import { Color } from "./Color";
/**
 * OKLCH color helpers.
 *
 * OKLCH describes a color by lightness, chroma and hue, derived from Björn
 * Ottosson's OKLab. Unlike in HSL, equal steps of lightness or hue look
 * equally different to the eye, which suits balanced palettes built from one
 * color.
 *
 * Ranges:
 * - `l` (lightness): 0 (black) .. 1 (white)
 * - `c` (chroma):    0 (gray) .. ~0.37 (most saturated sRGB)
 * - `h` (hue):       0 .. 360 degrees
 *
 * @see {@link https://bottosson.github.io/posts/oklab/} for the source math
 */
export interface IOKLCH {
    /** Lightness, from `0` (black) to `1` (white). */
    l: number;
    /** Chroma, from `0` (gray) to about `0.37` (most saturated). */
    c: number;
    /** Hue, from `0` to `360` degrees. */
    h: number;
}
/**
 * Converts a [[Color]] to its OKLCH components.
 *
 * @param   color  Source color
 * @return         `{ l, c, h }`
 */
export declare function colorToOKLCH(color: Color): IOKLCH;
/**
 * Converts OKLCH components to a [[Color]]. By default, a color outside the
 * sRGB range is brought into it by reducing its chroma, keeping lightness and
 * hue.
 *
 * @param   l      Lightness, 0 .. 1
 * @param   c      Chroma, 0 .. ~0.37
 * @param   h      Hue, 0 .. 360 degrees
 * @param   clamp  Reduce chroma to fit sRGB (default `true`)
 * @return         Color
 */
export declare function oklchToColor(l: number, c: number, h: number, clamp?: boolean): Color;
/**
 * WCAG contrast ratio of two colors, from `1` (none) to `21` (black on white).
 *
 * @ignore
 */
export declare function contrastRatio(a: Color, b: Color): number;
/**
 * Returns `color` with its lightness moved away from the background's, just
 * far enough for `ratio` contrast against it, keeping its hue. A color that
 * already has it is returned as is.
 *
 * @ignore
 */
export declare function withContrast(color: Color, background: Color, ratio?: number): Color;
/**
 * A mid shade of a color for large fills such as map land, about as light as
 * the land in the light and dark themes.
 *
 * @ignore
 */
export declare function fillShade(color: IOKLCH, dark: boolean): Color;
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