut(&mut self) -> &mut WidgetState {
-        &mut self.state
-    }
-}
-
-pub struct DefaultApp<State: DefaultAppState> {
-    rsc: DefaultRsc<State>,
     state: State,
-    task_recv: TaskMsgReceiver<DefaultRsc<State>>,
+    task_recv: TaskMsgReceiver<DesktopRsc<State>>,
 }
 
-impl<State: DefaultAppState> AppState for DefaultApp<State> {
+impl<State: DesktopAppState> AppState for DesktopApp<State> {
     type Event = State::Event;
 
     fn new(event_loop: &ActiveEventLoop, proxy: EventLoopProxy<Self::Event>) -> Self {
@@ -211,16 +117,12 @@ impl<State: DefaultAppState> AppState for DefaultApp<State> {
             NullDeactivationHandler,
         );
         window.set_visible(true);
-        let default_state = DefaultUiState::new(window, access_adapter);
+        let desktop_state = DesktopUiState::new(window, access_adapter);
-        let (mut rsc, task_recv) = DefaultRsc::init(default_state.window.clone());
+        let (mut rsc, task_recv) = AppRsc::new(desktop_state.window.clone());
-        // Both copies of the density, set before the first widget is
+        // Set before building widgets so the first text shape uses the right density.
-        // built so text shapes at the right size on the opening frame --
+        let scale = content_scale(desktop_state.window.as_ref());
-        // the same pair `android::view::new_peer` sets from
-        // `content_scale`. See `iris_core::TextData::density` for why the
-        // shaper keeps its own.
-        let scale = content_scale(default_state.window.as_ref());
         rsc.ui.set_density(scale);
-        let state = State::new(default_state, &mut rsc, proxy);
+        let state = State::new(desktop_state, &mut rsc, proxy);
         Self {
             rsc,
             state,
@@ -243,7 +145,7 @@ impl<State: DefaultAppState> AppState for DefaultApp<State> {
             update(state, rsc);
         }
 
-        let ui_state = state.default_state_mut();
+        let ui_state = state.desktop_state_mut();
         // Required by `accesskit_winit` on every window event, not just the
         // ones this backend otherwise cares about -- some platform adapters
         // rely on it to notice activation (a screen reader turning on).
@@ -257,14 +159,7 @@ impl<State: DefaultAppState> AppState for DefaultApp<State> {
             ui_state.focus = None;
         }
         if input_changed {
-            // The winit half of `iris::input` (`sense::log_input_event`'s
+            // Winit delivers one sample at a time, so there is no history batch.
-            // own doc): no batching here, so `historical` is always empty
-            // -- winit hands one `WindowEvent` per pointer sample, unlike
-            // Android's `MotionEvent`. The action is read back off the
-            // buttons `Input::event` just updated, the same test
-            // `GestureOutcome`'s callers already use to tell a press from a
-            // release. Computed only when tracing is on, same reasoning as
-            // `log_input_event` itself gating on it.
             if crate::diagnostics::trace_enabled() {
                 let action = if cursor_state.buttons.left.is_start() {
                     "down"
@@ -292,7 +187,7 @@ impl<State: DefaultAppState> AppState for DefaultApp<State> {
                 .get()
                 .run_sensors(rsc, state, cursor_state, window_size);
         }
-        let ui_state = state.default_state_mut();
+        let ui_state = state.desktop_state_mut();
         if old != ui_state.focus
             && let Some(old) = old
         {
@@ -301,16 +196,10 @@ impl<State: DefaultAppState> AppState for DefaultApp<State> {
         match &event {
             WindowEvent::CloseRequested => event_loop.exit(),
             WindowEvent::RedrawRequested => {
-                // Before the draw, so this frame shows this instant's
+                // Advance animations before drawing and keep requesting frames while active.
-                // position (`UiData::tick_animations`' own doc), and the
-                // window is asked for another frame while anything is
-                // still moving -- the winit half of what
-                // `IrisViewPeer::render`'s `post_frame_callback` does on
-                // Android. Nothing else in iris moves without an input
-                // event.
                 let frame_start = std::time::Instant::now();
                 let animating = rsc.ui_mut().tick_animations(frame_start);
-                let ui_state = state.default_state_mut();
+                let ui_state = state.desktop_state_mut();
                 if animating {
                     ui_state.window.request_redraw();
                 }
@@ -415,7 +304,7 @@ impl<State: DefaultAppState> AppState for DefaultApp<State> {
             _ => (),
         }
         state.window_event(event, rsc);
-        let ui_state = self.state.default_state_mut();
+        let ui_state = self.state.desktop_state_mut();
         let render_state = rsc.ui.render_state();
         if render_state
             .get()
@@ -430,17 +319,3 @@ impl<State: DefaultAppState> AppState for DefaultApp<State> {
         self.state.exit(&mut self.rsc);
     }
 }
-
-impl<State: 'static, I: RscIdx<DefaultRsc<State>>> std::ops::Index<I> for DefaultRsc<State> {
-    type Output = I::Output;
-
-    fn index(&self, index: I) -> &Self::Output {
-        index.get(self)
-    }
-}
-
-impl<State: 'static, I: RscIdx<DefaultRsc<State>>> std::ops::IndexMut<I> for DefaultRsc<State> {
-    fn index_mut(&mut self, index: I) -> &mut Self::Output {
-        index.get_mut(self)
-    }
-}

