Struct BlockEditor 

pub struct BlockEditor { /* private fields */ }

Implementations

impl BlockEditor

pub fn new() -> BlockEditor

Starts with one empty paragraph — there must be a block to focus.

pub fn with_empty_hint(self, hint: &str) -> BlockEditor

pub fn with_wrap_lines(self, wrap: bool) -> BlockEditor

pub fn with_compact_paragraph_spacing(self, compact: bool) -> BlockEditor

pub fn set_empty_hint(&mut self, hint: &str)

pub fn set_tooltip_viewport(&mut self, viewport: Option<Rect>)

Restrict tooltip targets to the host’s visible document viewport. Hosts must refresh this after scrolling or resizing, using the same window-coordinate clip as painting (including the handle gutter).

pub fn empty_hint(&self) -> &str

pub fn take_edit_ops(&mut self) -> Vec<BlockEditOp>

The user’s edits since the owner last took them, as semantic block operations for the owner to submit as actions. The editor never writes the document itself.

pub fn take_pending_semantic_ops(&mut self) -> Vec<BlockEditOp>

Drain UUID-addressed edits requested through synthetic AT controls.

pub fn from_markdown(md: &str) -> BlockEditor

Minimal markdown parser; empty input still produces one empty paragraph.

pub fn to_markdown(&self) -> String

Inverse of from_markdown; round-trip is byte-stable.

pub fn is_dirty(&mut self) -> bool

Drains per-block + edit-pending dirty; structure_dirty is only peeked here, and stays set until take_structure_dirty.

pub fn is_focused(&self) -> bool

pub fn suppress_caret_paint(&mut self, suppressed: bool)

Hide insertion carets while a modal owns input; retain editing state.

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

pub fn blocks(&self) -> &[Block]

pub fn content_bottom(&self) -> f64

Lowest painted edge, including formula previews that intentionally sit below their editable source line inside the same layout child.

pub fn blocks_mut(&mut self) -> &mut Vec<Block>

For tests + notes-app persistence to seed blocks directly; production code should prefer the public mutators.

pub fn take_edit_scope(&mut self) -> EditScope

Which blocks the person may have changed since the last call: a host that owns the document compares only those with what it presented. Plain typing in a paragraph names that paragraph and its neighbours; anything else (a structural edit, a pointer, an action, direct access to the blocks) may have changed any block.

pub fn note_edit_anywhere(&mut self)

Treat any block as possibly changed: for a host that changes blocks through Self::blocks_mut or other direct access.

pub fn set_blocks(&mut self, blocks: Vec<Block>)

For the notes app’s markdown parser, which produces a richer representation (inline marks) than this widget’s from_markdown.

pub fn with_read_only(self, read_only: bool) -> BlockEditor

Show the blocks without taking input or focus: a read-only view of rich text (a sent message, a comment reply).

pub fn handle_gutter(&self, theme: &Theme) -> f64

The handle gutter of a block document: the lane its drag handles hang in, outside the text column, as wide as a handle and the gap to the text. Zero when the editor shows no handles.

A page that holds the editor keeps its one content gutter outside this lane: it places the editor’s rect on its gutter and lines its title and metadata up with the text (Self::text_inset in from the rect), so a hovered handle stands a full gutter clear of the sidebar or window edge beside the page.

pub fn text_inset(&self, theme: &Theme) -> f64

How far a paragraph’s text starts inside the editor’s rect: the handle gutter (when shown) or the lines’ own text inset, whichever is wider. Every block kind starts at this edge, so a host lines a title, a caption or a composer’s controls up with it instead of measuring a laid-out caret.

pub fn with_block_handles(self, shown: bool) -> BlockEditor

Show or hide the drag handle beside each block. A composer or a read-only row has none: its blocks are not rearranged by dragging.

pub fn set_mention_paint( &mut self, paint: Option<Rc<dyn Fn(&str) -> MentionColors>>, )

Paint mentions in the colours paint gives each participant.

pub fn insert_text(&mut self, text: &str) -> bool

Put text at the caret of the focused block, replacing a selection within it: an emoji picked from a menu, a pasted snippet. Returns whether there was a block to put it in.

pub fn insert_mention(&mut self, id: &str, label: &str) -> bool

Put a mention of the participant id, shown as label (@Ada), at the caret of the focused block, followed by a space. The label is one marked run, so it reads back as a reference, not as text that happens to start with @.

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

The focused block’s text before the caret: what an autocomplete reads its query from (@ad while a mention is typed).

pub fn select_before_caret(&mut self, bytes: usize)

Select the bytes before the caret in the focused block, so the next insertion replaces them (the typed @ad a picked mention replaces).

pub fn set_read_only(&mut self, read_only: bool)

Stop or resume taking input and focus.

pub fn with_text_align(self, align: TextAlign) -> BlockEditor

Align every line within the editor’s width: a text box whose alignment belongs to the box rather than to each paragraph.

pub fn set_text_align(&mut self, align: TextAlign)

Change how every line is aligned.

pub fn text_align(&self) -> TextAlign

How every line is aligned.

pub fn with_body_size(self, px: f32) -> BlockEditor

Size body text at px logical pixels; every other kind keeps its size relative to body text.

pub fn set_body_size(&mut self, px: f32)

Change the body text size (see Self::with_body_size).

pub fn body_size(&self) -> f32

The body text size, in logical pixels.

pub fn is_read_only(&self) -> bool

Whether the editor shows its blocks without taking input.

pub fn select_all(&mut self)

Select every block’s text, as Ctrl+A does.

pub fn has_open_popup(&self) -> bool

Whether a menu or popover of the editor is open and takes Escape and Enter itself (the slash menu, a link picker, find).

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

The id local edits are attributed to, if any.

pub fn set_local_author(&mut self, author: Option<String>)

pub fn bind_existing_blocks( &mut self, state: &AutoCommit, list: ExId, ) -> Result<(), ThawError>

Bind a canonical existing list without initializing its durable contents.

Errors

Rejects malformed identities, kinds or Text objects before installing local state.

pub fn bind_existing_block_objects( &mut self, state: &AutoCommit, objects: &[ExId], ) -> Result<(), ThawError>

Adopt an action owner’s ordered projection of existing block objects.

The owner resolves hierarchy and ordering, then reprojects after document changes. Storage order need not match display order, and moving an object never requires replacing its collaborative Text. Like list binding, this method is read-only and local edits are emitted as semantic operations.

Errors

Rejects malformed or duplicate identities and non-Text bodies before changing the editor. The owner supplies its visible canonical block Maps.

pub fn focused_index(&self) -> Option<usize>

pub fn is_composing(&self) -> bool

Whether the active source line or projected table cell owns an IME preedit.

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

pub fn open_find(&mut self)

Opens the shared in-document find overlay without touching document state. Hosts may call this for a window-level Find command even when a sibling field currently owns focus.

pub fn set_find_replace_enabled(&mut self, enabled: bool)

Enable replacement only when a canonical host consumes its requests.

pub fn take_find_replace_request(&mut self) -> bool

pub fn find_replace_request(&self) -> Option<(FindReplaceTarget, String)>

The replacement payload keeps byte endpoints and original block identity.

pub fn take_find_replace_all_request(&mut self) -> bool

pub fn can_replace_all(&self) -> bool

pub fn find_replace_all_request(&self) -> Option<FindReplaceBatch>

Clone the snapshot only when a canonical host consumes the action.

pub fn finish_find_replace_all(&mut self)

pub fn finish_find_replace( &mut self, target: &FindReplaceTarget, replacement_len: usize, )

Move beyond inserted text, refresh matches, and retain overlay focus.

pub fn focus_block(&mut self, idx: usize, cursor_at: CursorPlacement)

pub fn split_at_cursor(&mut self, idx: usize, split_at: usize)

Splitting at byte 0 of an empty block still produces two blocks — how the user gets a blank line by hitting Enter twice.

pub fn merge_with_previous(&mut self, idx: usize)

