animate_core/mode/
alternate.rs

1use crate::macros::impl_ops;
2use crate::{Animate, AnimateState, FRAME_TIME, IS_ANIMATING, Lerp};
3use std::sync::atomic::Ordering;
4
5#[derive(Debug)]
6pub struct Alternate<T, E, I>(pub(crate) AnimateState<T, E, I>)
7where
8    T: Lerp + PartialEq,
9    E: Fn(f64) -> f64,
10    I: Fn(&T, &T, f64) -> T;
11
12impl<T, E, I> Alternate<T, E, I>
13where
14    T: Lerp + PartialEq + Default,
15    E: Fn(f64) -> f64,
16    I: Fn(&T, &T, f64) -> T,
17{
18    pub fn new(initial: T, duration: f64, easing: E, interp: I) -> Self {
19        Self(AnimateState::new(initial, duration, easing, interp))
20    }
21}
22
23impl<T, E, I> Animate for Alternate<T, E, I>
24where
25    T: Lerp + PartialEq + Default,
26    E: Fn(f64) -> f64,
27    I: Fn(&T, &T, f64) -> T,
28{
29    type Value = T;
30
31    fn update(&mut self) {
32        let inner = &mut self.0.inner;
33
34        if inner.pending {
35            inner.start = std::mem::take(&mut inner.current);
36            inner.pending = false;
37        }
38
39        if let Some(start_t) = inner.started_at {
40            if self.0.duration > 0.0 {
41                let now = FRAME_TIME.load(Ordering::Relaxed);
42                let elapsed = now.saturating_sub(start_t) as f64;
43                let cycle = (elapsed / self.0.duration) as u64;
44                let t_raw = (elapsed % self.0.duration) / self.0.duration;
45                let t = if cycle % 2 == 0 { t_raw } else { 1.0 - t_raw };
46
47                inner.current = (self.0.interp)(&inner.start, &inner.target, (self.0.easing)(t));
48            }
49            IS_ANIMATING.store(true, Ordering::Relaxed);
50        }
51    }
52
53    fn get(&self) -> &T {
54        &self.0.inner.current
55    }
56
57    fn set(&mut self, target: T) {
58        let now = FRAME_TIME.load(Ordering::Relaxed);
59        let inner = &mut self.0.inner;
60
61        inner.target = target;
62        inner.started_at = Some(now);
63        inner.pending = true;
64    }
65
66    fn target(&self) -> &T {
67        &self.0.inner.target
68    }
69}
70
71impl_ops!(Alternate);
animate_core/mode/alternate.rs

animate_core/mode/
alternate.rs
