Trait Platform 

pub trait Platform: Toolkit {
    const TARGET: &'static str;
    const TOOLKIT: &'static str;

    // Required methods
    fn run(
        self,
        options: WindowOptions,
        ready: Box<dyn FnOnce(Self, Self::Handle, Size)>,
    );
    fn post(f: Box<dyn FnOnce() + Send>);

    // Provided methods
    fn post_delayed(ms: u32, f: Box<dyn FnOnce() + Send>) { ... }
    fn request_frame(_cb: Box<dyn FnOnce(f64) + 'static>) { ... }
    fn locale_hints(&self) -> Vec<String> { ... }
}

A platform backend: owns the native main loop and exactly one window in v1 (§8.1).

run sets up the native app + window, installs the reactive scheduler + main poster, then hands (self, root_container, content_size) to ready — which mounts the tree and takes ownership of the backend — and finally runs the native main loop.

Required Associated Constants

const TARGET: &'static str

e.g. "macos-appkit" — the process-constant target id.

const TOOLKIT: &'static str

The toolkit half of the target, e.g. "appkit".

Required Methods

fn run( self, options: WindowOptions, ready: Box<dyn FnOnce(Self, Self::Handle, Size)>, )

fn post(f: Box<dyn FnOnce() + Send>)

Post a closure onto the native main loop. Callable from ANY thread; this is the single door the reactive scheduler and Setter deliveries ride (§3.3).

Provided Methods

fn post_delayed(ms: u32, f: Box<dyn FnOnce() + Send>)

Post f onto the native main loop after (at least) ms milliseconds — the timer door behind day::sleep (docs/async.md). The default spawns a helper thread that sleeps and rides Platform::post home, which is correct on every threaded platform with zero backend code; a single-threaded host (web) overrides it with the platform’s own timer.

fn request_frame(_cb: Box<dyn FnOnce(f64) + 'static>)

Request a single main-thread callback aligned to the next display refresh (vsync), carrying the frame timestamp in seconds. The day-core animation driver re-arms it each tick while animations / game frame-clocks are live and stops requesting when none remain (no idle wakeups → battery). Main-thread only. A backend without a display link may approximate with a ~16 ms timer. Defaulted no-op: the canvas/self-driven animation path is inert until a backend provides it (native-widget animation via AnimSpec is unaffected). (§8.4)

fn locale_hints(&self) -> Vec<String>

Ordered OS locale preference list (BCP-47), for fluent-langneg (§12.2).

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors