tween is an std-optional tweening library, designed for use in games and animations.
This trait exports a trait Tween, a variety of structs which implement common tweens (such as Elastic, Quart, etc), and two Tweeners, which wrap around tweens, allowing users to drive them trivially.
First, tweens are simple to create:
```rust use tween::SineIn;
let range = 0.0..=200.0; let duration = 60;
let mut sinein = SineIn::new(range, duration); let _value0 = sinein.run(0); let value1 = sinein.run(1); let value2 = sinein.run(2); let value3 = sinein.run(3); ```
Notice how we work over a RangeInclusive to provide values.
However, as the above example shows, it's more typical that you'll want to simply drive a tween over time, rather than giving arbitrary times within a duration.
For that, we use tweeners, which come in two kinds: Tweener and FixedTweener. For both, users provide deltas, rather than arbitrary times. A FixedTweener uses just one delta (appropriate in a game engine with a Fixed Update pipeline), whereas a Tweener can take a fixed delta.
```rust use tween::{SineIn, FixedTweener};
let range = 0.0..=200.0; let duration = 60;
let sinein = SineIn::new(range, duration); let delta = 1; let mut sineintweener = FixedTweener::new(sinein, delta);
let value0: Option
// we can finish off the tweener by using the iterator interface.
// we only use &mut here to demonstrate the None after this loop, you can just
// take it by value like normal.
for value in &mut sineintweener {
// FixedTweener provides an iterator interface
}
assert!(sineintweener.next().is_none()); ```
This library uses std with the default feature std. Disable default features, and enable libm, for a no-std experience. (We need to use libm for the floating point math).
This library uses generics heavily. There are two core generics used: TweenValue and TweenTime. All built-in numeric types implement both traits. For your own code, you can implement either trait. For example, you could easily implement TweenValue for your favorite math library.