chromashift/
srgb.rs

1use crate::LinearRgb;
2use core::fmt;
3
4/// An RGB colour space with defined chromacities.
5/// The components are:
6/// - Red - a number between 0 and 255
7/// - Blue - a number between 0 and 255
8/// - Green - a number between 0 and 255
9/// - Alpha - a number between 0.0 and 100.0
10#[derive(Debug, Clone, Copy, PartialEq)]
11pub struct Srgb {
12	pub red: u8,
13	pub green: u8,
14	pub blue: u8,
15	pub alpha: f32,
16}
17
18impl Srgb {
19	pub fn new(red: u8, green: u8, blue: u8, alpha: f32) -> Self {
20		Self { red, green, blue, alpha: alpha.clamp(0.0, 100.0) }
21	}
22}
23
24impl fmt::Display for Srgb {
25	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
26		let Self { red, green, blue, alpha } = self;
27		write!(f, "rgb({red} {green} {blue}")?;
28		if *alpha < 100.0 {
29			write!(f, " / {alpha}%")?;
30		}
31		write!(f, ")")
32	}
33}
34
35fn linear(c: f64) -> f64 {
36	if c > 0.04045 { ((c + 0.055) / 1.055).powf(2.4) } else { c / 12.92 }
37}
38
39fn gamma(u: f64) -> f64 {
40	if u <= 0.0031308 { u * 12.92 } else { 1.055 * u.powf(1.0 / 2.4) - 0.055 }
41}
42
43fn clamp01(value: f64) -> f64 {
44	value.clamp(0.0, 1.0)
45}
46
47impl From<Srgb> for LinearRgb {
48	fn from(value: Srgb) -> Self {
49		let Srgb { red, green, blue, alpha } = value;
50		LinearRgb::new(linear(red as f64 / 255.0), linear(green as f64 / 255.0), linear(blue as f64 / 255.0), alpha)
51	}
52}
53
54impl From<LinearRgb> for Srgb {
55	fn from(value: LinearRgb) -> Self {
56		let LinearRgb { red, green, blue, alpha } = value;
57		Srgb::new(
58			(gamma(clamp01(red)) * 255.0).round() as u8,
59			(gamma(clamp01(green)) * 255.0).round() as u8,
60			(gamma(clamp01(blue)) * 255.0).round() as u8,
61			alpha,
62		)
63	}
64}
65
66#[cfg(feature = "anstyle")]
67impl From<Srgb> for anstyle::RgbColor {
68	fn from(value: Srgb) -> Self {
69		anstyle::RgbColor(value.red, value.green, value.blue)
70	}
71}
72
73#[cfg(feature = "anstyle")]
74impl From<anstyle::RgbColor> for Srgb {
75	fn from(value: anstyle::RgbColor) -> Self {
76		Srgb::new(value.0, value.1, value.2, 100.0)
77	}
78}
chromashift/srgb.rs

chromashift/
srgb.rs
