Struct TileHost 

pub struct TileHost {
    pub focused: bool,
    /* private fields */
}

Fields

focused: bool

Implementations

impl TileHost

pub fn window_search(&self, doc: &AutoCommit) -> WindowPublication

What this tile’s app publishes for the search of its window: what its host reads through its widgets, or what an app keeping its own document says it publishes (AppWidget::window_search).

impl TileHost

pub fn content_shift(&self) -> f64

How far the content is drawn from where it was laid out (Self::offset_layout): what its app placed at x shows at x + content_shift().

pub fn take_host_intent(&mut self) -> Option<AppHostIntent>

pub fn mount_component( component: AppComponent, sink: impl Fn(WakeEvent) + Send + Sync + 'static, ) -> Result<TileHost, LaunchError>

Bind a prepared component’s wake lifetime before mounting it in a group. Setup failure retains the component’s record and recovery reports.

pub fn from_component(component: AppComponent) -> TileHost

pub fn set_window_presents_history(&mut self, tab_presents: bool)

A desktop window hosts this tile; tab_presents says whether the window’s tab row shows (and so presents the History control). The tile then never draws a History band of its own: closed, History is opened from the tab row, or from the app’s header row while the tab row is hidden.

pub fn queue_control( &mut self, invocation: ControlInvocation, ) -> Result<(), ControlInvocation>

Queue invocation as one of the hosted app’s own controls: an action the person chose over this window (its in-app search) runs inside the app, under the app’s custody and permissions, exactly as clicking the control in it would. The outer document never resolves an app’s actions by address, so this is the only way such a choice reaches the app.

pub fn visit_search_root( &mut self, visit: &mut dyn FnMut(&mut dyn Widget) -> bool, ) -> Option<bool>

Run visit on the root of this tile’s app, where the window’s search finds a document or a list (crate::widget::WindowSearch); visit says whether it changed what the app shows. None for a tile with no app (a placeholder, a notice).

pub fn in_place_search(&mut self) -> InPlace

What the window’s search can act on in this tile’s app.

pub fn register_document_history( &mut self, definition: &'static HistoryDefinition, ) -> Result<(), HistoryRegistrationError>

pub fn new(content: TileContent) -> TileHost

pub fn asking_for_input(&self) -> bool

Whether the app in this tile is asking the person to type: a text field of it holds the keyboard (Widget::ime_content). A stub, a notice, a window whose code is on its way, or another device’s page asks nothing.

pub fn with_arrival_shape(self, shape: SkeletonShape) -> TileHost

What the app whose code is on its way declared its window shows meanwhile (crate::widget::SkeletonShape): the shape the app’s manifest declares, read from the registry before its code is in. A tile told nothing shows its ground alone, as a window that declared no shape does.

pub fn arriving_from(self, from: Source) -> TileHost

Content whose first frame comes from from: an TileContent::Arriving place for an app whose code a host serves.

pub fn arrival_step(&self, now: Instant) -> Option<Step>

The placeholder step standing in the tile at now, while one does: the content’s first frame is not shown yet.

pub fn is_arriving(&self) -> bool

Whether the tile still stands for content whose first frame is not shown: its placeholder (or the ground it reserves) is what is there.

pub fn holds_first_frame_until(&self, now: Instant) -> Option<Instant>

Until when the window’s first frame waits for this tile’s content: a first frame from this device, inside its frame budget.

pub fn set_panic_scope(&self, tab: u64)

Name tab to a panic hook while this tile’s application runs: see panic_scope.

pub fn set_hosted_window(&mut self, window: HostedWindow)

Show this tile’s app in window: while the app runs, its crate::window_toolbar calls act on window, where the host reads its slots for the window’s bar and hands back what the person did with them (crate::window_slots::WindowSlots). For a host that runs several apps in its own process and draws their bars.

pub fn hosted_window(&self) -> Option<&HostedWindow>

The window this tile’s app is shown in, if the host gave it one.

pub fn take_place_of(&mut self, next: TileHost)

Stand where this tile stands from now on: next, built for the same window (an app whose code or record arrived where a placeholder held its place), goes on with the arrival (Self::continue_arrival) and takes this tile’s retained layout node: the app is laid out under that node in place and the rest of the host’s tree is kept, unless a History around it is busy.

pub fn continue_arrival(&mut self, previous: &TileHost)

Built in place of previous (an app whose code or record just arrived, in the window that reserved its place): while previous still stood for content not shown, this host goes on with that arrival, so its placeholder keeps its timing and the app cross-fades in over it instead of the window cutting or starting over.

pub fn record_transition_error(&self) -> Option<&str>

pub fn kind_string(&self) -> String

pub fn app_mut(&mut self) -> Option<&mut (dyn AppWidget + 'static)>

The hosted app, to reach a capability or concrete type of it in place. Unlike replacing the content, this leaves the tile’s record, History and layout alone: a change inside the app reports its own structure.

pub fn replace_component( &mut self, component: AppComponent, ) -> Vec<ComponentCloseReport>

Replace a component after its complete closed-owner cleanup. The caller retains returned reports until recovery is durably resolved.

pub fn replace_content(&mut self, content: TileContent)

Used when a window announced before it existed (a place reserved for it) becomes the app; replacing the tab instead would hand focus elsewhere. Flags a structural rebuild since App and the card variants have different taffy shapes.

pub fn content(&self) -> &TileContent

pub fn set_focused(&mut self, focused: bool)

pub fn start_spawn_animation(&mut self)

A call mid-animation restarts the curve.

pub fn spawn_in_flight(&self) -> bool

pub fn complete_content_rect(&self) -> Option<Rect>

Desktop-space card rect for an app-provided complete semantic canvas. The provider reports tile-content size; the shell card grows from the live tile’s top-left and never shrinks below the live window surface.

pub fn draw_complete_content_capture( &mut self, scene: &mut Scene, transform: Affine, tr: &mut TextRenderer, theme: &Theme, presence: &PresenceCtx, ) -> Option<Rect>

