animato_spring/
config.rs

1//! [`SpringConfig`] — parameters that control spring behaviour.
2
3/// Configuration for a damped harmonic oscillator spring.
4///
5/// Use one of the named presets for common feels, or tune the parameters directly.
6///
7/// # Presets
8///
9/// | Preset | Stiffness | Damping | Feel |
10/// |--------|-----------|---------|------|
11/// | `gentle()` | 60 | 14 | Slow, soft |
12/// | `wobbly()` | 180 | 12 | Bouncy, playful |
13/// | `stiff()` | 210 | 20 | Fast, firm |
14/// | `slow()` | 37 | 14 | Very slow, lazy |
15/// | `snappy()` | 300 | 30 | Near-instant |
16///
17/// # Example
18///
19/// ```rust
20/// use animato_spring::SpringConfig;
21///
22/// let cfg = SpringConfig::wobbly();
23/// assert_eq!(cfg.stiffness, 180.0);
24/// ```
25#[derive(Clone, Debug)]
26#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
27pub struct SpringConfig {
28    /// Restoring force. Higher = snappier. Default: `100.0`.
29    pub stiffness: f32,
30    /// Resistance to motion. Higher = less bouncy. Default: `10.0`.
31    pub damping: f32,
32    /// Mass of the simulated object. Default: `1.0`.
33    pub mass: f32,
34    /// Settle threshold — spring is considered at rest when both
35    /// `|position - target| < epsilon` and `|velocity| < epsilon`. Default: `0.001`.
36    pub epsilon: f32,
37}
38
39impl Default for SpringConfig {
40    fn default() -> Self {
41        Self {
42            stiffness: 100.0,
43            damping: 10.0,
44            mass: 1.0,
45            epsilon: 0.001,
46        }
47    }
48}
49
50impl SpringConfig {
51    /// Slow, soft spring — good for subtle UI elements.
52    pub fn gentle() -> Self {
53        Self {
54            stiffness: 60.0,
55            damping: 14.0,
56            mass: 1.0,
57            epsilon: 0.001,
58        }
59    }
60
61    /// Bouncy, playful spring — great for icons and interactive elements.
62    pub fn wobbly() -> Self {
63        Self {
64            stiffness: 180.0,
65            damping: 12.0,
66            mass: 1.0,
67            epsilon: 0.001,
68        }
69    }
70
71    /// Fast, firm spring — good for panels and drawers.
72    pub fn stiff() -> Self {
73        Self {
74            stiffness: 210.0,
75            damping: 20.0,
76            mass: 1.0,
77            epsilon: 0.001,
78        }
79    }
80
81    /// Very slow, lazy spring — good for background animations.
82    pub fn slow() -> Self {
83        Self {
84            stiffness: 37.0,
85            damping: 14.0,
86            mass: 1.0,
87            epsilon: 0.001,
88        }
89    }
90
91    /// Near-instant response — for time-critical feedback.
92    pub fn snappy() -> Self {
93        Self {
94            stiffness: 300.0,
95            damping: 30.0,
96            mass: 1.0,
97            epsilon: 0.001,
98        }
99    }
100}
animato_spring/config.rs

animato_spring/
config.rs
