Struct NavShell 

pub struct NavShell { /* private fields */ }

The one window shell. See the module docs.

Implementations

impl NavShell

pub fn new() -> NavShell

An empty shell; give it columns with the builders.

pub fn toast(&mut self, text: impl Into<String>, kind: ToastKind)

Show a transient notice over the window’s bottom trailing corner: an operation’s result or failure. It replaces the one showing, expires on its own (held while the pointer rests on it and under the capture clock), and a click dismisses it.

pub fn dismiss_toast(&mut self)

Take down the notice showing, when its news no longer holds.

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

The notice showing, if any.

pub fn sidebar(self, sidebar: Box<dyn Widget>) -> NavShell

The sidebar of destinations (usually a crate::widget::NavList).

pub fn overview(self, overview: Box<dyn Widget>) -> NavShell

The overview list beside the content (a message list, a city list): content the person reads, not navigation.

pub fn overview_rail(self, rail: Box<dyn Widget>) -> NavShell

What the overview collapses into where the list no longer fits beside the content but a rail does: a crate::widget::NavList::rail of the same places, so the window narrows to rail and detail before it pushes.

pub fn content(self, content: Box<dyn Widget>) -> NavShell

The content.

pub fn inspector(self, inspector: Box<dyn Widget>) -> NavShell

The inspector at the trailing edge: properties of the selection.

pub fn overview_controls(self, controls: Box<dyn Widget>) -> NavShell

Controls that act on the overview list (its sort order, a scope), under the overview’s header at the shell’s inset.

pub fn sidebar_header( self, title: impl Into<String>, actions: Vec<Box<dyn Widget>>, ) -> NavShell

The sidebar column’s header: a sentence-case title and the app’s actions (buttons). The toggle is the shell’s; do not add one.

pub fn overview_header( self, title: impl Into<String>, actions: Vec<Box<dyn Widget>>, ) -> NavShell

The overview column’s header (the list’s title and its actions).

pub fn content_header( self, title: impl Into<String>, actions: Vec<Box<dyn Widget>>, ) -> NavShell

The content column’s header: the detail title and toolbar actions.

pub fn content_header_bound( self, title: &LocalState<String>, actions: Vec<Box<dyn Widget>>, ) -> NavShell

The content’s header with its title bound to title: a view names its content from resource state, and the header follows the state.

pub fn content_header_leading(self, leading: Box<dyn Widget>) -> NavShell

The fill of the content’s header between the shell’s leading buttons and the actions: a path bar or breadcrumb, or a mode or tab switcher with no title. It stands at its own width, and gets the room there is when it needs more.

pub fn inspector_header( self, title: impl Into<String>, actions: Vec<Box<dyn Widget>>, ) -> NavShell

The inspector column’s header.

pub fn overview_count(self, count: usize) -> NavShell

How many items the overview lists, after its title.

pub fn content_count(self, count: usize) -> NavShell

How many items the content shows, after its title.

pub fn with_filter(self, filter: SearchField) -> NavShell

The one filter field of the window, scoped to the sidebar’s list (or the overview when there is no sidebar, else the content), at the shell’s metrics. Ctrl+F (⌘F) focuses it. The shell carries its query to the column’s crate::widget::Filterable after every event and keeps the field: read it back with Self::filter.

pub fn mode(self, mode: NavMode) -> NavShell

What the sidebar becomes in a narrow window.

pub fn with_id(self, id: impl Into<String>) -> NavShell

Give the shell a stable id for tests and inspection; its headings group is keyed by it on the agent surface.

pub fn with_sidebar_hidden(self) -> NavShell

Start with the sidebar hidden (where it docks).

pub fn with_inspector_hidden(self) -> NavShell

Start with the inspector hidden (where it docks).

pub fn with_sidebar_state(self, state: &LocalState<bool>) -> NavShell

Keep whether the sidebar shows in state: the shell writes where it stands once laid out and every choice the person makes; setting the state shows or hides the sidebar (opens the drawer in a narrow window, from ViewCx::on_stage for a capture).

pub fn with_inspector_state(self, state: &LocalState<bool>) -> NavShell

Keep whether the inspector shows in state, as Self::with_sidebar_state.

pub fn with_pane_state(self, state: &LocalState<NavPane>) -> NavShell

Keep the front screen of a narrow window in state: a row of the overview can push the content by setting NavPane::Content, and the Back button writes the screen it returns to.

pub fn with_back<T>(self, stack: &LocalState<NavStack<T>>) -> NavShell

where T: Clone + PartialEq + 'static,

Bind the content’s Back to the app’s page stack: while stack can go back the shell shows its Back chip at the leading edge of the content’s header, and pressing it pops the stack (browse history, a drill-down from a dashboard into a queue). A narrow window’s push stack shares the chip: Back pops the app’s pages first.

pub fn on_back( self, can_go_back: impl Fn() -> bool + 'static, go_back: impl FnMut() + 'static, ) -> NavShell

The content’s Back for a page stack the app keeps itself: can_go_back is asked every frame, go_back runs on a press.

