Struct KeyState 

pub struct KeyState { /* private fields */ }

Tracks which keys are currently held down.

Feed it every KeyEvent (or Event) you receive and query is_held each frame for held-key movement. A key is considered held from its first KeyEventKind::Press until a matching KeyEventKind::Release, or until apply_event sees an Event::FocusLost, whichever comes first.

Held keys are keyed by (KeyCode, KeyLocation), so a held Numpad8 and a held digit-row 8 are tracked separately: is_held takes the pair, and held yields it.

Release events are what actually clear a key, and not every backend emits them: plain terminals only ever report KeyEventKind::Press (see KeyEventKind). On those press-only backends a key never leaves the held set on its own – not even on focus loss, since there is no release to match – so call clear at a suitable boundary (e.g. once per turn) if you rely on held-key state there. Backends rich enough to emit releases (winit, or a terminal with the kitty keyboard protocol) are exactly the ones that also emit Event::FocusLost, so apply_event clears the held set on it: without that, alt-tabbing or clicking away while a key is down would leave it stuck held forever, since the release is delivered to whichever window/app gains focus instead.

Implementations

impl KeyState

pub const fn new() -> KeyState

Creates an empty key-state tracker.

pub fn apply(&mut self, event: KeyEvent)

Updates the held set from a key event.

Press and Repeat add the (code, location) pair; Release removes it.

pub fn apply_event(&mut self, event: &Event)

Updates the held set from an Event.

Key events update the held set as apply does; Event::FocusLost clears it entirely (see the type-level docs for why); every other event is ignored.

pub fn is_held(&self, code: KeyCode, location: KeyLocation) -> bool

Returns true if code at location is currently held.

pub fn held(&self) -> impl Iterator<Item = (KeyCode, KeyLocation)>

Iterates the currently held (code, location) pairs, in first-pressed order.

pub fn clear(&mut self)

Clears all held keys.

Trait Implementations

impl Clone for KeyState

fn clone(&self) -> KeyState

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for KeyState

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

Formats the value using the given formatter.

impl Default for KeyState

fn default() -> KeyState

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for KeyState

fn deserialize<__D>( __deserializer: __D, ) -> Result<KeyState, <__D as Deserializer<'de>>::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for KeyState

fn serialize<__S>( &self, __serializer: __S, ) -> Result<<__S as Serializer>::Ok, <__S as Serializer>::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.