src/desktop/platform.rs

@@ -1,7 +1,7 @@
 use crate::platform::OpenUrl;
-use crate::prelude::HasDefaultUiState;
+use crate::prelude::HasDesktopUiState;
 
-impl<T: HasDefaultUiState> OpenUrl for T {
+impl<T: HasDesktopUiState> OpenUrl for T {
     fn open_url(&mut self, url: &str) {
         let (program, first): (&str, &[&str]) = if cfg!(target_os = "macos") {
             ("open", &[])

src/desktop/render.rs

@@ -213,7 +213,7 @@ impl UiRenderer {
         // that function's doc comment).
         // Physical size, the same units the swapchain, `WindowEvent::
         // Resized`, the pointer and the widget tree all use -- see
-        // `default::content_scale` for why this backend stopped dividing
+        // `desktop::content_scale` for why this backend stopped dividing
         // into a separate logical space, and what disagreed while it did.
         let physical_size = Vec2::new(size.width as f32, size.height as f32);
         let ui = UiRenderNode::new(&device, &queue, formats.view, physical_size)

src/diagnostics.rs

@@ -15,7 +15,7 @@ pub fn trace_enabled() -> bool {
 
 /// One `iris::frame` line, called once per frame from each backend's own
 /// frame function -- `android::view::IrisViewPeer::render`,
-/// `default::DefaultApp::window_event`'s `RedrawRequested` arm, and
+/// `desktop::DesktopApp::window_event`'s `RedrawRequested` arm, and
 /// `harness::Harness::frame` -- after the draw (or, on the harness, where a
 /// draw would be; `draw` is `Duration::ZERO` there since nothing is
 /// actually submitted to a GPU).

src/harness.rs

@@ -1,5 +1,4 @@
 use crate::prelude::*;
-use std::marker::PhantomData;
 use std::sync::Arc;
 use std::sync::atomic::{AtomicUsize, Ordering};
 use std::time::{Duration, Instant};
@@ -164,76 +163,7 @@ impl OpenUrl for HarnessState {
     }
 }
 
-/// The harness's `Rsc` -- identical in substance to `DefaultRsc`/
+pub type HarnessRsc = AppRsc<HarnessState>;
-/// `AndroidRsc` minus the windowing, for the same reason those two are
-/// separate types (`AndroidRsc`'s own doc).
-pub struct HarnessRsc {
-    pub ui: Ui,
-    pub events: EventManager<Self>,
-    pub tasks: Tasks<Self>,
-    pub state: WidgetState,
-    _state: PhantomData<HarnessState>,
-}
-
-impl UiRsc for HarnessRsc {
-    fn ui(&self) -> &Ui {
-        &self.ui
-    }
-    fn ui_mut(&mut self) -> &mut Ui {
-        &mut self.ui
-    }
-    fn on_draw(&mut self, active: &ActiveData) {
-        self.events.draw(active);
-    }
-    fn on_undraw(&mut self, active: &ActiveData) {
-        self.events.undraw(active);
-    }
-    fn on_remove(&mut self, id: WidgetId) {
-        self.events.remove(id);
-        self.state.remove(id);
-    }
-}
-
-impl HasState for HarnessRsc {
-    type State = HarnessState;
-}
-
-impl HasEvents for HarnessRsc {
-    fn events(&self) -> &EventManager<Self> {
-        &self.events
-    }
-    fn events_mut(&mut self) -> &mut EventManager<Self> {
-        &mut self.events
-    }
-}
-
-impl HasTasks for HarnessRsc {
-    fn tasks_mut(&mut self) -> &mut Tasks<Self> {
-        &mut self.tasks
-    }
-}
-
-impl HasWidgetState for HarnessRsc {
-    fn widget_state(&self) -> &WidgetState {
-        &self.state
-    }
-    fn widget_state_mut(&mut self) -> &mut WidgetState {
-        &mut self.state
-    }
-}
-
-impl<I: RscIdx<HarnessRsc>> std::ops::Index<I> for HarnessRsc {
-    type Output = I::Output;
-    fn index(&self, index: I) -> &Self::Output {
-        index.get(self)
-    }
-}
-
-impl<I: RscIdx<HarnessRsc>> std::ops::IndexMut<I> for HarnessRsc {
-    fn index_mut(&mut self, index: I) -> &mut Self::Output {
-        index.get_mut(self)
-    }
-}
 
