Luv

Tools for converting colours between sRGB, L*u*v* and LCh(uv) colour spaces and comparing differences in colour.

sRGB colors, for this crate at least, are considered to be composed of u8 values from 0 to 255, while L*u*v* colors are represented by its own struct that uses f32 values. The crate is biased towards sRGB thus it also assumes that L*u*v* uses D65 reference white point.

Usage

Converting single values

To convert a single value, use one of the functions

• luv::Luv::from_rgb(rgb: &[u8; 3]) -> Luv
• luv::Luv::from_rgba(rgba: &[u8; 4]) -> Luv (drops the fourth alpha byte)
• luv::Luv::to_rgb(&self) -> [u8; 3]

let pink = luv::Luv::from_rgb(&[253, 120, 138]);
assert_eq!(luv::Luv { l: 66.637695, u: 93.02938, v: 9.430316 }, pink);

Converting multiple values

To convert slices of values

• luv::rgbs_to_luvs(rgbs: &[[u8; 3]]) -> Vec<Luv>
• luv::luvs_to_rgbs(luvs: &[Luv]) -> Vec<[u8; 3]>
• luv::rgb_bytes_to_luvs(bytes: &[u8]) -> Vec<Luv>
• luv::luvs_to_rgb_bytes(luvs: &[Luv]) -> Vec<u8>

let rgbs = vec![
    [0xFF, 0x69, 0xB6],
    [0xE7, 0x00, 0x00],
    [0xFF, 0x8C, 0x00],
    [0xFF, 0xEF, 0x00],
    [0x00, 0x81, 0x1F],
    [0x00, 0xC1, 0xC1],
    [0x00, 0x44, 0xFF],
    [0x76, 0x00, 0x89],
];

let luvs = luv::rgbs_to_luvs(&rgbs);

use luv::rgb_bytes_to_luvs;

let rgbs = vec![
    0xFF, 0x69, 0xB6,
    0xE7, 0x00, 0x00,
    0xFF, 0x8C, 0x00,
    0xFF, 0xEF, 0x00,
    0x00, 0x81, 0x1F,
    0x00, 0xC1, 0xC1,
    0x00, 0x44, 0xFF,
    0x76, 0x00, 0x89,
];

let luvs = rgb_bytes_to_luvs(&rgbs);

Features

The crate defines an approx feature. If enabled, approximate equality as defined by approx crate will be implemented for the Luv and LCh types.

Other crates

The design — and to some degree code — of this crate has been based on the lab crate which provides routines for converting colours between sRGB, L*a*\b and LCh(ab) colour spaces.

For conversion between sRGB and XYZ colour spaces this crate relies on the srgb crate.