apcach-rs

Rust port of apcach, a color calculator for composing colors with consistent APCA or WCAG contrast.

The crate works in OKLCH and can target both sRGB and Display-P3 output.

Install

Add the crate to Cargo.toml:

[dependencies]
apcach-rs = "0.1"

In Rust code, import it as apcach_rs.

Example

use apcach_rs::{apcach, to_css, Chroma, ColorSpace, CssFormat};

fn main() -> Result<(), apcach_rs::Error> {
    let color = apcach(70.0, Chroma::Fixed(0.15), 150.0, 100.0, ColorSpace::Srgb)?;

    assert_eq!(to_css(color, CssFormat::Hex)?.len(), 7);
    Ok(())
}

Compose Colors

White background shorthand:

use apcach_rs::{apcach, Chroma, ColorSpace};

let color = apcach(60.0, Chroma::Fixed(0.2), 145.0, 100.0, ColorSpace::Srgb)?;

Foreground on a custom background:

use apcach_rs::{apcach, cr_to_bg, Chroma, Color, ColorSpace, ContrastModel, SearchDirection};

let color = apcach(
    cr_to_bg(
        Color::srgb(0.91, 0.91, 0.91),
        60.0,
        ContrastModel::Apca,
        SearchDirection::Auto,
    ),
    Chroma::Fixed(0.2),
    145.0,
    100.0,
    ColorSpace::Srgb,
)?;

Maximum chroma search:

use apcach_rs::{apcach, cr_to_bg_white, max_chroma, ColorSpace, ContrastModel, SearchDirection};

let color = apcach(
    cr_to_bg_white(70.0, ContrastModel::Apca, SearchDirection::Auto),
    max_chroma(),
    200.0,
    100.0,
    ColorSpace::Srgb,
)?;

Convert To CSS

use apcach_rs::{apcach, to_css, Chroma, ColorSpace, CssFormat};

let color = apcach(70.0, Chroma::Fixed(0.15), 150.0, 100.0, ColorSpace::Srgb)?;

let oklch = to_css(color, CssFormat::Oklch)?;
let hex = to_css(color, CssFormat::Hex)?;
let rgb = to_css(color, CssFormat::Rgb)?;
let p3 = to_css(color, CssFormat::P3)?;

Supported CSS output formats:

• CssFormat::Oklch
• CssFormat::Rgb
• CssFormat::Hex
• CssFormat::P3
• CssFormat::FigmaP3

API Overview

Core composition and conversion:

• apcach
• calc_contrast
• to_css

Contrast configuration helpers:

• cr_to_bg
• cr_to_bg_white
• cr_to_bg_black
• cr_to_fg
• cr_to_fg_white
• cr_to_fg_black

Color adjustment helpers:

• set_contrast
• map_contrast
• set_chroma
• map_chroma
• set_hue
• map_hue

Chroma helpers:

• max_chroma
• max_chroma_capped

Key public types:

• ApcachColor
• Chroma
• Color
• ColorSpace
• ContrastConfig
• ContrastInput
• ContrastModel
• CssFormat
• Error
• SearchDirection

License

MIT