 /// A screen running with no window: the widget tree, the frame loop and
 /// the pointer, all advanced by the caller. See the module doc.
@@ -255,14 +185,7 @@ impl Harness {
     /// `PHONE_SCALE`.
     pub fn new(size: Vec2, density: f32) -> Self {
         let redraws = Arc::new(RedrawCounter::default());
-        let (tasks, task_recv) = Tasks::init(redraws.clone());
+        let (mut rsc, task_recv) = AppRsc::new(redraws.clone());
-        let mut rsc = HarnessRsc {
-            ui: Ui::default(),
-            events: EventManager::default(),
-            tasks,
-            state: WidgetState::default(),
-            _state: PhantomData,
-        };
         rsc.ui.set_density(density);
         rsc.ui.resize(size);
         Self {

src/layout_tests.rs

@@ -115,7 +115,7 @@ fn a_widget_retains_its_entry_layer_not_its_child_cursor() {
     rsc.ui.widgets.get_mut(&outer_weak).unwrap().x = None;
     render.update(&root, &mut rsc);
     assert_eq!(
-        render.take_counters().0,
+        render.take_counters().draws,
         1,
         "redrawing the parent should retain the unchanged Stack subtree"
     );
@@ -250,7 +250,12 @@ fn a_child_coordinate_offset_moves_only_the_child_subtree() {
     rsc.ui.widgets.get_mut(&parent_weak).unwrap().offset.y = 35.0;
     rsc.ui.widgets.get_mut(&outer_weak).unwrap().x = None;
     render.update(&root, &mut rsc);
-    let (draws, rewrites, moves, _shapes) = render.take_counters();
+    let RenderCounters {
+        draws,
+        region_rewrites: rewrites,
+        moves,
+        ..
+    } = render.take_counters();
     let parent_after = render.window_region(&parent_weak, &rsc).unwrap();
     let child_after = render.window_region(&child_weak, &rsc).unwrap();
 
@@ -283,7 +288,7 @@ fn a_hinted_rest_draws_once_and_only_moves_the_fixed_child_after_it() {
     let mut render = UiRenderState::new();
     render.resize((200.0, 300.0));
     render.update(&root, &mut rsc);
-    let (draws, _rewrites, moves, _shapes) = render.take_counters();
+    let RenderCounters { draws, moves, .. } = render.take_counters();
 
     assert_eq!(draws, 5);
     assert_eq!(moves, 1);
@@ -328,7 +333,12 @@ fn an_unchanged_frame_draws_and_rewrites_nothing() {
     render.take_counters(); // discard the first, real draws
 
     render.update(&root, &mut rsc);
-    let (draws, rewrites, moves, _shapes) = render.take_counters();
+    let RenderCounters {
+        draws,
+        region_rewrites: rewrites,
+        moves,
+        ..
+    } = render.take_counters();
     assert_eq!((draws, rewrites, moves), (0, 0, 0));
 }
 
@@ -346,7 +356,7 @@ fn scrolling_moves_in_o1_without_a_redraw() {
 
     rsc.ui.widgets.get_mut(&scroll).unwrap().scroll(-40.0);
     render.update(&root, &mut rsc);
-    let (draws, _rewrites, moves, _shapes) = render.take_counters();
+    let RenderCounters { draws, moves, .. } = render.take_counters();
 
     assert_eq!(draws, 1, "only Scroll itself should redraw");
     assert_eq!(moves, 1, "the scrolled subtree should move in one write");

src/lib.rs

@@ -1,6 +1,6 @@
 #![feature(unboxed_closures)]
 #![feature(fn_traits)]
-// Only `default::DefaultAppState::Event`'s default uses this; unused (and
+// Only `desktop::DesktopAppState::Event`'s default uses this; unused (and
 // warned about) on the android target, which has no such default.
 #![cfg_attr(not(target_os = "android"), feature(associated_type_defaults))]
 #![feature(unsize)]
@@ -10,7 +10,7 @@
 #[cfg(target_os = "android")]
 pub mod android;
 #[cfg(not(target_os = "android"))]
-pub mod default;
+pub mod desktop;
 