pub fn set_sidebar(&mut self, sidebar: Option<Box<dyn Widget>>)

pub fn set_overview(&mut self, overview: Option<Box<dyn Widget>>)

pub fn set_content(&mut self, content: Box<dyn Widget>)

pub fn set_inspector(&mut self, inspector: Option<Box<dyn Widget>>)

pub fn set_overview_rail(&mut self, rail: Option<Box<dyn Widget>>)

pub fn set_overview_controls(&mut self, controls: Option<Box<dyn Widget>>)

pub fn set_content_header_leading(&mut self, leading: Option<Box<dyn Widget>>)

pub fn set_sidebar_header( &mut self, title: impl Into<String>, actions: Vec<Box<dyn Widget>>, )

Change the sidebar’s header in place: its title and actions.

pub fn set_overview_header( &mut self, title: impl Into<String>, actions: Vec<Box<dyn Widget>>, )

Change the overview’s header in place.

pub fn set_content_header( &mut self, title: impl Into<String>, actions: Vec<Box<dyn Widget>>, )

Change the content’s header in place (the selected message’s subject and what can be done to it).

pub fn set_inspector_header( &mut self, title: impl Into<String>, actions: Vec<Box<dyn Widget>>, )

Change the inspector’s header in place.

pub fn set_sidebar_title(&mut self, title: impl Into<String>)

Change the sidebar’s title in place.

pub fn set_overview_title(&mut self, title: impl Into<String>)

Change the overview’s title in place.

pub fn set_content_title(&mut self, title: impl Into<String>)

Change the content’s title in place (the selected message’s subject).

pub fn set_inspector_title(&mut self, title: impl Into<String>)

Change the inspector’s title in place.

pub fn set_content_count(&mut self, count: Option<usize>)

Show or clear the count after the content’s title.

pub fn set_can_go_back(&mut self, can: bool)

Whether the content’s page stack can go back, for an app that keeps it itself (Self::on_back).

pub fn sidebar_mut<T>(&mut self) -> Option<&mut T>

where T: Widget + 'static,

The sidebar as the widget the app gave it (the one waiting to be shown, if a swap is pending), through its Widget::as_any_mut (which the widget answers with Some(self)).

pub fn overview_mut<T>(&mut self) -> Option<&mut T>

where T: Widget + 'static,

The overview as the widget the app gave it.

pub fn content_mut<T>(&mut self) -> Option<&mut T>

where T: Widget + 'static,

The content as the widget the app gave it.

pub fn filter(&self) -> Option<&SearchField>

The window’s filter field (Self::with_filter): its query and the count the filtered column reports.

pub fn filter_mut(&mut self) -> Option<&mut SearchField>

pub fn geometry(&self) -> &NavGeometry

The geometry of the last layout, in window coordinates.

pub fn has_sidebar(&self) -> bool

pub fn has_overview(&self) -> bool

pub fn is_sidebar_open(&self) -> bool

Whether the sidebar shows (docked and not hidden, or a drawer that is open, or the front push screen).

pub fn is_inspector_open(&self) -> bool

Whether the inspector shows.

pub fn front_pane(&self) -> NavPane

The front screen of the push stack (meaningful when it has more than one screen).

pub fn toggle_sidebar(&mut self)

Show or hide the sidebar, remembering the choice for this window size class. In NavMode::Push narrow, the sidebar is a screen: showing it goes back to it.

pub fn open_sidebar(&mut self)

pub fn close_sidebar(&mut self)

pub fn toggle_inspector(&mut self)

Show or hide the inspector, remembering the choice for this window size class (also while the app takes the inspector away and gives it back).

pub fn open_inspector(&mut self)

pub fn close_inspector(&mut self)

pub fn show(&mut self, pane: NavPane)

Bring pane to the front of a narrow window’s push stack. In a wide window every pane is already showing; this records which one a later collapse keeps in front.

pub fn back(&mut self) -> bool

Go back one screen: the app’s page stack first (Self::with_back), then a narrow window’s push stack. Returns whether it did.

pub fn snap(&mut self)

Snap every animation to its end (deterministic shots and tests).

Trait Implementations

impl ActionControls for NavShell

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 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 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 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 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 has_pending_control_invocation(&self) -> bool

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

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 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.

impl Default for NavShell

fn default() -> NavShell

Returns the “default value” for a type.

impl Widget for NavShell

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

The window’s group: keyed by the shell’s id, so what stands under a titled column keeps its identity on the agent surface while titles come and go. The column titles are its headings (the title parts).

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

A part whose overlay holds the pointer (a popover a header button owns, an open More menu) first; then the default.

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 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 sync(&mut self, state: &(dyn Any + 'static), path: &(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 update( &mut self, state: &(dyn Any + 'static), path: &(dyn Any + 'static), ) -> bool

Notice, between frames, state that lives 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 at build-time state; a widget overrides it to check state of its own and then forward.

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 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 is_layout_dirty(&self) -> bool

Default true; widgets with a fixed intrinsic size should override to false unless a size-affecting mutation landed. Containers MUST forward: layout-dirty iff any descendant is.

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

Paint into scene. The default paints nothing.

