Farben

Appearance

Advanced Color Formats ​

Beyond named colors and basic RGB, Farben supports six additional color spaces: HSL, HSV (also known as HSB), HWB, Lab, LCH, and OKLCh. All of them accept optional spaces inside the parentheses and validate argument ranges.

HSL ​

Hue, Saturation, Lightness. Matches the CSS hsl() function.

[hsl(h, s, l)]
  • h: 0-360 (hue angle in degrees)
  • s: 0-100 (saturation percent)
  • l: 0-100 (lightness percent)
rust
use farben::prelude::*;

cprintln!("[hsl(0,100,50)]Pure red via HSL.");
cprintln!("[hsl(120,100,50)]Pure green via HSL.");
cprintln!("[hsl(240,100,50)]Pure blue via HSL.");
cprintln!("[hsl(45,80,60)]A warm golden color.");

HSV / HSB ​

Hue, Saturation, Value (also known as Hue, Saturation, Brightness). Both names work interchangeably.

[hsv(h, s, v)] or [hsb(h, s, b)]
  • h: 0-360 (hue angle in degrees)
  • s: 0-100 (saturation percent)
  • v/b: 0-100 (value/brightness percent)
rust
use farben::prelude::*;

cprintln!("[hsv(0,100,100)]Pure red via HSV.");
cprintln!("[hsv(200,80,90)]A vivid sky blue.");
cprintln!("[hsb(300,60,80)]A muted magenta via HSB.");

HWB ​

Hue, Whiteness, Blackness. An intuitive model: start with a pure hue, add white, add black.

[hwb(h, w, b)]
  • h: 0-360 (hue angle in degrees)
  • w: 0-100 (whiteness percent)
  • b: 0-100 (blackness percent)
  • Constraint: w + b must not exceed 100
rust
use farben::prelude::*;

cprintln!("[hwb(0,0,0)]Pure red.");
cprintln!("[hwb(0,50,0)]Pink (red + white).");
cprintln!("[hwb(0,0,50)]Dark red (red + black).");
cprintln!("[hwb(200,30,20)]A muted teal.");

Lab ​

CIE L*a*b* is a perceptually uniform color space. L* is lightness, a* is green-red, b* is blue-yellow.

[lab(l, a, b)]
  • l: 0-100 (lightness)
  • a: -128 to 127 (green to red)
  • b: -128 to 127 (blue to yellow)
rust
use farben::prelude::*;

cprintln!("[lab(0,0,0)]Black.");
cprintln!("[lab(100,0,0)]White.");
cprintln!("[lab(53,80,67)]A vivid red.");
cprintln!("[lab(50,-50,0)]A cool green.");

LCH ​

CIE L*C*h* (Lightness, Chroma, Hue) is a cylindrical representation of Lab.

[lch(l, c, h)]
  • l: 0-100 (lightness)
  • c: 0-150 (chroma / saturation)
  • h: 0-360 (hue angle in degrees)
rust
use farben::prelude::*;

cprintln!("[lch(50,30,270)]A blue hue.");
cprintln!("[lch(70,50,45)]A warm orange.");

OKLCh ​

A newer, more perceptually uniform variant of LCH. Uses the same cylindrical model but with a different lightness scale.

[oklch(l, c, h)]
  • l: 0.0-1.0 (lightness, as a decimal fraction)
  • c: 0.0-0.4 (chroma / saturation)
  • h: 0-360 (hue angle in degrees)
rust
use farben::prelude::*;

cprintln!("[oklch(0.6,0.15,280)]A cool purple.");
cprintln!("[oklch(0.8,0.2,120)]A vibrant green.");

Hex Colors ​

Short and long hex notation.

[#rgb] or [#rrggbb]

3-digit shorthand (#rgb) doubles each channel: #f00 becomes #ff0000.

rust
use farben::prelude::*;

cprintln!("[#ff0000]Pure red via hex.");
cprintln!("[#00ff00]Pure green via hex.");
cprintln!("[#f00]Shorthand hex red.");
cprintln!("[#0f0]Shorthand hex green.");
cprintln!("[#ff8800]A warm orange via hex.");

Validation ​

All color formats validate their arguments. If a value is out of range or the wrong number of arguments is given, color() panics and try_color() returns an error:

rust
use farben::try_color;

// Invalid: H out of range
assert!(try_color("[hsl(400,50,50)]text").is_err());

// Invalid: missing argument
assert!(try_color("[hsl(100,50)]text").is_err());

// Invalid: w + b > 100
assert!(try_color("[hwb(0,60,60)]text").is_err());

// Invalid: hex with wrong length
assert!(try_color("[#ff00]text").is_err());

// Invalid: hex with non-hex characters
assert!(try_color("[#xyz]text").is_err());

Summary ​

FormatSyntaxRanges
HSL[hsl(h,s,l)]H:0-360, S:0-100, L:0-100
HSV / HSB[hsv(h,s,v)] / [hsb(h,s,b)]H:0-360, S:0-100, V/B:0-100
HWB[hwb(h,w,b)]H:0-360, W:0-100, B:0-100, W+B<=100
Lab[lab(l,a,b)]L:0-100, A:-128-127, B:-128-127
LCH[lch(l,c,h)]L:0-100, C:0-150, H:0-360
OKLCh[oklch(l,c,h)]L:0.0-1.0, C:0.0-0.4, H:0-360
Hex[#rgb] / [#rrggbb]0-9, a-f, A-F