Paint a complete app-provided canvas in the ordinary window card. The app owns only its semantic pixels; shared clipping, corner radius and focus edge remain toolkit code, exactly as on screen.

impl TileHost

pub fn set_square_bottom(&mut self, square: bool)

The tile’s bottom edge is the display’s: square its lower corners.

impl TileHost

pub fn hold_content( &mut self, tr: &mut TextRenderer, theme: &Theme, presence: &PresenceCtx, )

Hold this window still as it is now, under the hold hold_windows began: from here on it draws what it draws now, wherever it moves, until release_windows. Without a hold, or already held under this one, nothing changes.

pub fn content_held(&self) -> bool

Whether this window is held still under the hold in place.

impl TileHost

pub fn history_control(&self) -> Option<HistoryControl>

The History control the window’s tab row shows for this tile: open or closed, or None where the tile has no History to open.

pub fn invoke_history_control( &mut self, control: HistoryControl, ) -> Result<(), String>

Press the window’s History control for this tile: open History, or close it while it shows, through the same History door the History shortcut and the palette use.

Errors

The tile has no History, or its door refused the operation.

Trait Implementations

impl ActionControls for TileHost

fn install_control_custody( &mut self, domain: &ControlDomain, attachment: CustodyAttachment, )

Bind retained producers before their first callback. Private holders must override this; child traversal alone never certifies full coverage.

fn take_control_invocation(&mut self) -> Option<ControlInvocation>

Drain one queued action-bound control intent from this subtree.

fn refresh_control_action_availability( &mut self, allowed: &HashSet<ActionAddress>, )

Push the fresh local permission-filtered action surface into every retained control: refresh this widget’s own emitter, then its children.

fn take_attributed_control_invocation( &mut self, ) -> Option<(ControlInvocation, Option<InvocationId>)>

Self::take_control_invocation, with the effect invocation the intent continues when an effect’s handler or completion queued it: the host applies it for that invocation’s invoker.

fn on_control_invocation_result( &mut self, address: &ActionAddress, result: &Result<ResourceOperationStart, DoorError>, )

Report the admission result of one queued local control invocation. Accepted means queued, not completed; confirmation remains an error while the host offers its normal confirmation UI. This notification grants no document authority and must not retry the invocation itself.

fn control_action_bindings(&self) -> Vec<ControlBindingMetadata>

Inventory action-native and explicitly legacy controls. A widget that owns an emitter prepends its metadata to its descendants’ inventory.

fn action_control_bindings(&self) -> Vec<ControlBindingMetadata>

Action-emitter bindings in the same order and exposure as the full inventory. Custom private inventories keep their authoritative default; wrappers can avoid allocating semantic-only accessibility snapshots.

fn has_action_control_bindings(&self) -> bool

Whether this exposed subtree contains controls consuming action availability. An override must match whether control_action_bindings contains an Action, including the same modal child exposure, regardless of current availability.

fn has_pending_control_invocation(&self) -> bool

Local control intent queued behind asynchronous startup preparation. A scheduling hint only; the host still checks live authority.

impl AudiencePresentationProvider for TileHost

fn audience_presentation_request(&self) -> Option<AudiencePresentationRequest>

Request a real audience toplevel on a different output.

fn on_audience_presentation_changed(&mut self, active: bool)

Report whether the audience toplevel is currently live.

fn draw_audience_presentation( &mut self, scene: &mut Scene, transform: Affine, text_renderer: &mut TextRenderer, theme: &Theme, rect: Rect, ) -> bool

Paint the audience-only projection of the app’s existing state.

fn handle_audience_presentation_event( &mut self, event: &WindowEvent, state: &mut Edits<'_>, path: &ExId, ) -> bool

Route controls originating on the audience surface.

fn on_audience_presentation_closed(&mut self)

Treat closing the audience toplevel as an explicit stop request.

impl CollaborationTopology for TileHost

fn collaboration_children_mut(&mut self) -> Vec<&mut dyn Widget>

impl ComponentLifecycle for TileHost

fn unsaved_documents(&self, doc: &AutoCommit) -> Vec<UnsavedDocument>

App-declared external document obligations. An in-memory record set is not evidence that an editable file has been saved.

fn checkpoint_components(&mut self) -> Vec<String>

Non-destructive persistence checkpoint. Never closes a wake scope or removes a tree; a failed host close must leave every child usable.

fn finish_admitted_close(&mut self) -> Vec<ComponentCloseReport>

Only the host may call this after every checkpoint succeeded, without dispatching another document mutation in between.

fn close_components(&mut self) -> Vec<ComponentCloseReport>

Capture and close nested components before removing their live trees, transferring all recovery reports to the caller.

fn take_component_close_reports(&mut self) -> Vec<ComponentCloseReport>

Drain inert close-report ownership once; never invoke ordinary app callbacks through a closed component.

fn on_window_close_requested(&mut self) -> WindowCloseAdmission

Admit or defer the primary native window’s ordinary close request. Roots that defer must later produce a one-shot close intent.

fn take_window_close_intent(&mut self) -> bool

One-shot approval after an earlier deferred ordinary window close.

fn take_replacement(&mut self) -> Option<ComponentReplacement>

The component this root’s own component asked to show in its place (AppComponent::take_replacement), for the host that mounted it. A component nested deeper answers to the host that mounted it, so the default reaches no child.

fn take_save_status_presentation(&mut self) -> bool

One-shot: the durability of this root’s own component’s record changed since this was last asked, and the root already synced with the new state. A host that asks (an App) presents it with a frame of its own, not a rebuilt tree; one that does not ask sees it through take_structure_dirty.

impl Continuable for TileHost

fn continuation_metadata( &self, state: &AutoCommit, path: &ExId, ) -> Option<ContinuationMetadata>

Return a compact, path-free projection of state that may be resumed on another device owned by the same person.

