Struct FocusGraph 

pub struct FocusGraph { /* private fields */ }

Directed graph for focus navigation.

Nodes are focusable widgets; edges encode directional navigation. The graph is sparse (most nodes have ≤6 outgoing edges).

Implementations

impl FocusGraph

pub fn new() -> Self

Create an empty graph.

pub fn insert(&mut self, node: FocusNode) -> FocusId

Insert a node. Returns the node’s ID.

If a node with the same ID exists, it is replaced.

pub fn remove(&mut self, id: FocusId) -> Option<FocusNode>

Remove a node and all edges incident on it.

Returns the removed node, or None if not present.

pub fn connect(&mut self, from: FocusId, dir: NavDirection, to: FocusId)

Connect two nodes: navigating dir from from leads to to.

Both nodes must already exist. Silently no-ops if either is missing.

pub fn disconnect(&mut self, from: FocusId, dir: NavDirection)

Disconnect an edge.

pub fn navigate(&self, from: FocusId, dir: NavDirection) -> Option<FocusId>

Navigate from a node in a direction.

Returns the target node ID, or None if no edge exists.

pub fn get(&self, id: FocusId) -> Option<&FocusNode>

Look up a node by ID.

pub fn node_count(&self) -> usize

Number of nodes.

pub fn edge_count(&self) -> usize

Number of edges.

pub fn is_empty(&self) -> bool

Whether the graph is empty (no nodes).

pub fn node_ids(&self) -> impl Iterator<Item = FocusId> + '_

All node IDs.

pub fn tab_order(&self) -> Vec<FocusId>

Nodes in tab order (ascending tab_index, ties broken by ID). Skips nodes with tab_index < 0 or !is_focusable.

pub fn group_tab_order(&self, group: u32) -> Vec<FocusId>

Nodes in a specific group, in tab order.

pub fn find_cycle(&self, start: FocusId) -> Option<Vec<FocusId>>

Detect a cycle reachable from start following Next edges.

Returns Some(cycle) where cycle is the sequence of node IDs forming the cycle (starting and ending at the same node), or None.

Uses tortoise-and-hare for O(V) time, O(1) extra space.

pub fn find_cycle_in_direction( &self, start: FocusId, dir: NavDirection, ) -> Option<Vec<FocusId>>

Detect cycles reachable from start following any single direction.

More general than find_cycle (which only follows Next).

pub fn build_tab_chain(&mut self, wrap: bool)

Build bidirectional Next/Prev chain from the current tab order.

Overwrites existing Next/Prev edges. If wrap is true, the last node links back to the first (and vice versa).

pub fn clear(&mut self)

Clear all nodes and edges.

Trait Implementations

impl Debug for FocusGraph

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for FocusGraph

fn default() -> FocusGraph

Returns the “default value” for a type.