1# llimphi-motion
2
3Simple animation over Llimphi's Elm loop.
4
5Llimphi is pure Elm: `update(msg) -> model`. To animate a value over time (an
6alpha rising from 0 to 1, a position sliding) the app keeps a `Tween` in its
7model and asks the `Handle` to dispatch a `Msg::Tick` periodically (every ~16 ms)
8until the animation ends. Each `update` reads `tween.value()` and the `view`
9paints it.
10
11This crate is deliberately tiny:
12
13- `Lerp` — generic linear interpolation (impls for `f32`, `(f32, f32)` and
14 `Color`).
15- `Tween` — timed interpolation with easing between two values.
16- `animate` — a helper that starts a self-sufficient tick loop over a `Handle`.
17
18The canonical durations and easings live in `llimphi_theme::motion`.
19
20## Typical pattern
21
22```ignore
23use llimphi_motion::{Tween, animate};
24use llimphi_theme::motion;
25
26enum Msg { ToastShow, Tick, ToastHidden }
27struct Model { toast_alpha: Tween<f32> }
28
29// update:
30Msg::ToastShow => {
31 model.toast_alpha = Tween::new(0.0, 1.0, motion::NORMAL, motion::ease_out_cubic);
32 animate(handle, motion::NORMAL, || Msg::Tick);
33 model
34}
35Msg::Tick => {
36 // The internal loop ends by itself once the tween is done;
37 // the `view` already reads the current alpha.
38 model
39}
40
41// view:
42toast_view().alpha(model.toast_alpha.value())
43```
44
45---
46
47Part of **llimphi** — see [llimphi](../README.md).
README.md
llimphi-motion
Simple animation over Llimphi's Elm loop.
Llimphi is pure Elm: update(msg) -> model. To animate a value over time (an
alpha rising from 0 to 1, a position sliding) the app keeps a Tween in its
model and asks the Handle to dispatch a Msg::Tick periodically (every ~16 ms)
until the animation ends. Each update reads tween.value() and the view
paints it.
This crate is deliberately tiny:
Lerp — generic linear interpolation (impls for f32, (f32, f32) and
Color).Tween — timed interpolation with easing between two values.animate — a helper that starts a self-sufficient tick loop over a Handle.
The canonical durations and easings live in llimphi_theme::motion.
Typical pattern
use llimphi_motion::{Tween, animate};
use llimphi_theme::motion;
enum Msg { ToastShow, Tick, ToastHidden }
struct Model { toast_alpha: Tween<f32> }
// update:
Msg::ToastShow => {
model.toast_alpha = Tween::new(0.0, 1.0, motion::NORMAL, motion::ease_out_cubic);
animate(handle, motion::NORMAL, || Msg::Tick);
model
}
Msg::Tick => {
// The internal loop ends by itself once the tween is done;
// the `view` already reads the current alpha.
model
}
// view:
toast_view().alpha(model.toast_alpha.value())
Part of llimphi — see llimphi.