fn restore_continuation_metadata( &mut self, metadata: &ContinuationMetadata, state: &mut Edits<'_>, path: &ExId, ) -> bool

Apply a continuation projection after launch. Implementations must not change focus or start media; malformed or unknown metadata is ignored.

fn restore_live_continuation_metadata( &mut self, metadata: &ContinuationMetadata, state: &AutoCommit, path: &ExId, ) -> bool

Apply a live owner view to an already-bound resource. This opt-in capability receives no writable document and must preserve focus. Missing resources or anchors are refused so the host can defer or cancel the projection when its authenticated source disappears.

impl FloatingSurfaceProvider for TileHost

fn on_floating_surface_focus_changed(&mut self, id: Option<&str>, focused: bool)

Route native keyboard focus to the exact presentation instance.

fn on_floating_surface_ime_source_changed(&mut self, id: Option<&str>)

Keep the exact secondary presentation’s editor logically focused while the platform deliberately retains text-input focus on its source. A host-authenticated input route, not a claim by the app; the host clears it when the continuation ends or no longer validates.

fn on_floating_surface_event_source(&mut self, id: Option<&str>)

Identify the native surface delivering the current input event. The host resets this immediately after dispatch; it grants no authority.

fn floating_surface_event( &mut self, id: &str, event: &WindowEvent, ctx: &mut EventCtx<'_>, ) -> bool

Deliver one input event aimed at the card id, in the desk’s coordinates: the frame the card’s hits were recorded in. Answers whether the card took the event.

fn floating_surface_accessibility(&self, id: &str) -> Option<AccessNode>

The retained semantic subtree presented in one secondary window.

fn perform_floating_surface_accessibility_action( &mut self, id: &str, target: &str, action: &Action, state: &mut Edits<'_>, path: &ExId, ) -> bool

fn floating_surface_ime(&self, id: &str) -> Option<(InputContent, Rect)>

IME content type and desktop-logical caret rect for one secondary window.

fn take_floating_surface_request(&mut self) -> Option<FloatingSurfaceRequest>

One-shot request to hand app content to the shared floating-surface host. Shell and in-app hosts consume the same description, so PiP does not require a second rendering/widget API.

fn take_capture_studio_request(&mut self) -> Option<CaptureMode>

One-shot request for the session shell’s shared capture/PiP chooser.

fn take_floating_surface_source_updates(&mut self) -> Vec<(String, Rect)>

Rising-edge source-geometry updates for an adopted floating surface.

fn draw_floating_surfaces( &mut self, scene: &mut Scene, transform: Affine, text_renderer: &mut TextRenderer, theme: &Theme, presence: &PresenceCtx, )

Paint app-owned content whose presentation has moved into shell space.

fn draw_floating_surface( &mut self, id: &str, scene: &mut Scene, transform: Affine, text_renderer: &mut TextRenderer, theme: &Theme, presence: &PresenceCtx, ) -> bool

Paint exactly one app-owned presentation into its native window. Native secondary windows are independent buffers: painting the plural overlay pass into each would duplicate sibling surfaces and let content escape the window’s own clip.

fn set_floating_surface_bounds(&mut self, bounds: Rect)

Push the shell’s authoritative combined-output bounds into the owner.

fn floating_surface_presentations(&self) -> Vec<FloatingSurfacePresentation>

Desktop-space presentations that need a native secondary window.

fn active_floating_surface_ids(&self) -> Vec<String>

Stable IDs whose underlying activity still exists.

fn on_floating_surface_host_message( &mut self, message: &FloatingSurfaceHostMessage, )

Deliver an acknowledged shell lifecycle edge back to the owner.

impl FullscreenProvider for TileHost

fn fullscreen_intent(&self) -> Option<bool>

None means no opinion; otherwise this is a level-triggered intent.

fn fullscreen_params(&self) -> FullscreenRequest

Select the output and mirrored-vs-distinct presentation mode.

fn on_fullscreen_changed(&mut self, active: bool)

Report an actual OS fullscreen transition, including compositor exits.

impl LiveView for TileHost

fn state(&self) -> EmbedState

How it is coming along.

fn retries(&self) -> bool

Whether it is started again once RETRY passed while it does not show: a view whose record or code was still on its way shows once it is started again.

impl ResourceOperations for TileHost

fn start_operation( &mut self, op: &ResourceOperation<'_>, doc: &mut Edits<'_>, path: &ExId, ) -> Result<Option<ResourceOperationStart>, String>

Admit an exported effect or view operation. Document operations never enter it.

fn poll_resource_operation( &mut self, invocation: InvocationId, cancellation_requested: bool, doc: &AutoCommit, path: &ExId, ) -> Option<InvocationUpdate>

Poll one admitted operation without blocking the UI thread.

fn local_resource_operation_handlers(&self) -> &'static [&'static str]

Effect/view operation type ids this widget can actually dispatch.

fn resource_operation_handlers(&self) -> HashSet<String>

Every type this widget and its subtree dispatch.

impl SearchSource for TileHost

fn search_providers(&self) -> Vec<Box<dyn SearchProvider>>

One SearchProvider per findable kind.

fn search_provider_descriptors(&self) -> Vec<SearchProviderDescriptor>

Who each of search_providers is, as the action directory’s witness reads them. A source whose providers are costly to make (one that builds an index to answer from) overrides this to describe them without making them: the witness is read on every frame that publishes the action surface, a search only when someone searches.

fn search_index_state(&self) -> Option<IndexState>

What this source’s entries for the system’s persistent search index are of now; None for a source that publishes none. Read every frame that publishes, so it must not build anything: search_index_entries is asked only when this changes.

fn search_index_entries(&self) -> Vec<IndexEntry>

The entries the system’s persistent search index keeps for this source: short metadata keyed by the stable resource id a hit opens, found after the app closes too.

fn activate_search_result( &mut self, action_id: &str, doc: &mut Edits<'_>, path: &(dyn Any + 'static), )

Activate a hit: presentation (navigation), not a document action; mutate the model only if selecting changes shared state.

