roundel/theme

The theme (R4, R5): one map from token to style, flown once for the whole program.

import { rgb256, toOklab, audit, … } from 'roundel/theme';

FunctionsCopy Anchor Link

auditCopy Anchor Link

Every token's verdict, as data — without throwing.

function audit(theme?: Theme): ThemeFinding[];

Returns ThemeFinding[]

flyCopy Anchor Link

Fly the theme: decide the colour level from the runtime once, check every hex token against the ground, and set what the tokens paint from now on. Call it at startup, with { json } when the run was asked for --json; a later call replaces the theme.

function fly(theme: Theme, rt: Runtime, opts?: ModeOptions): void;

Returns void

rgb256Copy Anchor Link

The sRGB of a 256-palette index, which is ansi256 run backwards. Defined for 16–255 only, and that is the whole reason this check is possible: entries 0–15 are the user's terminal theme and entries 16–255 are not. Exported because it is the only honest way to ask "what will the terminal actually paint", which is a question a caller checking its own theme has as much right to ask as fly() does. The 6×6×6 cube and the 24-step grey ramp are the xterm values every terminal ships and none of them themes, so a contrast number over them is measured rather than invented — which is exactly what contrast.ts says cannot be done for the basic sixteen. ansi256 never returns below 16, so every paint it produces is knowable.

function rgb256(index: number): Hex;

Returns Hex

toOklabCopy Anchor Link

sRGB 0–255 to OKLab. Björn Ottosson's matrices, written as straight-line arithmetic.

function toOklab(r: number, g: number, b: number): [number, number, number];

Returns [number, number, number]

TypesCopy Anchor Link

HexCopy Anchor Link

type Hex = `#${string}`;

StyleCopy Anchor Link

type Style = Hex | readonly Format[];

ThemeCopy Anchor Link

A theme: a style per token, the ground the hex ones are checked against, and which WCAG level to hold them to.

type Theme = Partial<Record<TokenName, Style>> & {
    ground?: Hex;
    conformance?: Conformance;
};