# Lilt
[](https://codecov.io/github/ejjonny/lilt)
[](https://crates.io/crates/lilt)
[](https://crates.io/crates/lilt)
[](https://github.com/lilt/blob/master/LICENSE)
A simple, dependency free library for running interruptable, transition based animations as a function of time.
This library only implements animations & would be most useful along with a GUI library that can do GUI things (like [iced](https://github.com/iced-rs/iced)).
## Getting Started
### Define
Embed the state you want to animate in an `Animated` struct.
```rust
struct MyViewState {
toggle: Animated,
}
```
When you initialize your view state - define the initial state & configure the animation to your liking.
```rust
let mut state = MyViewState {
toggle: Animated::new(false)
.duration(300.)
.easing(Easing::EaseOut)
.delay(30.)
.repeat(3),
};
```
### Transition
When your state needs an update, call the `transition` function on your animated state, passing the current time.
```rust
let now = std::time::Instant::now();
state
.toggle
.transition(!state.animated_toggle.value, now);
```
### Render
While rendering a view based on your state - use the `animate` function on your state to get the interpolated value for the current frame.
```rust
let now = std::time::Instant::now();
// The wrapped value can be used to interpolate any values that implement `Interpolable`
let animated_width = self.toggle.animate_bool(100., 500., now);
// If the wrapped value itself is `Interpolable`, it can easily be interpolated in place
let animated_width = self.width.animate_wrapped(now);
// There are plenty of `animate` methods for interpolating things based on the wrapped value.
```
### What's the point?
lilt emerged from the need for ELM compatible / reactive animations.
The animations modeled by this library don't require periodic mutation like a 'tick' function - all interim states of the animation are predefined when 'transition' is called, & then accessed while rendering based on the current time.
lilt animations are fully independent of frame rate or tick frequency & only need to be computed if they're used during rendering.
## [Examples](examples/)
