# keyframe
A simple library for animation in Rust
[](https://crates.io/crates/keyframe)
[](https://crates.io/crates/keyframe)
[](https://docs.rs/keyframe)
## Features
* Several [easing functions](https://easings.net/en), including user-defined Bézier curves (like CSS [cubic-bezier](https://www.w3.org/TR/css-easing-1/#cubic-bezier-easing-functions)) and keyframable curves
* Animation sequences (like CSS [@keyframes](https://developer.mozilla.org/en-US/docs/Web/CSS/@keyframes))
* [mint](https://github.com/kvark/mint) integration for 2D/3D/4D support (points, rectangles, colors, etc)
## Usage
Tweening between two values is done with `keyframe::ease(function, from, to, time)`. `from` and `to` can be any type that implements `CanTween`, such as `f64` or `mint::Vector2`, while `time` needs to be a floating-point value between zero and one. `function` specifies the transition between `from` and `to` and is any type that implements `EasingFunction`.
`keyframe::AnimationSequence` can be used to create more complex animations that keep track of keyframes, time, etc. You can create animation sequences with the `keyframes![...]` macro, from an iterator or from a vector.
## Examples
An example visualizer is included in `examples/`. Run `cargo run --example visualizer --release` to start it. (ggez is really slow in debug mode!)
Tweening:
```rust
use keyframe::{ease, functions::EaseInOut};
fn example() -> f64 {
let a = 0.0;
let b = 2.0;
let time = 0.5;
ease(EaseInOut, a, b, time)
}
```
Animation sequences:
```rust
use keyframe::{keyframes, Keyframe, AnimationSequence};
fn example() {
// (value, time) or (value, time, function)
let mut sequence = keyframes![
(0.5, 0.0), // <-- EaseInOut used from 0.0 to 0.3
(1.5, 0.3, Linear), // <-- Linear used from 0.3 to 1.0
(2.5, 1.0) // <-- Easing function here is never used, since we're at the end
];
sequence.advance_by(0.65);
assert_eq!(sequence.now(), 2.0);
assert_eq!(sequence.duration(), 1.0);
}
```
Custom structures:
```rust
use keyframe::mint::Point2;
// This macro works with any structure as long as it only consists of types that implement "CanTween"
use keyframe_derive::CanTween;
#[derive(CanTween)]
struct MySubStructure {
a: f32
}
#[derive(CanTween)]
struct MyStructure {
a: f64,
b: Point2<f64>,
c: f32,
d: [MySubStructure; N] // Array length matching is guaranteed by the type system
}
// Also works with unnamed structures
#[derive(CanTween)]
struct UnnamedStructure(MyStructure, f64);
```