tuika 0.1.0

A small retained-tree terminal UI toolkit — flexbox layout, overlays, focus, and components over ratatui.
Documentation 
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//! Animation helpers: easing curves and a frame phase.
//!
//! `tuika` has no internal clock — the host owns time and passes a monotonically
//! increasing frame counter (yolop uses `App::busy_frame`) into animated
//! components. This module turns that counter into normalized progress and
//! shapes it with easing curves, the minimal analog of OpenTUI's Timeline API
//! without a scheduler or reconciler.

/// Normalized time in `0.0..=1.0`.
pub type Phase = f32;

/// Linear identity curve.
pub fn linear(t: Phase) -> Phase {
    t.clamp(0.0, 1.0)
}

/// Quadratic ease-in (slow start).
pub fn ease_in(t: Phase) -> Phase {
    let t = t.clamp(0.0, 1.0);
    t * t
}

/// Quadratic ease-out (slow end).
pub fn ease_out(t: Phase) -> Phase {
    let t = t.clamp(0.0, 1.0);
    1.0 - (1.0 - t) * (1.0 - t)
}

/// Cubic ease-in-out (slow start and end).
pub fn ease_in_out(t: Phase) -> Phase {
    let t = t.clamp(0.0, 1.0);
    if t < 0.5 {
        4.0 * t * t * t
    } else {
        let f = -2.0 * t + 2.0;
        1.0 - f * f * f / 2.0
    }
}

/// Triangle wave in `0.0..=1.0..=0.0` over one period, for ping-pong motion.
///
/// `frame` is the host's counter, `period` the number of frames for a full
/// there-and-back cycle.
pub fn ping_pong(frame: u64, period: u64) -> Phase {
    if period == 0 {
        return 0.0;
    }
    let pos = frame % period;
    let half = period as f32 / 2.0;
    let up = pos as f32 / half;
    if up <= 1.0 { up } else { 2.0 - up }
}

/// Sawtooth wave in `0.0..1.0`, wrapping every `period` frames, for looping
/// motion like an indeterminate marquee.
pub fn sawtooth(frame: u64, period: u64) -> Phase {
    if period == 0 {
        return 0.0;
    }
    (frame % period) as f32 / period as f32
}