Farben

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Colors In Depth ​

So you've seen [red] and [blue]. Those are great, but Farben supports a lot more than eight colors. Let's go deeper.

Foreground and Background ​

By default, every color tag applies to the foreground, which is the text itself. But you can explicitly target the background too using the bg: and fg: prefixes.

rust
cprintln!("[bg:red]Red background!");
cprintln!("[fg:white bg:blue]White text on a blue background.");
cprintln!("[bold fg:yellow bg:red]Chaotic but valid.");

TIP

[red] and [fg:red] are identical. The fg: prefix is just explicit, useful when combining foreground and background in the same bracket.

ANSI 256-Color Palette ​

Your terminal supports 256 colors. Access any of them with ansi(n) where n is a number from 0 to 255.

rust
cprintln!("[ansi(214)]This is a nice orange.");
cprintln!("[ansi(93)]Deep purple. My favorite.");
cprintln!("[bg:ansi(236)]Don't use black text on me.");

INFO

Not sure which number maps to which color? Look up an ANSI 256 color chart, there are plenty online.

RGB Colors ​

For full 24-bit color, use rgb(r,g,b) with values from 0 to 255.

rust
cprintln!("[rgb(255,128,0)]Orange, but uses unnecessary values. Do we really need RGB for this..?");
cprintln!("[rgb(0,200,100)]Look at that tree!");
cprintln!("[bold rgb(255,0,128)]Is it hot here?");
cprintln!("[fg:rgb(255,255,255) bg:rgb(30,30,30)]I'm light on the inside, dark on the outside.");

HSL Colors ​

Hue, Saturation, Lightness. Same syntax as CSS.

rust
cprintln!("[hsl(0,100,50)]Pure red.");
cprintln!("[hsl(120,100,50)]Pure green.");
cprintln!("[hsl(45,80,60)]A warm gold.");

HSV / HSB Colors ​

Hue, Saturation, Value (or Brightness).

rust
cprintln!("[hsv(0,100,100)]Pure red.");
cprintln!("[hsb(200,80,90)]Vivid sky blue.");

HWB Colors ​

Hue, Whiteness, Blackness.

rust
cprintln!("[hwb(0,0,0)]Pure red.");
cprintln!("[hwb(0,50,0)]Pink.");

CIE Lab / LCH Colors ​

Perceptually uniform color spaces.

rust
cprintln!("[lab(53,80,67)]Vivid red.");
cprintln!("[lch(50,30,270)]A blue hue.");

OKLCh Colors ​

A newer, more perceptually uniform variant.

rust
cprintln!("[oklch(0.6,0.15,280)]Cool purple.");

Hex Colors ​

Short and long hex notation.

rust
cprintln!("[#ff0000]Red via hex.");
cprintln!("[#f00]Shorthand hex red.");

Color Degradation ​

Farben automatically detects your terminal's color capabilities via COLORTERM and TERM environment variables. If your terminal does not support truecolor, Farben degrades RGB colors to the nearest ANSI 256 index or named color. This happens transparently. You write the same markup regardless of terminal capability.

Combining It All ​

All color formats work inside multi-tag brackets alongside emphasis styles.

rust
cprintln!("[bold bg:ansi(236) fg:rgb(255,200,0)]I'm a gold text on dark grey, I'm bold!");
cprintln!("[italic hsv(200,80,90)]HSL-inspired sky blue, italic.");
cprintln!("[underline #ff8800]Orange underlined text.");

The order of tags inside a bracket doesn't matter, Farben processes them all. But it's better to be sure if you're following the rules, hence why we go towards Conventions.

For a full reference of all color format syntax and validation rules, see the Advanced Color Formats guide.