Struct Composer 

pub struct Composer { /* private fields */ }

Turns key transitions into characters, holding the state a layout needs.

Owns the dead-key latch, Caps Lock, Num Lock and the AltGr level, because all four are sequences rather than properties of a single event and none of them can be recovered from one keystroke in isolation.

Implementations

impl Composer

pub fn new(layout: &'static Layout) -> Self

A composer for layout, with Num Lock on as a keyboard reports it after a cold boot on most firmware.

pub const fn layout(&self) -> &'static Layout

The active layout.

pub fn set_layout(&mut self, layout: &'static Layout)

Switches layout, abandoning any half-finished composition.

pub const fn pending_dead(&self) -> Option<char>

The mark waiting for a base character, if any.

pub const fn caps_lock(&self) -> bool

Whether Caps Lock is latched.

pub fn feed( &mut self, code: KeyCode, state: ElementState, modifiers: Modifiers, ) -> Composed

Feeds one key transition and returns what it types.

modifiers is the state including this key, as the translator reports it.

pub fn output_for(&self, code: KeyCode, shift: bool) -> Output

What one position types right now, given whether Shift is held.

The composer’s own answer, including Caps Lock and the third level from its state — so an on-screen keyboard can letter a key with exactly what pressing it would produce. Caps Lock inverts shift for letters only, and asking here is how a keyboard gets that right without repeating the rule.

Trait Implementations

impl Clone for Composer

fn clone(&self) -> Composer

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Composer

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

Formats the value using the given formatter.