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

Top-layer pass, run once after the whole draw recursion, so anything emitted here composites above every sibling regardless of tree order — the toolkit’s overlay mechanism for content that escapes its layout box (an open Dropdown, a popover). Default recurses children_mut.

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

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

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

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

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

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

Downcast to the concrete widget, for hosts and tests that reach a known widget through dyn Widget. Default None (a widget may borrow and so not be 'static); a widget opts in with Some(self), and a Decorator answers itself.

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

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 get_rect(&self) -> Rect

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

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 next_wake_deadline(&self) -> Option<Instant>

Earliest wall-clock deadline at which this subtree needs a sync/redraw even if there is no input. Unlike needs_animation_frame, this keeps the event loop asleep until the requested instant and is appropriate for filesystem/status polling rather than animation.

fn needs_animation_frame(&self) -> bool

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

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 needs_redraw(&self) -> bool

Default true (dirty every frame). Opt into incremental redraw by tracking a dirty: bool, setting it in handle_event/sync, and clearing it in mark_drawn(). 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 collect_damage(&self, regions: &mut Vec<Rect>)

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

fn take_structure_dirty(&mut self) -> bool

True if this subtree’s structural composition (children inserted/removed) changed since the last frame; the App rebuilds the taffy tree when so. Reading clears it. The default drains every retained child (no short-circuit, so no child keeps a stale flag) and reports whether any was dirty; a leaf has no children and reports false. A container that changes its own child list sets its own flag and ORs it with this traversal.

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/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 synchronization/publication path.

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 callback_binding(&self) -> Option<CallbackBinding>

Runtime binding inherited by descendants in a matching layout topology.

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 history_owner(&self) -> Option<HistoryOwner>

Opaque actual custody for framework History source registration.

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 room (crate::record::person). They take no part in this widget’s history or controls.

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

Attach native child views through this owner’s retained lifecycle topology.

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 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 (a resource’s dispatcher); the host syncs again when the document changed. The default settles the children Widget::children_mut returns.

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 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>

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 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 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 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 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.

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 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 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 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_purpose(&self) -> Option<ImePurpose>

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 presented(&self) -> bool

Default true; the exception is a widget standing in for a process that has started but not drawn. Must latch: once true, never false again for the same content, or an un-presenting widget would make a window vanish mid-resize. What shows meanwhile is decided by Widget::opening.

fn opening(&self) -> bool

True once waiting long enough, while not yet presented, that showing nothing would read as broken. Delayed so a fast open never flashes an indicator.

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_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 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_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 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 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 take_committed_action(&mut self) -> Option<Vec<ChangeHash>>

The affordance-driven twin of the Ctrl+K palette: when a widget’s own control dispatches the same tilo_actions action its ActionSpec exports, it reports the document heads captured just before here, so the host can record one undo boundary the same way a palette dispatch does. Rising-edge: reading MUST clear it.

fn keeps_undo_step_open(&self) -> bool

Whether the undo step this widget’s last reported boundary opened stays open for the actions that continue it — the rest of a word typed a keystroke at a time. A hosted component then closes the step at the widget’s next boundary, or before an undo, a save or a merge, instead of after this event. Answered by the widget itself, never its children.

fn set_undo_status(&mut self, _status: &mut dyn FnMut() -> UndoStatus)

Host → widget: the live state of the undo history, published once per frame to every laid-out widget.

fn take_undo_request(&mut self) -> Option<UndoRequest>

Widget → host: an undo or redo the user asked for.

fn handle_local_undo_request(&mut self, request: UndoRequest) -> bool

Offer a host keyboard undo/redo shortcut to focused widget-local history before the application document consumes it.

fn apply_room_action( &mut self, _doc: &mut Edits<'_>, _type_id: &str, _payload: &[u8], ) -> bool

Apply an action another app in this room published, if this app owns the document — lets an app address a document it doesn’t hold by saying what should happen instead of writing bytes directly, keeping each document to one writer. An unrecognised type_id is silently declined, not an error.

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

Admit an exported effect or view operation: the one entry every handler implements. Document operations never enter it.

fn semantic_readers(&self) -> &'static [RegisteredSemanticReader]

Inert immutable-reader registrations owned by this actual widget. Registration alone supplies no qualified owner frame or disclosure.

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 wants_pointer_capture(&self) -> bool

fn take_structure_change(&mut self) -> StructureChange

Self::take_structure_dirty, saying whether the frame’s damage can still describe the rebuild (StructureChange::Described). Reading clears what take_structure_dirty clears; the two must agree on whether there is a change. The default is the flag, as a StructureChange::Rebuild: only a widget that knows every pixel its change touches lands in its own damage says less, and a container forwards a child’s StructureChange::Described only by overriding this.

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 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 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 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.

impl WindowHeader for NavShell

Controls in a column the shell is not showing (a hidden sidebar, a closed drawer, a screen pushed away) still belong to the window: custody, invocations and availability reach every part the shell owns.

fn set_history_control(&mut self, control: Option<HistoryControl>)

Show the window’s History control at the trailing edge of the row, or none (None: the app has no History, or the host’s own chrome presents it).