/**
 * Read-only resolution of SpreadsheetML `CT_Color` to `#RRGGBB`.
 *
 * Stored attributes (`auto`, `indexed`, `rgb`, `theme`, `tint`) are never
 * rewritten. `rgbColor` is a computed view and must not be serialized.
 *
 * Citations:
 * - ECMA-376-1 §18.3.1.15 `color` / `tint` (HLS, HLSMAX = 255)
 * - ECMA-376-1 §18.8.27 `indexedColors` (implied default palette)
 * - ECMA-376-1 §20.1.6.2 `clrScheme` (theme index order; `sysClr` / `srgbClr`)
 * - ECMA-376-1 §14.2.7 Theme Part (Strict relationship)
 * - ECMA-376-4 §12.2.7 Theme Part (Transitional relationship)
 */
/**
 * Theme scheme used to resolve `theme` indexes. Twelve `#RRGGBB` slots
 * (alpha omitted). Missing slots stay unresolved.
 */
export interface ThemeColorScheme {
    readonly colors: ReadonlyArray<string | undefined>;
}
/**
 * Workbook color context for resolution. Indexed overrides replace the
 * implied §18.8.27 palette from index 0 when a `colors` collection is present.
 */
export interface ColorResolutionContext {
    readonly theme: ThemeColorScheme;
    readonly indexedRgb?: ReadonlyArray<string | undefined>;
}
/** Stored SpreadsheetML color attributes (no computed view). */
export interface StoredColor {
    readonly auto?: boolean;
    readonly indexed?: number;
    readonly rgb?: string;
    readonly theme?: number;
    readonly tint?: number;
}
/**
 * Apply ECMA-376-1 §18.3.1.15 tint to an RGB triple.
 * `tint` 0 leaves the color unchanged. Out-of-range tint is clamped to [-1, 1].
 */
export declare function applySpreadsheetTint(r: number, g: number, b: number, tint: number): {
    r: number;
    g: number;
    b: number;
};
/**
 * §18.3.1.15 luminance step. Exported so tests can pin the spec examples
 * without OOXML.
 */
export declare function applyTintToLuminance(lum: number, tint: number): number;
/**
 * Resolve a stored color to `#RRGGBB`, or `undefined` when automatic,
 * system-indexed, or otherwise unresolvable. Does not invent a color for
 * `auto`.
 */
export declare function resolveColorToRgb(color: StoredColor | undefined, context: ColorResolutionContext): string | undefined;
/**
 * Parse a theme part for the first `clrScheme` twelve-color list.
 * `srgbClr@val` wins; otherwise `sysClr@lastClr`. Unreadable slots are
 * undefined (callers may fall back only when the whole part is absent).
 */
export declare function parseThemeColorScheme(themeXml: string): ThemeColorScheme;
/** Office default scheme used only when no theme part is present. */
export declare function defaultThemeColorScheme(): ThemeColorScheme;
/**
 * Parse `indexedColors` / `rgbColor@rgb` overrides (ECMA-376-1 §18.8.27).
 * Returns undefined when the collection is absent.
 */
export declare function parseIndexedColorOverrides(colorsCollectionXml: string | undefined): ReadonlyArray<string | undefined> | undefined;
/** `#RRGGBB` uppercase, no alpha. */
export declare function formatRgbHex(r: number, g: number, b: number): string;