Struct PointerIdAllocator 

pub struct PointerIdAllocator { /* private fields */ }

Mints PointerIds and maps a backend’s reused contact ids onto them.

One instance per process, reached through PointerIdAllocator::global. The mapping is (device, os_id) -> PointerId, established at begin and torn down at end; get resolves the samples in between.

Implementations

impl PointerIdAllocator

pub fn global() -> &'static Self

The process-global allocator.

pub fn begin(&self, device: BackendDeviceKey, os_id: u64) -> PointerId

Mint a fresh id for a press and remember it for (device, os_id).

A second begin on a key that is already live replaces the mapping and returns a new id — a backend that drops an Up (a lost contact, a window that stopped receiving events mid-gesture) must not strand the next press on the old identity.

pub fn get(&self, device: BackendDeviceKey, os_id: u64) -> Option<PointerId>

The id minted for a live (device, os_id), if the contact is still down. None after end, which is what makes a reused OS id resolve to a new PointerId rather than the stale one.

pub fn end(&self, device: BackendDeviceKey, os_id: u64) -> Option<PointerId>

Forget the mapping for a lifted contact. Idempotent; returns the id that was live, if any.

pub fn live_count(&self) -> usize

Number of contacts currently mapped. Test/diagnostic helper.

Trait Implementations

impl Debug for PointerIdAllocator

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

Formats the value using the given formatter.