Struct FramePacing 

pub struct FramePacing {
    pub now: FrameTime,
    pub interval: Duration,
    pub requested_interval: Option<Duration>,
}

The per-frame pacing context a shell hands to FrameGate::decide_paced: this tick’s frame clock, the active theme’s paced-loop cap, and whatever interval the previous paint’s paced request asked for.

All three are shell-owned: now is the platform frame clock (Choreographer / CADisplayLink timestamp — never a wall clock read inside frust-core), interval is 1 / MotionScheme::cosmetic_loop_rate resolved from the active theme each frame (so an app that retunes the token via ThemeBuilder re-paces live), and requested_interval is the previous paint’s latched PaintOutcome::paced_interval. effective_interval folds the last two into the one interval this tick actually paces at.

Fields

now: FrameTime

This tick’s shell frame-clock reading. Only differences of two FrameTimes from the same shell carry meaning (see FrameTime).

interval: Duration

The theme’s paced-loop cap: 1 / cosmetic_loop_rate from the active theme, and so the shortest interval any paced (CosmeticLoop) frame may be produced at. CosmeticLoopRate clamps its rate up to FLOOR_HZ (10Hz), so this is never longer than 100ms.

requested_interval: Option<Duration>

The tightest interval the previous paint’s paced requests named (frust_core::PaintOutcome::paced_interval, latched by the shell beside FrameInputs::last_needs_frame_paced_only), or None when that paint named none.

None and Some(Duration::ZERO) both mean “at the theme’s own rate” — a bare PaintCtx::request_frame_paced folds ZERO into the core-side MIN-lattice — so both resolve to interval. A longer value (a ~500ms caret blink against a 30Hz shimmer cap) paces that loop slower than the theme’s own cadence; see effective_interval.

Implementations

impl FramePacing

pub fn effective_interval(&self) -> Duration

The interval this tick actually paces at: the longer of the theme’s cap (interval) and the previous paint’s requested interval (requested_interval).

The two-sided contract behind that max (the core-side half lives on PaintCtx::request_frame_paced_at):

• The MIN fold already happened in core. Every paced request in a paint pass folds to the tightest interval there, so this sees one value: the fastest cadence anything onscreen asked for. A 30Hz shimmer beside a 2Hz caret arrives here as ZERO (the shimmer’s bare request) and paces at 30Hz — the caret is simply repainted more often than it needs, which is invisible and costs no frame the shimmer wasn’t already forcing. A slow request can never starve a fast one.
• The theme rate is a ceiling. cosmetic_loop_rate caps decorative motion for battery’s sake, so a request tighter than the cap is clamped up to it rather than honored. Motion that must land every vsync is not cosmetic — it belongs to TickClass::Transition, which is never paced at all.

Trait Implementations

impl Clone for FramePacing

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for FramePacing

impl Debug for FramePacing

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

Formats the value using the given formatter.