No-op at idx == 0. The surviving block keeps the previous block’s kind — backspacing a paragraph into a heading folds the text into the heading, not the reverse.

pub fn delete_empty(&mut self, idx: usize)

Never deletes the last block — the editor always retains at least one paragraph to receive focus.

pub fn try_promote_to_heading(&mut self, idx: usize) -> bool

The caller must restrict when this runs — it must only fire on the keystroke right after an empty paragraph, or typing # mid-paragraph would promote wrongly; see handle_event.

pub fn try_promote_to_quote(&mut self, idx: usize) -> bool

Converts a freshly typed > paragraph prefix into a semantic quote.

pub fn toggle_mark(&mut self, mark: Mark) -> bool

Toggle mark as a toolbar button does: over the focused block’s selection, or, with nothing selected, for the text typed next. false when no block is focused.

pub fn active_marks(&self) -> Vec<Mark>

The marks a toolbar shows as on: those covering the whole selection in the focused block, or the caret, with the ones set for the text typed next.

pub fn insert_link(&mut self, target: &str) -> bool

Link the focused block’s selection to target, or, with nothing selected, insert target at the caret as its own linked text. false when no block is focused or target is blank.

pub fn focused_kind(&self) -> Option<&BlockKind>

The focused block’s kind.

pub fn try_convert_to(&mut self, idx: usize, new_kind: BlockKind) -> bool

Preserve authored formatting, caret, binding and outline context. Converting to a divider intentionally removes the contents.

pub fn try_indent(&mut self, idx: usize, delta: i8) -> bool

Shift an item and all descendants together, preserving their relative depths. Clamp the entire operation rather than flattening deep children.

pub fn selected_block_range(&self) -> Option<Range<usize>>

Selected roots and their descendants, including entire code fences. A selection ending at column zero does not include that block.

pub fn block_group_range(&self, index: usize) -> Option<Range<usize>>

One block’s complete authored fence and outline descendants.

pub fn selected_block_move(&self, up: bool) -> Option<(Range<usize>, usize)>

Plan a selected sibling batch’s move past its adjacent sibling subtree. Returns the source rows and the insertion boundary in the current order. A move never implicitly changes a root’s parent or splits a code fence.

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

Host calls this AFTER the main draw pass — popovers must paint last so they land above every other widget.

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

Where the drag handle the pointer’s block shows was painted, if any: it follows the pointer, not the text, so a host that copies a scroll of the text repaints it where it is and where it was.

pub fn pointer_chrome(&self) -> Vec<Rect>

Everything the last draw may have painted for where the pointer is rather than where the text is: the hovered block’s drag handle, the copy chrome of each code run (lit under the pointer), each table’s add-row and add-column controls (shown under it) and each image’s button (shown under it). The text moves under a resting pointer, so a host that copies a scroll of the text repaints these where they are and where they were.

pub fn set_link_pages(&mut self, pages: Vec<PageEntry>)

pub fn set_image_store(&mut self, store: Option<ImageStore>)

Supply an asynchronous, host-policy-owned image loader. The editor never performs filesystem or network access itself.

pub fn link_popover(&self) -> &FilterMenu<PageEntry>

pub fn link_at_point(&self, point: Point) -> Option<LinkTarget>

Resolve a link against the exact geometry produced by the live draw. A stale layout intentionally refuses rather than approximating with a different theme or font.

pub fn set_transclusion_previews( &mut self, previews: HashMap<Uuid, TransclusionPreview>, )

pub fn take_transclusion_open(&mut self) -> Option<Uuid>

pub fn take_external_link_open(&mut self) -> Option<String>

pub fn take_pasted_images(&mut self) -> Vec<ClipboardImage>

Images for legacy hosts which insert after the caret. Canonical hosts use Self::take_image_paste_requests to replace the captured selection.

pub fn take_image_paste_requests(&mut self) -> Vec<ImagePasteRequest>

Drain image intents without changing text. The host validates the image and applies asset storage and the captured replacement in one action.

pub fn slash_menu_visible(&self) -> bool

So the host can avoid stealing focus from the popover.