impl ViewState for TileHost

fn view_state(&self) -> Option<ViewContribution>

This root’s contribution, restored through Self::restore_view_state.

fn restore_view_state(&mut self, view: &ViewContribution)

impl Widget for TileHost

fn as_any(&self) -> Option<&(dyn Any + 'static)>

Lets a host that lays several tiles out in one tree find the window around a widget (the palette centres on the focused one).

fn scopes_keyboard_focus(&self) -> bool

The focused window’s tile is where Tab travels: the app’s controls, never the window’s bar or the desktop around it.

fn take_app_activation(&mut self) -> Option<u64>

An app does not bring itself forward; only its desktop does.

fn for_each_layout_child(&self, visitor: &mut dyn FnMut(&dyn Widget)) -> bool

The app also while History keeps it inert.

fn is_layout_dirty(&self) -> bool

The tile’s own node fills the window whatever it shows, so a notice or a stub has nothing to measure once laid out; app content and History report their own.

fn draw_overlay( &mut self, scene: &mut Scene, transform: Affine, text_renderer: &mut TextRenderer, theme: &Theme, presence: &PresenceCtx, )

The app’s top layer, over its own window: the tile is the viewport its dialogs centre on, its menus and tooltips stay inside, as a standalone app’s window is. Without this the top layer would see the whole screen the strip is drawn on and a dialog would centre there, spilling past a window narrower than the screen.

fn presented(&self) -> bool

Only an app can answer anything but true — a stub/notice is painted by this process and is on screen the moment the tile is.

fn take_structure_change(&mut self) -> StructureChange

The window’s content is laid out again in place under the tile’s retained node (StructureChange::Children): content that took a placeholder’s place, and an app that replaced widgets of its own, so the rest of the host’s tree is kept. Only a change of the tile itself rebuilds. Both flags are drained, so neither is left set behind the other.

fn remount_children(&mut self, remount: &mut Remount<'_>) -> bool

Lay the content that took a placeholder’s place out under the tile’s retained node; otherwise carry out the app’s own change.

fn provide<'a>(&'a self, request: &mut Request<'a, '_>)

Answer a request for a capability this widget takes part in (see capability). Declare capabilities with crate::provides!.

fn provide_mut<'a>(&'a mut self, request: &mut RequestMut<'a, '_>)

Exclusive counterpart to Widget::provide.

fn primary_vertical_scroll(&self) -> Option<PrimaryScrollRegion>

Explicit app-owned region; never search secondary children implicitly.

fn apply_primary_vertical_scroll( &mut self, action: PrimaryScrollAction, ) -> PrimaryScrollResult

fn mount_native_views(&mut self, host: &NativeViewHost<'_>)

Attach native child views through this owner’s retained lifecycle topology. Presentation containers with inactive or hidden live descendants override this traversal so lifecycle ownership stays independent of drawing and input visibility.

fn unmount_native_views(&mut self)

Tear native children down while their parent window still exists.

fn native_view_frame_start(&mut self)

Begin a native-view frame through this owner’s retained lifecycle topology.

fn on_external_event( &mut self, payload: &str, state: &mut Edits<'_>, root: &(dyn Any + 'static), )

Delivers an out-of-band string payload from crate::app::UserEvent::External (e.g. a worker thread streaming output into a status log). Default no-op; the App redraws and re-syncs after dispatch, so mutating state here is enough.

fn take_focus_reset(&mut self) -> bool

One-shot (reading MUST clear it) signal to move focus to this subtree’s first focusable widget after the next rebuild. Only consulted under crate::app::App::autofocus_on_structure_change; a wizard raises it on step transitions.

fn needs_idle_sync(&self) -> bool

Whether sync still needs to run on idle frames without input or collab events — e.g. waiting out a document-adoption grace window.

fn history_owner(&self) -> Option<HistoryOwner>

Opaque actual custody for framework History source registration.

fn has_separate_document_owner(&self) -> bool

Whether this widget introduces a document owner distinct from the runner’s outer State. This is a compatibility check, never identity or authority for history access or restore.

fn callback_binding(&self) -> Option<CallbackBinding>

Runtime binding inherited by descendants in a matching layout topology.

fn children(&self) -> Vec<&dyn Widget>

fn children_mut(&mut self) -> Vec<&mut dyn Widget>

fn sync(&mut self, s: &(dyn Any + 'static), p: &(dyn Any + 'static))

Pull model state into this widget before layout. The default syncs the children Widget::children_mut returns; a widget overrides it only to read state of its own, or to sync children it does not expose there.

fn settle(&mut self, edits: &mut Edits<'_>, path: &ExId)

Apply, after the sync pass, what the widget took up there and must write: a worker’s answer, a chooser’s file, an event a child queued. Writes go only through typed actions on edits; the host syncs again when the document changed. The default settles the returned children.

fn update(&mut self, s: &(dyn Any + 'static), p: &(dyn Any + 'static)) -> bool

Notice, between frames, state outside the document (a chrome revision, a momentum scroll still ticking) and report whether anything changed. The default updates every child Widget::children_mut returns without short-circuiting, so a container never freezes its descendants; an override checks state of its own and forwards.

fn build_layout( &mut self, taffy: &mut TaffyTree, theme: &Theme, node_map: &mut HashMap<NodeId, *mut dyn Widget>, ) -> NodeId

fn apply_layout(&mut self, taffy: &TaffyTree, node: NodeId, origin: Point)

Take the geometry layout gave this node. The default keeps none, for widgets that neither draw nor hit-test.

fn set_full_bleed(&mut self, full_bleed: bool)

The window holding this content fills its display (a maximized window): it has nothing beside it to round its corners against or to set it apart from, so content that frames or clips itself to the window’s shape draws edge to edge instead. A client surface drawn that way, last and unclipped, is one the display can scan out directly. Content that frames nothing ignores it.

fn draw( &mut self, scene: &mut Scene, transform: Affine, tr: &mut TextRenderer, theme: &Theme, presence: &PresenceCtx, )

