Struct A11yTree 

pub struct A11yTree { /* private fields */ }

Builds and diffs accesskit TreeUpdates from an A11yNode tree.

The struct stores the flat map of nodes (by NodeId) after a build, so subsequent calls to A11yTree::diff can compute minimal deltas.

The content-hash map (hashes) stores the OxiUI-side hash of each node at the time of the last build_and_store call. A11yTree::diff uses these hashes instead of format!("{:?}", node) string comparison, which avoids the overhead of serializing accesskit::Node (which doesn’t impl PartialEq).

Implementations

impl A11yTree

pub fn build(root: &A11yNode) -> TreeUpdate

Walk root and its descendants depth-first, producing a TreeUpdate that describes the full tree.

Also stores the snapshot internally so future diff calls can compute minimal deltas.

pub fn build_and_store(&mut self, root: &A11yNode) -> TreeUpdate

Build the full tree and store the snapshot for later diffing.

Returns a TreeUpdate identical to A11yTree::build.

In addition to the AccessKit snapshot, this method collects the OxiUI-side content hash of every node and stores it in self.hashes. A11yTree::diff uses these hashes for efficient change detection.

pub fn set_focus(&mut self, id: Option<NodeId>)

Set the currently-focused node.

Pass None to clear the focus (the adapter will typically move focus back to the root).

pub fn focus(&self) -> Option<NodeId>

Return the currently-focused node, if any.

pub fn focus_update(&self) -> TreeUpdate

Produce a minimal TreeUpdate that only updates the focus field.

Useful when only focus has changed and no node properties have changed.

pub fn announce(&mut self, text: &str, urgency: LiveSetting) -> NodeId

Insert a transient live-region announcement node.

Creates a synthetic accesskit::Role::Status node carrying text as its value, with the live-region politeness derived from urgency. The node is appended to the internal snapshot; the caller is responsible for removing it on the next tick (by calling build_and_store with a tree that doesn’t include this id).

Returns the newly-allocated NodeId so the caller can track it.

pub fn diff(old: &A11yTree, new_tree: &A11yTree) -> TreeUpdate

Compute a minimal TreeUpdate delta from old to new_tree.

Only nodes whose content has changed (or that are brand-new) are included in the returned nodes list. Nodes that were removed are handled implicitly by AccessKit: when the parent’s children list no longer references a node, the platform adapter orphans it.

Change detection uses the OxiUI-side content hashes stored in self.hashes rather than format!("{:?}", accesskit::Node) string comparison. This is both faster and correct: accesskit::Node does not implement PartialEq, so the Debug-string approach was a pragmatic workaround. The hash approach is O(1) per node after the initial build.

The returned update’s focus is taken from new_tree.focus.

Trait Implementations

impl Default for A11yTree

fn default() -> A11yTree

Returns the “default value” for a type.