/** Split a `#rrggbb` hex color into its `[r, g, b]` channels (0–255).
 * @internal
 */
export declare function hexToRgb(hex: string): readonly [number, number, number];
/** Combine `[r, g, b]` channels (0–255, rounded) into a `#rrggbb` hex string.
 * @internal
 */
export declare function rgbToHex(r: number, g: number, b: number): string;
/** Interpolate between two `#rrggbb` colors by fraction `t`, clamped to the endpoints.
 * @internal
 */
export declare function mixHex(from: string, to: string, t: number): string;