pub fn try_toggle_check(&mut self, idx: usize) -> Option<bool>

No-op for non-Checklist kinds.

impl BlockEditor

pub fn document_selection(&self) -> Option<DocumentSelection>

pub fn select_document_range( &mut self, anchor: DocumentPosition, cursor: DocumentPosition, )

Set and paint a document range using UTF-8 byte offsets. Positions are clamped to existing block/character boundaries.

pub fn retain_block_selection(&mut self, ids: Vec<String>, reverse: bool)

Retain the exact batch after a structural command, including empty rows. Missing or interleaved IDs refuse restoration instead of selecting peers.

pub fn clear_document_selection(&mut self)

Clear selection and its keyboard/drag anchors without changing text.

pub fn selected_text(&self) -> Option<String>

Plain-text serialization uses a newline for every crossed block boundary, matching browser/contenteditable clipboard behavior.

pub fn replace_document_selection(&mut self, replacement: &str) -> bool

Replace a cross-block selection with normalized plain text. All local mutations happen in this call, so the host commits one Automerge undo boundary for the originating key/IME event.

impl BlockEditor

pub fn present_blocks(&mut self, blocks: &[BlockContent]) -> bool

Show blocks as the owning model has them now: after a collaborator’s edit, an undo, or the host’s read-back of an edit it applied. A block whose id stays keeps its widget, with the caret carried past text inserted or removed before it; focus and a selection follow their block’s id. Returns whether anything changed.

Edits the person makes still arrive as the editor’s own blocks (Self::blocks); a host that owns the document compares them with what it presented, applies the difference to its model, and presents the result.

pub fn present_changed( &mut self, changed: &[(usize, &BlockContent)], ) -> Option<bool>

Show new content for some blocks, the rest as they are: changed pairs a block’s index with what it shows now, and each index must still hold the block with that content’s id. For an owning model that knows which paragraphs an edit touched, so a keystroke’s read-back costs the blocks it changed, not the document. Returns None, presenting nothing, when a pair names another block (the order changed: present everything with Self::present_blocks), otherwise whether anything changed.

pub fn rename_block(&mut self, from: &str, to: &str) -> bool

Give block from the id to: the owning model named a block the editor created (the paragraph an Enter split off) when it applied the edit. Returns whether a block was renamed.

pub fn set_presence_key(&mut self, key: Rc<dyn Fn(&str) -> PresenceKey>)

Address blocks in presence by the owning model’s keys (a resource selection, say) rather than the editor’s own, so a collaborator’s caret lands in the same paragraph of the same resource.

Trait Implementations

impl Default for BlockEditor

fn default() -> BlockEditor

Returns the “default value” for a type.

impl PublishesPresence for BlockEditor

fn presence_payload(&self) -> Option<(PresenceKey, PresencePayload)>

Outbound presence (typically caret/selection) broadcast while this widget holds focus; the host polls the focused widget after each event and diffs it out to peers.

fn presence_key(&self) -> Option<PresenceKey>

Stable identity for presence and permission lookup.

impl Widget for BlockEditor

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

Block lines are not children, so their fields’ timers (a settling squiggle, a suggestion for the word under the caret) are collected here alongside the children’s.

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

Assistive technology sets the whole text (one paragraph, line breaks kept) or selects by grapheme offsets into the text, paragraphs joined by a line break.

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

Block contents are not surfaced as a value — a screen reader walks the per-block subtree instead.

fn damage_covers_own_box(&self) -> bool

Its damage after a draw says where each block was and is, or repaints where the editor painted then and paints now.

fn is_layout_dirty(&self) -> bool

The editor is a column of one taffy node per line; its own margins and formula minimums are styles set at build time (a structural change), so its size can only move when a line’s does. Forwarded per line rather than through children(), which the editor does not expose, so an idle document re-measures nothing.

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

Paint into scene. The default paints nothing.

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

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

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

fn set_focus(&mut self, focused: bool)

fn is_focused(&self) -> bool

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

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

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 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 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 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 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 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 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 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 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 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 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_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 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 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 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 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 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 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 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 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.

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.