Struct ColorScheme 

pub struct ColorScheme {

    pub primary: Color,
    pub on_primary: Color,
    pub primary_container: Color,
    pub on_primary_container: Color,
    pub primary_fixed: Color,
    pub primary_fixed_dim: Color,
    pub on_primary_fixed: Color,
    pub on_primary_fixed_variant: Color,
    pub secondary: Color,
    pub on_secondary: Color,
    pub secondary_container: Color,
    pub on_secondary_container: Color,
    pub secondary_fixed: Color,
    pub secondary_fixed_dim: Color,
    pub on_secondary_fixed: Color,
    pub on_secondary_fixed_variant: Color,
    pub tertiary: Color,
    pub on_tertiary: Color,
    pub tertiary_container: Color,
    pub on_tertiary_container: Color,
    pub tertiary_fixed: Color,
    pub tertiary_fixed_dim: Color,
    pub on_tertiary_fixed: Color,
    pub on_tertiary_fixed_variant: Color,
    pub error: Color,
    pub on_error: Color,
    pub error_container: Color,
    pub on_error_container: Color,
    pub surface: Color,
    pub on_surface: Color,
    pub on_surface_variant: Color,
    pub surface_dim: Color,
    pub surface_bright: Color,
    pub surface_container_lowest: Color,
    pub surface_container_low: Color,
    pub surface_container: Color,
    pub surface_container_high: Color,
    pub surface_container_highest: Color,
    pub outline: Color,
    pub outline_variant: Color,
    pub shadow: Color,
    pub scrim: Color,
    pub inverse_surface: Color,
    pub inverse_on_surface: Color,
    pub inverse_primary: Color,
    pub surface_tint: Color,
}

A full set of color roles for one brightness (light or dark), on Material 3’s role vocabulary.

46 non-deprecated roles (see module docs for the deprecated 3). This crate constructs one table, the language-free ColorScheme::neutral_light/ColorScheme::neutral_dark pair; a design system fills the same fields from its own source values in its own crate. Fields are normally opaque Colors — channel-appropriate translucency (e.g. for scrims) is applied by the widget/scene layer, not stored here — but a design system whose real token is itself translucent may store the non-opaque value rather than misrepresent it.

Fields

primary: Color

on_primary: Color

primary_container: Color

on_primary_container: Color

primary_fixed: Color

primary_fixed_dim: Color

on_primary_fixed: Color

on_primary_fixed_variant: Color

secondary: Color

on_secondary: Color

secondary_container: Color

on_secondary_container: Color

secondary_fixed: Color

secondary_fixed_dim: Color

on_secondary_fixed: Color

on_secondary_fixed_variant: Color

tertiary: Color

on_tertiary: Color

tertiary_container: Color

on_tertiary_container: Color

tertiary_fixed: Color

tertiary_fixed_dim: Color

on_tertiary_fixed: Color

on_tertiary_fixed_variant: Color

error: Color

on_error: Color

error_container: Color

on_error_container: Color

surface: Color

on_surface: Color

on_surface_variant: Color

surface_dim: Color

surface_bright: Color

surface_container_lowest: Color

surface_container_low: Color

surface_container: Color

surface_container_high: Color

surface_container_highest: Color

outline: Color

outline_variant: Color

shadow: Color

scrim: Color

inverse_surface: Color

inverse_on_surface: Color

inverse_primary: Color

surface_tint: Color

Implementations

impl ColorScheme

pub fn with_accent(self, accent: Color) -> Self

Replace the accent family from one seed color, Glyph-style.

Swaps exactly four roles: primary, on_primary, primary_container, and on_primary_container. All other 42 fields remain unchanged.

• primary: set to the provided accent color.
• on_primary: selected by relative luminance (WCAG contrast ratio ≥ 4.5:1 preferred) — prefer white if the accent is dark enough, else dark ink. A simple luminance threshold is used (see docs below).
• primary_container: an alpha-wash of the accent at 10% opacity, flattened over the scheme’s surface color to opaque.
• on_primary_container: set to the provided accent color (same as primary).

Luminance and Contrast

on_primary is determined by picking the ink that provides better contrast against the accent. Luminance is calculated via the WCAG relative luminance formula: L = 0.2126*R + 0.7152*G + 0.0722*B (after linearizing each channel from sRGB). If the accent’s luminance is below 0.5 (midpoint), white is preferred; otherwise, dark ink is preferred. This simple threshold provides acceptable contrast for most colors and avoids the overhead of computing the full contrast ratio (though a more precise contrast-ratio calculation could replace this later).

Works with Any Scheme

This method works on any ColorScheme — the neutral ramp below or any design system’s own table — without design-language branching.

Example

use peniko::Color;
use frust_theme::color::ColorScheme;

let base = ColorScheme::neutral_dark();
let red = Color::from_rgb8(0xFF, 0x00, 0x00);
let accent_scheme = base.with_accent(red);

assert_eq!(accent_scheme.primary, red);
assert_eq!(accent_scheme.on_primary_container, red);
// All other roles remain unchanged from the base scheme.

pub const fn neutral_light() -> Self

The neutral, design-language-free light ColorScheme: a plain achromatic surface/on-surface ramp, plus one restrained slate-blue accent filling the primary family — every other role (secondary/tertiary) stays gray too, since “neutral” means one accent, not a second or third hue. See crate::theme::Theme::neutral’s module docs for the design intent (“deliberately plain, not half-finished”).

Frust-authored, not sourced from any third-party design system — there is no external spec to cite here; values are chosen for legible contrast against their paired ink role (see ColorScheme::neutral_dark’s doc comment for the contrast rationale, verified by neutral_surface_on_surface_contrast_is_legible in this module’s tests). error/on_error/error_container/on_error_container are the one exception kept in real red — a functional/semantic signal (danger/destructive state), not a “look”, the same reasoning crate::theme::Theme::neutral uses to still attach crate::status::StatusPalette::neutral rather than a grayscale status set.

pub const fn neutral_dark() -> Self

The neutral, design-language-free dark ColorScheme — the dark-mode mirror of ColorScheme::neutral_light; see that constructor’s doc comment for the design rationale.

Contrast check (verified in this module’s tests): surface (#121212) against on_surface (#F2F2F2) is ~16.7:1, and ColorScheme::neutral_light’s equivalent pair is ~16.7:1 too — both far past the WCAG AA 4.5:1 normal-text floor.

Trait Implementations

impl Clone for ColorScheme

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for ColorScheme

impl Debug for ColorScheme

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for ColorScheme

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for ColorScheme