Paint into scene. The default paints nothing.

fn needs_redraw(&self) -> bool

Default false (clean). A widget is clean until something it reads changes: a leaf that keeps state says so by tracking a dirty: bool (set in handle_event/sync, cleared in mark_drawn()), and one that paints from the people on the document reads the frame’s presence (crate::presence::frame::frame). Containers MUST forward: dirty iff any descendant is.

fn mark_drawn(&mut self)

Called after this widget’s scene lands in the composed frame, to clear a dirty flag. Default forwards to children.

fn handle_event(&mut self, event: &WindowEvent, ctx: &mut EventCtx<'_>)

Handle one input event with the runtime services for this retained node.

fn name(&self) -> &'static str

fn accessibility(&self) -> Option<AccessNode>

Role, name/description/value, and AccessState. Default None means presentational: the node is skipped and children reparent onto the parent. State must be derived, not stored so it can’t drift from draw; names must already be i18n!-resolved.

fn arrives_from(&self) -> Source

Where this content’s first frame comes from while it has not presented: this device (an app starting here), another device or a host. A frame from this device may hold the window’s first frame up to one frame budget; any other reserves the window’s place and says where it comes from after a while.

fn holds_frame_until(&self, now: Instant) -> Option<Instant>

Until when the frame that would show this subtree waits for data it reads from this device (crate::arriving): a local read that has not answered and is still inside its frame budget. The host keeps the frame on screen until then, or until the data lands, so the person never sees the space empty and then filled. Containers forward (the default does).

fn next_wake_deadline(&self) -> Option<Instant>

Earliest wall-clock deadline at which this subtree needs a sync or redraw with no input: the loop sleeps until then (not animation).

fn get_rect(&self) -> Rect

The rectangle this widget occupies. The default, for widgets that keep no geometry, is empty.

fn wants_pointer_capture(&self) -> bool

fn take_structure_dirty(&mut self) -> bool

True if this subtree’s structural composition changed since the last frame; reading clears it. The default drains every retained child and reports whether any was dirty.

fn needs_animation_frame(&self) -> bool

App polls this in Event::AboutToWait; without it a curve would freeze until an unrelated event woke it.

fn native_input_snapshot( &self, _state: &(dyn Any + 'static), _path: &(dyn Any + 'static), ) -> Option<Value>

Read-only state evidence for opt-in scheduled native input diagnostics. Called only around diagnostic inputs, never during ordinary input or paint. Keep this inexpensive and root-local; snapshots may be logged verbatim. This verifies widget state, not rendered pixels or display presentation.

fn view_only_scroll(&self, _event: &WindowEvent) -> bool

Opt in only when this wheel event changes scroll geometry and nothing else: no document edit, focus or selection, action availability, resource declaration, pending command or work that requires sync. The runner still lays out, paints and refreshes accessibility geometry; unknown handlers stay on the full path.

fn record_owners(&self) -> Vec<HistoryOwner>

Records this widget keeps open beside the document it shows, each synced on its own route: a framework app’s records in the person’s own workspace (crate::record::person). They take no part in this widget’s history or controls.

fn set_platform_conventions(&mut self, conventions: PlatformConventions)

Receive host-selected platform conventions. The default propagates to retained children, keeping target-OS branches out of app code.

fn set_interaction_environment(&mut self, environment: InteractionEnvironment)

Receive the host’s current input capabilities. The default propagates through retained containers, so app code does not need device branches.

fn set_window_bar_control(&mut self, in_bar: bool)

Tell this widget whether it stands in a window bar. A bar’s controls are drawn at the bar’s control height whatever the pointer; the target a finger needs reaches beyond the drawn shape, invisibly. The default propagates to children.

fn measure( &mut self, _known: Size<Option<f32>>, _available: Size<AvailableSpace>, _text_renderer: &mut TextRenderer, ) -> Size<f32>

fn layout_info(&self) -> Option<LayoutInfo>

Read-only resolved decisions for widgets with an explicit layout policy. None means the widget has no such policy; ordinary manual widgets remain valid. Values are available after build/settlement and carry real origins.

fn adjust_layout_style( &mut self, _taffy: &mut TaffyTree, _node: NodeId, _text: &mut TextRenderer, ) -> bool

Adjust this node’s style using its allocated size, before final geometry is applied. Return true only when the style changed (or an inherited decision child hooks read). An override may measure its owned children through ordinary references, entering their callback binding when present. Never reenter descendants through the raw node map while borrowing their parent, change topology, or build another layout tree. The shared host solver visits every registered widget, repeats layout at most eight times and skips a frame that does not settle.

fn observe_physical_input(&mut self, _input: PhysicalInput)

Observe this app’s ordinary foreground physical input before framework shortcuts consume it. Keep feedback ephemeral; this is not an input grant.

fn for_each_child(&self, visitor: &mut dyn FnMut(&dyn Widget))

Allocation-free read-only child traversal. Existing custom containers inherit a compatibility adapter over Self::children; toolkit containers override this to walk their retained storage directly.

fn for_each_child_in_clip(&self, visitor: &mut dyn FnMut(&dyn Widget))

The children of Self::for_each_child that may paint inside the layout_clip in effect: what a scroll view’s damage and copy plan need. Every child by default; a long column visits only those near the clip, so a frame costs what is shown, not what the column holds.

fn for_each_hosted_child(&self, _visitor: &mut dyn FnMut(&dyn Widget))

Children this widget keeps in the retained tree but does not route input to: a subtree it does not own and answers the person’s events for itself, like a host drawing another widget’s card over the windows. Inspection, named controls and the accessibility tree walk these after the children Self::children lists, so what is walked there keeps the paths, sibling indices and registry entries it had.

fn test_id(&self) -> Option<&str>

Stable id for the e2e test harness; None falls back to a path-based key. Must be unique across the live tree — the registry resolves on first match, so a duplicate shadows the second occurrence.

