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Tempa

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A no_std library for working with time in animation and real-time systems.

It provides a small set of temporal primitives: time, duration, time ranges, frame rates, and frame-based stepping. Designed around deterministic conversion between continuous time and discrete frame indices.

This makes it suitable for animation systems, simulations, and engine tooling where frame-accurate behavior matters.

Status

⚠️ Experimental / Work in Progress

The API is still evolving and may change significantly.

Features

  • no_std compatible
  • Time and Duration types
  • Frame rate representation
  • Time ranges and range operations
  • Deterministic frame <-> time conversion
  • Frame-based stepping utilities

Usage

std

tempa = "0.1.17"

no_std

tempa = { version = "0.1.17", default-features = false }

Example

// Create a frame stepper running at 60 FPS and a simple 10-second clip.
let rate = FrameRate::from_fps(60.0_f64);
let mut stepper = FrameStepper::<u32, f64>::new(rate);
let clip = TimeRange::new(Time::from_seconds(0.0_f64), Time::from_seconds(10.0_f64));

// Advance the playhead by 120 frames (2 seconds at 60 FPS).
stepper.step(120);
assert_eq!(stepper.current(), FrameIndex::new(120_u32));
assert_approx_eq_abs!(stepper.current_time().seconds(), 2.0_f64, 1e-12_f64);

// Convert explicitly between discrete frames and continuous time.
let frame: FrameIndex<u32> = Time::from_seconds(1.25_f64).to_frame(rate);
assert_eq!(frame, FrameIndex::new(75_u32));

let time = Time::from_frame(frame, rate);
assert_approx_eq_abs!(time.seconds(), 1.25_f64, 1e-12_f64);

// Seek to an arbitrary time. Times between frame boundaries are rounded
// down to the frame currently containing that instant.
stepper.seek_time(Time::from_seconds(2.75_f64));
assert_eq!(stepper.current(), FrameIndex::new(165_u32));
assert_approx_eq_abs!(stepper.current_time().seconds(), 2.75_f64, 1e-12_f64);

// Normalize the playhead position within the clip.
let u = clip.normalize_time(stepper.current_time());
assert_approx_eq_abs!(u, 0.275_f64, 1e-12_f64);

// Remap the same normalized position into another time range.
let outro = TimeRange::new(Time::from_seconds(8.0_f64), Time::from_seconds(10.0_f64));
let outro_time = clip.remap_time(stepper.current_time(), &outro);
assert_approx_eq_abs!(outro_time.seconds(), 8.55_f64, 1e-12_f64);

// Construct ranges directly from scalar seconds.
let window: TimeRange<f64> = (1.0..3.5).into();
assert_approx_eq_abs!(window.duration().seconds(), 2.5_f64, 1e-12_f64);

// Merge overlapping ranges, for example when combining timeline edits.
let a = TimeRange::new(Time::from_seconds(1.0_f64), Time::from_seconds(4.0_f64));
let b = TimeRange::new(Time::from_seconds(3.5_f64), Time::from_seconds(6.0_f64));
let merged = a.union(&b);
assert_eq!(merged, TimeRange::new(Time::from_seconds(1.0_f64), Time::from_seconds(6.0_f64)));

// Stepping past the beginning of the timeline saturates at frame zero.
stepper.step(-10_000);
assert_eq!(stepper.current(), FrameIndex::ZERO);
assert_approx_eq_abs!(stepper.current_time().seconds(), 0.0_f64, 1e-12_f64);

License

The Tempa project is licensed under either the Apache License, Version 2.0 or the MIT license, at your option.

See LICENSE-APACHE and LICENSE-MIT for details.

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A Rust library for working with time in animation and real-time systems.

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