telar-motion-core 0.1.1

Signal-backed animation engine for Telar: tweens and springs driven by a central frame ticker.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68

use std::time::Duration;

use crate::easing::Easing;

/// A time-based interpolation over a fixed `duration` shaped by `easing`.
#[derive(Debug, Clone, Copy, PartialEq)]
pub struct Tween {
    pub duration: Duration,
    pub easing: Easing,
}

/// A physical spring parameterized by raw `stiffness`, `damping`, and `mass`.
#[derive(Debug, Clone, Copy, PartialEq)]
pub struct Spring {
    pub stiffness: f32,
    pub damping: f32,
    pub mass: f32,
}

/// The motion model backing an [`crate::Animated`] value.
#[derive(Debug, Clone, Copy, PartialEq)]
pub enum Curve {
    Tween(Tween),
    Spring(Spring),
}

/// Build a [`Tween`] from a duration and easing.
pub fn tween(duration: Duration, easing: Easing) -> Tween {
    Tween { duration, easing }
}

/// Build a [`Spring`] from stiffness and damping; mass defaults to 1.0.
pub fn spring(stiffness: f32, damping: f32) -> Spring {
    Spring {
        stiffness,
        damping,
        mass: 1.0,
    }
}

impl Spring {
    /// Soft settle with essentially no overshoot; scale mirrors the near-critical spring(170, 26) used for the sandbox theme-color transition.
    pub fn gentle() -> Spring {
        spring(120.0, 14.0)
    }

    /// Fast, firm settle for interactive feedback (button presses, toggles).
    pub fn snappy() -> Spring {
        spring(210.0, 20.0)
    }

    /// Visible overshoot before settling; scale mirrors the underdamped spring(170, 12) used for the sandbox scale demo.
    pub fn bouncy() -> Spring {
        spring(180.0, 12.0)
    }
}

impl From<Tween> for Curve {
    fn from(t: Tween) -> Self {
        Curve::Tween(t)
    }
}

impl From<Spring> for Curve {
    fn from(s: Spring) -> Self {
        Curve::Spring(s)
    }
}