fn window_slot(&self, _id: String) -> Option<ToolbarAction>

This control as an action of the window’s bar, sent back as id (crate::window_toolbar::ToolbarAction): a button’s icon and name. None for anything that is not a button.

fn as_any_mut(&mut self) -> Option<&mut (dyn Any + 'static)>

fn stands_for(&self, address: *const ()) -> bool

Whether this widget is the one at address, or stands in the tree for it: a Decorator stands for every widget it wraps, so a scroller drawn inside one is found where the decorator is (crate::scroll_copy::offer).

fn focus_reveal_context(&self) -> Option<Rect>

Context that should remain visible with a focused descendant, such as a form control and its validation message. Opt-in scroll containers use this block when it fits; otherwise they prioritise the control.

fn reveal_descendant(&mut self, target: *const dyn Widget) -> bool

Reveal a newly keyboard-focused descendant inside any enclosing viewport. Containers override this to scroll; ordinary widgets simply recurse toward the target and report whether it was found.

fn test_rects(&self) -> Vec<(String, Rect)>

Named hit rects for widgets that paint several affordances into one rect instead of composing children. Same space as Widget::get_rect; zero-area entries are dropped.

fn child_clip_rect(&self) -> Option<Rect>

Absolute logical clip applied to ordinary children during painting and pointer routing. Inspectors and enclosing scroll regions must respect this boundary instead of treating clipped descendants as visible extent.

fn snap_points(&self, axis: ScrollAxis, out: &mut Vec<f32>)

Offsets along axis that this widget, as a scroll view’s content, offers it to settle on, measured from its own leading edge: a board’s lanes (crate::widget::Board). None leaves a scroller stopping wherever the hand left it.

fn take_action_palette_request(&mut self) -> Option<ActionAddress>

One-shot request to open the host’s action palette directly at a typed resource action. Parameter collection and permission checks remain host policy; widgets only name an address already present in resources().

fn take_search_request(&mut self) -> bool

One-shot request to open the host’s search palette, the same one the platform search shortcut opens. An app’s own search button latches it so search stays one shared host surface rather than an app overlay.

fn cursor_shape(&self, _point: Point) -> Option<CursorIcon>

point is logical coords, same space as Widget::get_rect; None defers to the default arrow. The host hit-tests the whole tree via node_map and picks the smallest-area claim, so containers need not override this.

fn claims_raw_touch(&self, _point: Point) -> bool

Opt out of touch-to-pointer emulation for contacts that begin at point (logical coords, same space as Widget::get_rect).

fn touch_claim(&self, _point: Point) -> TouchClaim

What a one-finger contact that begins at point (logical coords) means here, when a drag moves something rather than scrolling.

fn tooltip(&self) -> Option<&str>

Revealed after a dwell over the widget’s rect, via the toolkit’s one tooltip mechanism (crate::widget::tooltip::TooltipHost), hit-tested like cursor_shape so containers need not forward it. An icon-only control should also use this as its accessible name.

fn tooltip_side(&self) -> TooltipSide

Which side of the control its tooltip goes: below by default, beside it for a control in a vertical rail.

fn tooltip_target_at(&self, point: Point) -> Option<(Rect, String)>

fn is_focusable(&self) -> bool

fn is_default_keyboard_focus(&self) -> bool

Preferred control when its app is explicitly activated without a valid saved control. Hosts still enforce visibility, enabled state and scope.

fn keyboard_input_scope(&self) -> Option<u64>

Exact app instance whose non-text shortcuts this subtree owns when activation has no control target. Unbound desktop chrome may declare the active tab; component boundaries default to their captured owner.

fn set_focus(&mut self, _focused: bool)

fn set_invalid(&mut self, _invalid: bool)

The form’s validation verdict for this control, set by Field::with_error: an invalid control edges itself in danger ink and reports invalid to assistive technology. Controls without a field face ignore it.

fn focus_requested(&mut self, target: Option<NodeId>, tree: &TaffyTree)

An explicit runner focus request, after resolving the actual keyboard owner. Retained flags and layout restoration are not user gestures. Containers can observe this to reveal the owning viewport.

fn is_focused(&self) -> bool

fn context_menu_anchor(&self) -> Option<Rect>

The box a context menu opened from the keyboard stands against: the item that has the keyboard, so the menu opens under it rather than under the whole widget. A widget that holds items (a list) answers for the one with the keyboard; None leaves the menu to stand under the focused widget’s own box.

fn wants_tab_input(&self) -> bool

Whether a focused widget owns Tab instead of the host’s focus traversal. This is deliberately opt-in: ordinary form fields and controls retain platform-standard Tab/Shift+Tab navigation, while a code editor or terminal can receive the key for indentation or completion. A widget around the focus may claim it too: a sheet that walks its own controls with Tab.

fn ime_cursor_rect(&self) -> Option<Rect>

Caret rectangle for the platform input method, in window-logical coordinates. Returning Some enables IME for the focused widget and positions its candidate window; non-text controls keep the default None and therefore disable IME.

fn traps_focus(&self) -> bool

While any widget answers true, the host restricts Tab/directional focus to this subtree (wrapping at the ends) and restores the prior focus once it goes back to false. Default false.

fn take_focus_request(&mut self) -> Option<String>

One-shot (reading MUST clear it): the test id of the control this subtree asks to take the keyboard once the runner laid it out, such as the first field of a view a person’s press just opened, so what they type next lands there. The runner focuses it as a press focuses a control, blurring any other; a control it does not find (or that takes no focus) leaves focus where it is. Default forwards the first request found among the children.

fn accessibility_shared(&self) -> Option<SharedAccessNode>

Self::accessibility with its synthetic children shared, for a widget that keeps them between frames: each child it did not change is handed over as the very Arc of the last frame, which the semantic tree takes as unchanged without copying or comparing it.