 pub mod attr;
 pub mod diagnostics;
@@ -18,6 +18,7 @@ pub mod event;
 pub mod harness;
 pub mod overlay;
 pub mod platform;
+pub mod runtime;
 pub mod sense;
 pub mod state;
 pub mod task;
@@ -38,7 +39,7 @@ pub mod prelude {
     #[cfg(target_os = "android")]
     pub use android::*;
     #[cfg(not(target_os = "android"))]
-    pub use default::*;
+    pub use desktop::*;
 
     pub use attr::*;
     pub use event::*;
@@ -46,6 +47,7 @@ pub mod prelude {
     pub use iris_macro::*;
     pub use overlay::*;
     pub use platform::*;
+    pub use runtime::*;
     pub use sense::*;
     pub use state::*;
     pub use task::*;

src/runtime.rs

@@ -0,0 +1,98 @@
+use crate::prelude::*;
+use std::sync::Arc;
+
+/// Resources shared by every Iris host.
+pub struct AppRsc<State: 'static> {
+    pub ui: Ui,
+    pub events: EventManager<Self>,
+    pub tasks: Tasks<Self>,
+    pub state: WidgetState,
+    _state: std::marker::PhantomData<State>,
+}
+
+impl<State> AppRsc<State> {
+    pub(crate) fn new(redraw: Arc<dyn RequestRedraw>) -> (Self, TaskMsgReceiver<Self>) {
+        let (tasks, receiver) = Tasks::init(redraw);
+        (
+            Self {
+                ui: Ui::default(),
+                events: EventManager::default(),
+                tasks,
+                state: WidgetState::default(),
+                _state: std::marker::PhantomData,
+            },
+            receiver,
+        )
+    }
+
+    pub fn create_state<T: 'static>(&mut self, id: impl IdLike, data: T) -> WeakState<T> {
+        self.state.add(id.id(), data)
+    }
+}
+
+impl<State> UiRsc for AppRsc<State> {
+    fn ui(&self) -> &Ui {
+        &self.ui
+    }
+
+    fn ui_mut(&mut self) -> &mut Ui {
+        &mut self.ui
+    }
+
+    fn on_draw(&mut self, active: &ActiveData) {
+        self.events.draw(active);
+    }
+
+    fn on_undraw(&mut self, active: &ActiveData) {
+        self.events.undraw(active);
+    }
+
+    fn on_remove(&mut self, id: WidgetId) {
+        self.events.remove(id);
+        self.state.remove(id);
+    }
+}
+
+impl<State> HasState for AppRsc<State> {
+    type State = State;
+}
+
+impl<State> HasEvents for AppRsc<State> {
+    fn events(&self) -> &EventManager<Self> {
+        &self.events
+    }
+
+    fn events_mut(&mut self) -> &mut EventManager<Self> {
+        &mut self.events
+    }
+}
+
+impl<State> HasTasks for AppRsc<State> {
+    fn tasks_mut(&mut self) -> &mut Tasks<Self> {
+        &mut self.tasks
+    }
+}
+
+impl<State> HasWidgetState for AppRsc<State> {
+    fn widget_state(&self) -> &WidgetState {
+        &self.state
+    }
+
+    fn widget_state_mut(&mut self) -> &mut WidgetState {
+        &mut self.state
+    }
+}
+
+impl<State, I: RscIdx<AppRsc<State>>> std::ops::Index<I> for AppRsc<State> {
+    type Output = I::Output;
+
+    fn index(&self, index: I) -> &Self::Output {
+        index.get(self)
+    }
+}
+
+impl<State, I: RscIdx<AppRsc<State>>> std::ops::IndexMut<I> for AppRsc<State> {
+    fn index_mut(&mut self, index: I) -> &mut Self::Output {
+        index.get_mut(self)
+    }
+}

src/widget/position/lazy_span.rs

@@ -1155,7 +1155,7 @@ mod tests {
                 .push_front(LazyItem::new(key, w));
         }
         render.update(&root, &mut rsc);
-        let (draws, _rewrites, _moves, _shapes) = render.take_counters();
+        let draws = render.take_counters().draws;
 
         let extents_after = rsc.ui.widgets.get(&list_weak).unwrap().extents.clone();
         for key in [11u64, 12] {
@@ -1269,7 +1269,8 @@ mod tests {
 
             rsc.ui.widgets.get_mut(&list_weak).unwrap().scroll(1.0);
             render.update(&root, &mut rsc);
-            let (draws, _rewrites, moves, _shapes) = render.take_counters();
+            let counters = render.take_counters();
+            let (draws, moves) = (counters.draws, counters.moves);
 
             assert_eq!(draws, 1, "n={n}: only the list should really draw");
             assert_eq!(moves, 1, "n={n}: the whole retained run should move once");