smart_leds/
lib.rs

1//! # Smart Leds
2//!
3//! Smart leds is a collection of crates to use smart leds on embedded devices with rust.
4//!
5//! Examples of smart leds include the popular WS2812 (also called Neopixel),
6//! APA102 (DotStar) and other leds, which can be individually adressed.
7//!
8//! Other driver crates implement these indivdual interfaces and should be used in
9//! tandem with this crate. This crate provides various convenience utilities
10//! for end users.
11//!
12//! Other crates should depended on the
13//! [smart-leds-trait](https://crates.io/crates/smart-leds-trait) crate, which
14//! (should) experience less breaking changes
15#![no_std]
16
17pub mod colors;
18pub mod hsv;
19
20pub use smart_leds_trait::*;
21
22/// An iterator that provides brightness reduction
23///
24/// Please be aware that using this after gamma correction the colours doesn't
25/// work right.
26pub struct Brightness<I> {
27    iter: I,
28    brightness: u8,
29}
30
31impl<I> Iterator for Brightness<I>
32where
33    I: Iterator<Item = RGB8>,
34{
35    type Item = RGB8;
36
37    fn next(&mut self) -> Option<RGB8> {
38        self.iter.next().map(|a| RGB8 {
39            r: (a.r as u16 * (self.brightness as u16 + 1) / 256) as u8,
40            g: (a.g as u16 * (self.brightness as u16 + 1) / 256) as u8,
41            b: (a.b as u16 * (self.brightness as u16 + 1) / 256) as u8,
42        })
43    }
44}
45
46/// Pass your iterator into this function to get reduced brightness
47pub fn brightness<I>(iter: I, brightness: u8) -> Brightness<I>
48where
49    I: Iterator<Item = RGB8>,
50{
51    Brightness { iter, brightness }
52}
53
54/// An iterator that provides gamma correction.
55/// Makes the colour distribution non-linear, to match your eyes' perception
56/// In other words, makes orange look orange.
57/// If using in combination with a brightness reduction, apply the gamma
58/// correction first, then the brightness reduction
59/// ie: brightness(gamma(data.iter().cloned()), 32)
60pub struct Gamma<I> {
61    iter: I,
62}
63
64impl<I> Iterator for Gamma<I>
65where
66    I: Iterator<Item = RGB8>,
67{
68    type Item = RGB8;
69
70    fn next(&mut self) -> Option<RGB8> {
71        // This table remaps linear input values
72        // (the numbers we’d like to use; e.g. 127 = half brightness)
73        // to nonlinear gamma-corrected output values
74        // (numbers producing the desired effect on the LED;
75        // e.g. 36 = half brightness).
76        //
77        // It's generated using the gamma.py script
78        const GAMMA8: [u8; 256] = [
79            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1,
80            1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 4, 4,
81            4, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 9, 9, 9, 10, 10, 10, 11, 11, 11,
82            12, 12, 13, 13, 13, 14, 14, 15, 15, 16, 16, 17, 17, 18, 18, 19, 19, 20, 20, 21, 21, 22,
83            22, 23, 24, 24, 25, 25, 26, 27, 27, 28, 29, 29, 30, 31, 32, 32, 33, 34, 35, 35, 36, 37,
84            38, 39, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 50, 51, 52, 54, 55, 56, 57, 58,
85            59, 60, 61, 62, 63, 64, 66, 67, 68, 69, 70, 72, 73, 74, 75, 77, 78, 79, 81, 82, 83, 85,
86            86, 87, 89, 90, 92, 93, 95, 96, 98, 99, 101, 102, 104, 105, 107, 109, 110, 112, 114,
87            115, 117, 119, 120, 122, 124, 126, 127, 129, 131, 133, 135, 137, 138, 140, 142, 144,
88            146, 148, 150, 152, 154, 156, 158, 160, 162, 164, 167, 169, 171, 173, 175, 177, 180,
89            182, 184, 186, 189, 191, 193, 196, 198, 200, 203, 205, 208, 210, 213, 215, 218, 220,
90            223, 225, 228, 231, 233, 236, 239, 241, 244, 247, 249, 252, 255,
91        ];
92        self.iter.next().map(|a| RGB8 {
93            r: GAMMA8[a.r as usize],
94            g: GAMMA8[a.g as usize],
95            b: GAMMA8[a.b as usize],
96        })
97    }
98}
99
100/// Pass your iterator into this function to get corrected gamma
101pub fn gamma<I>(iter: I) -> Gamma<I>
102where
103    I: Iterator<Item = RGB8>,
104{
105    Gamma { iter }
106}
smart_leds/lib.rs

smart_leds/
lib.rs