fn accessibility_hidden(&self) -> bool

Whether Self::accessibility reports this subtree hidden, for a host that asks it of every node to prune focus traversal. Widgets whose node is costly to build (text values, per-block children, a translated name) answer without building it: the focus walk asks every widget in the window on every recomputation. Any override must agree with accessibility(); debug builds check it in the walk.

fn accessibility_root(&self) -> Option<AccessNode>

Self::accessibility’s own node with its children left empty: its role, identity (semantic_key) and state. Focus capture and focus order read only these, for every node on every frame, so a widget whose node carries a large subtree (a document exporting its every block) answers without building it. An override must equal accessibility() with children cleared.

fn synthetic_accessibility_rect(&self, _path: &[usize]) -> Option<Rect>

Geometry for an immediate-mode semantic child from AccessNode::children. The path is its child-index path beneath this widget’s accessibility node. Returning a rect lets AccessKit activation inject the same click as pointer input.

fn focus_synthetic_accessibility(&mut self, _path: &[usize]) -> bool

Move this widget’s own immediate-mode focus to a synthetic semantic child. Retained widgets continue to use the ordinary taffy focus path.

fn accessibility_child_parent(&self, _child_index: usize) -> Option<usize>

Reparent one retained children entry beneath a synthetic child returned by accessibility. The returned index addresses AccessNode::children for this frame. Collections use this to place a real interactive row delegate inside its virtual ListItem/TreeItem instead of exporting a duplicate.

fn accessibility_child_path(&self, child_index: usize) -> Option<Vec<usize>>

Reparent one retained children entry beneath a nested path of synthetic children returned by accessibility.

fn accessibility_represents_child(&self, _child_index: usize) -> bool

Whether one retained children entry is already represented in this widget’s own synthetic accessibility tree, so the bridge must not export it a second time. A host that publishes a child’s semantics itself (to add its own controls inside the same dialog) answers true for that child; assistive technology then sees one copy, not two.

fn lays_out_child(&self, _child_index: usize) -> bool

Whether this widget lays one retained children entry out itself (an Embedded part of a painted page) rather than through the window’s layout, which then gives it no node. The accessibility walk reaches such a child, and every widget inside it, through this widget’s node.

fn accessibility_child_description(&self, _child_index: usize) -> Option<String>

What describes one retained children entry to assistive technology, when this widget holds the words for it: a row’s secondary line is its trailing switch’s description. The bridge sets it as that child’s node’s description unless the child describes itself.

fn perform_action( &mut self, _action: &Action, _key_path: &[u64], _state: &mut Edits<'_>, _path: &(dyn Any + 'static), ) -> bool

Perform an accessibility Action on this widget, or on one of its synthetic accessibility nodes. May mutate the CRDT like handle_event.

fn perform_semantic_action( &mut self, target: &str, action: &Action, state: &mut Edits<'_>, path: &(dyn Any + 'static), ) -> bool

Handle an action addressed to a synthetic accessibility child created by this widget. target is the opaque stable value supplied through AccessNode::with_action_target.

fn is_enabled(&self) -> bool

A disabled (false) widget is excluded from focus traversal, must reject input in handle_event, and renders dimmed (see DISABLED_ALPHA).

fn ime_requires_deferred_ack(&self) -> bool

This field needs a host that consumes deferred receipts. Ordinary native Wayland windows must not advertise it until they have that delivery path.

fn ime_refuses_ordinary_commits(&self) -> bool

Ordinary input-method commits (a composing keyboard IME, the on-screen keyboard) cannot reach this field: its text arrives only through deferred receipts (a browser page field), so hosts keep standard text input closed outside a dictation session. A field that needs deferred receipts for dictation but turns an ordinary commit into its own acknowledged edit (Terminal’s native editor) does not refuse them.

fn start_deferred_text(&mut self) -> Option<Receipt>

Begin one bounded deferred session after explicit host consent, preserving the existing original-field fingerprint. This grants no microphone access.

fn commit_deferred_text(&mut self, text: &str) -> Option<Receipt>

A private asynchronous final. None leaves ordinary synchronous IME dispatch to the host. A receipt binds this original field and must be acknowledged before the host releases its private recovery transcript.

fn ime_content(&self) -> Option<InputContent>

The focused widget wants platform text input (Wayland text-input-v3, native IMEs elsewhere). None is intentionally the default: enabling an IME for buttons, canvas tools or games makes the compositor raise an on-screen keyboard over content that cannot accept the committed text.

fn ime_multiline(&self) -> bool

Whether the original focused editor accepts line feeds as text. This is field policy, never inferred from a multiline accessibility presentation. Wrappers inherit only one unambiguous child at their active IME caret.

fn ime_edit_fingerprint(&self, key: &[u8; 32]) -> Option<[u8; 32]>

Opaque local invalidation of deferred input, including selection edits that leave the caret rectangle unchanged. The host supplies an ephemeral secret key; no text or selection is retained in the resulting digest. The default shares the accessibility door and excludes protected or read-only controls. Text controls can override it to avoid cloning text.

fn arrival_progress(&self) -> Option<Progress>

How much of what this content’s first frame waits on has come, when that measures itself (its app downloaded before it starts).

fn arrival_shape(&self) -> SkeletonShape

The shape this content declares for the placeholder standing in for its first frame. Undeclared, the placeholder is the ground alone: nothing guesses what a window will show.

fn text_review(&self) -> Option<(usize, String)>

(caret_byte, text), byte offset on a char boundary. The host diffs this before/after an event so caret-only moves (arrows, Home/End) get announced, not just typing.

fn on_nav_gesture( &mut self, dir: NavDirection, state: &(dyn Any + 'static), path: &(dyn Any + 'static), ) -> bool

Global back/forward gesture (swipe/edge-pull), recognised by crate::gesture::NavGestureRecognizer and delivered to the whole tree; return true once consumed. Default forwards to children, so a widget that owns history becomes swipe-navigable for free.

fn nav_availability(&self) -> NavAvailability

Which directions Self::on_nav_gesture would consume now. A widget that owns history overrides this beside on_nav_gesture.

