Struct SemanticsCtx 

pub struct SemanticsCtx { /* private fields */ }

Collects accesskit::Nodes during a semantics pass, tracking the current absolute origin/size (mirroring paint’s origin threading) and the parent/child structure.

Node ids are stable across passes: each node’s id is composed from the owning ChildPod’s persistent base id (assigned on first visit from a monotonic, never-reused RenderRoot allocator and threaded in through SemanticsCtx::new) and a per-pod sub-node slot (see [compose_node_id]) — so the same widget keeps the same id every frame, including across a keyed reorder that relocates its pod. accesskit TreeUpdates require stable ids for assistive-technology focus continuity. Bounds are derived from the current absolute origin/size when a node is pushed, so a widget never computes its own absolute rect.

Implementations

impl SemanticsCtx

pub fn origin(&self) -> Point

The absolute origin of the widget currently being visited.

pub fn size(&self) -> Size

The size of the widget currently being visited.

pub fn push_node(&mut self, role: Role, build: impl FnOnce(&mut Node)) -> NodeId

Contribute a leaf semantics node for the current widget.

Allocates a node id, creates an accesskit::Node of role with its bounds set from the current absolute origin/size, lets build set the label/state, records it as a child of the enclosing node, and appends it to the flat map. Returns the allocated id (e.g. so a widget can set_focused it).

pub fn push_container( &mut self, role: Role, build: impl FnOnce(&mut Node), visit: impl FnOnce(&mut SemanticsCtx), ) -> NodeId

Contribute a container semantics node whose accesskit children are the nodes contributed during visit.

Like push_node but opens a fresh child frame, runs visit (which recurses into the container’s ChildPods via semantics_child), then sets the collected ids as this node’s Node::set_children. The container node is appended to the flat map after its children (post-order), but is still registered as a child of its own parent frame.

pub fn set_focused(&mut self, id: NodeId)

Record that the node id holds input focus (accesskit tracks focus at the tree level, not per-node). The last widget to call this in a pass wins.