/** sRGB colour: `r`/`g`/`b` in `0–255`, `a` in `0–1`. */
export interface RgbColor {
    r: number;
    g: number;
    b: number;
    a: number;
}
/** HSL colour: `h` in `0–360` degrees, `s`/`l` in `0–100` percent, `a` in `0–1`. */
export interface HslColor {
    h: number;
    s: number;
    l: number;
    a: number;
}
/** HSB (a.k.a. HSV) colour: `h` in `0–360` degrees, `s`/`b` in `0–100` percent, `a` in `0–1`; `b` is brightness, not blue. */
export interface HsbColor {
    h: number;
    s: number;
    b: number;
    a: number;
}
/** Serialisation targets for {@link formatColor}; `'hsb'` is this library's own notation, not CSS, so it round-trips through {@link parseColor} but must not go in a stylesheet. */
export type ColorFormat = 'hex' | 'rgb' | 'hsl' | 'hsb';
/**
 * Serialises an sRGB colour as `#rrggbb`, or `#rrggbbaa` when `includeAlpha` is set, clamping and rounding channels so a computed colour with `r: 255.4` still produces valid hex.
 *
 * @example
 * ```ts
 * rgbToHex({ r: 217, g: 76, b: 76, a: 0.5 });       // '#d94c4c'
 * rgbToHex({ r: 217, g: 76, b: 76, a: 0.5 }, true); // '#d94c4c80'
 * ```
 */
export declare function rgbToHex(rgb: RgbColor, includeAlpha?: boolean): string;
/**
 * Parses `#rgb`, `#rgba`, `#rrggbb` or `#rrggbbaa` into sRGB, returning `null` for anything else, including 5- and 7-digit strings that look like hex but aren't a colour.
 *
 * @example
 * ```ts
 * hexToRgb('#f00');       // { r: 255, g: 0, b: 0, a: 1 }
 * hexToRgb('#ff000080');  // { r: 255, g: 0, b: 0, a: 0.502 }
 * hexToRgb('nope');       // null
 * ```
 */
export declare function hexToRgb(hex: string): RgbColor | null;
/** sRGB → HSB. A greyscale colour reports hue `0`, because it genuinely has none. */
export declare function rgbToHsb(rgb: RgbColor): HsbColor;
/** HSB → sRGB. */
export declare function hsbToRgb(hsb: HsbColor): RgbColor;
/** sRGB → HSL. */
export declare function rgbToHsl(rgb: RgbColor): HslColor;
/** HSL → sRGB. */
export declare function hslToRgb(hsl: HslColor): RgbColor;
/** HSB → HSL, computed directly rather than via RGB, since the detour would quantise to 8 bits and flatten near-black hues. */
export declare function hsbToHsl(hsb: HsbColor): HslColor;
/** HSL → HSB, the exact inverse of {@link hsbToHsl}, also without an RGB detour. */
export declare function hslToHsb(hsl: HslColor): HsbColor;
/**
 * Parses a colour string (hex, `rgb()`, `hsl()`, or this library's own `hsb()`) into the canonical {@link HsbColor}, returning `null` rather than throwing for anything unrecognized, including named colours.
 *
 * @example
 * ```ts
 * parseColor('#d94c4c');                 // { h: 0, s: 64.98, b: 85.1, a: 1 }
 * parseColor('rgb(255 0 0 / 50%)');      // { h: 0, s: 100, b: 100, a: 0.5 }
 * parseColor('hsl(210, 60%, 85%)');      // { h: 210, s: 19.15, b: 94, a: 1 }
 * parseColor('rebeccapurple');           // null
 * ```
 */
export declare function parseColor(input: string): HsbColor | null;
/**
 * Serialises the canonical {@link HsbColor} back to a string in `format`, omitting alpha only when it equals 1 unless `alpha: false` forces it off; round-trips through {@link parseColor} to the precision `format` can carry.
 *
 * @example
 * ```ts
 * formatColor({ h: 0, s: 100, b: 100, a: 1 }, 'hex');          // '#ff0000'
 * formatColor({ h: 0, s: 100, b: 100, a: 0.5 }, 'hex');        // '#ff000080'
 * formatColor({ h: 0, s: 100, b: 100, a: 0.5 }, 'rgb');        // 'rgba(255, 0, 0, 0.5)'
 * formatColor({ h: 0, s: 100, b: 100, a: 0.5 }, 'hex', false); // '#ff0000'
 * ```
 */
export declare function formatColor(color: HsbColor, format: ColorFormat, alpha?: boolean): string;