fn take_accessibility_request(&mut self) -> Option<AccessibilityRequest>

One-shot (reading MUST clear it) request to change the window’s accessibility preferences, raised by a control the person used. The host applies it before the next frame. Default forwards the first request found among the children.

fn dev_route(&self) -> Option<RouteSnapshot>

Route history when this widget, or one it contains, is a Router.

fn restore_dev_route(&mut self, route: &RouteSnapshot) -> bool

Put route back. Returns whether a router in this subtree accepted it.

fn appearance_intent(&self) -> Option<AppearanceIntent>

Theme/high-contrast/reduced-motion/scale, polled under crate::app::App::appearance_reconcile — how a settings pane re-themes the running app live without a back-channel. Level-triggered; the App recurses Self::children itself, so containers need not forward it. First Some wins.

fn minimum_window_width(&self) -> Option<f64>

The narrowest this window still works at, in logical pixels: the minimum of its compact layout (a NavShell answers with one column at a time). The host states it to the window system, so the desktop stops a resize there. None: no opinion. The host walks the tree itself (minimum_window_width), so containers need not forward it; the first Some wins.

fn preferred_window_size(&self) -> Option<(f64, f64)>

The whole size this window wants, in logical pixels, when the app is the window’s only content and knows how big it must be: the on-screen keyboard parked to a strip. The host states it as the window’s minimum and maximum, so the desktop shapes the surface to it. None: the window is the user’s and the app lays itself out in whatever it gets.

fn set_motion_reduced(&mut self, reduced: bool)

Apply the effective reduced-motion preference before the host asks this subtree whether it needs another animation frame. The default forwards recursively, making the preference a framework policy instead of an optional convention that every container has to remember to implement.

fn disclosing(&self) -> Option<Disclosing>

While this widget is a band on its way in or out (motion::Disclosure: an in-window banner arriving or leaving), or a content-sized container one moves in, how far what follows it is drawn from where it is laid out. A moving band stands out of the layout; its container places it (Self::place_disclosing) and draws the widgets after it lower by transform, so they move with the band’s edge instead of being laid out again every frame. None at rest (the default).

fn place_disclosing(&mut self, _slot: Rect)

Where a band on its way (Disclosing::Band) stands while it is out of the layout: its slot’s top and width (slot’s height is zero), set by its container after each layout.

fn is_band(&self) -> bool

A band that comes and goes (an in-window banner): when its view stops building it, its column draws it leaving (widget::Disclosing). Its column leaves it out of its identity across rebuilds.

fn note_placement(&mut self, _placement: Placement)

Where a band stands in its column, set by the column after each layout: what it leaves when dropped, so the column a rebuild makes can draw it leaving.

fn animation_detail(&self) -> Option<String>

Why this widget itself asks for animation frames, for diagnostics that name a desktop which keeps painting. None when it has nothing to add to its name and geometry.

fn serve_deadline(&mut self, _now: Instant) -> bool

A deadline this subtree asked for (Self::next_wake_deadline) is due at now: do the work it was for, and say whether anything changed. The default says it did.

fn modal_capture(&self) -> Option<Rect>

Some(rect) when this subtree holds an open modal, its panel box. While any widget reports Some, the host suppresses its own global focus shortcuts and swallows unhandled pointer presses so nothing behind the modal is clickable. Containers MUST forward (the default does, via first Some among children).

fn dismiss_presented_modal(&mut self) -> bool

Close every modal this subtree presents, as its own way out does (a host whose surface is a modal sheet calls it when the shell takes the sheet down). Whether any was presented; containers forward.

fn presents_modal(&self) -> bool

Whether this subtree presents a modal still drawn (arriving, open or leaving): the counterpart of Widget::dismiss_presented_modal.

fn has_pending_visual_work(&self) -> bool

Work already requested by this view whose completion will replace a placeholder. Unlike animations, this can be awaited by still captures.

fn has_transient_feedback(&self) -> bool

Temporary feedback currently presented, such as a save acknowledgement. Captures may intentionally include it; scene-invariance checks can wait for it to disappear separately from unfinished placeholder work.

fn collect_damage(&self, regions: &mut Vec<Rect>)

Logical-pixel bounds whose visual output differs from the last frame.

fn damage_covers_own_box(&self) -> bool

Whether, after this frame’s draw, this widget’s own Self::collect_damage covers every pixel a relayout changed by moving or resizing its layout box: a host that repaints where moved widgets were and are may then leave this widget’s box to it (its children’s boxes still count). A block editor that grew by a paragraph says where its blocks were and are; the default does not claim it.

fn mark_children_drawn(&mut self)

Rest this widget’s children after a frame drew them, for a widget that keeps its own dirty flag: it clears the flag itself, then calls this.

fn release_scene_cache(&mut self)

Release retained encoded-scene storage in this subtree without marking its visual/model state dirty. Outer caches call this after a successful reuse: while the outer display list is authoritative, keeping byte-for-byte descendant encodings only duplicates memory. A later outer rebuild causes descendants to record/cache normally.

fn composition_follows_allocation(&self) -> bool

Whether this widget composes its children from the size it was last allocated (it reads its own rect while building its layout: a compact layout under a width, a count of columns, an inset from a drawer). A window resize then needs a second composition against the new allocation, as well as the re-solve every resize gets. Widgets that compose independently of their allocation, or that report take_structure_dirty themselves when a new allocation changes what they show, keep the default: a resize re-solves the retained tree in place instead of recomposing all of it.

fn layout_needs_measure(&self) -> bool

Whether a layout_dirty frame needs taffy to re-solve sizes (compute_layout) rather than just reposition already-solved boxes. Scrollable is the motivating override: it translates its origin in apply_layout without changing any taffy size, so re-solving on every scroll frame is pure waste.

fn paint_bounds(&self) -> Rect

Everything this widget paints, children included; draw_child skips the draw when it misses the viewport. Override for widgets that paint past their own rect.