/**
 * Pure, DOM-free per-channel ink-coverage math for the separations panel.
 *
 * Computes the page-average coverage of each ink (mean ink % over every
 * sampled pixel, `[0, 100]`) from an RGBA buffer — process inks via the
 * closed-form CMYK approximation, spots via the cosine-similarity estimate.
 * Extracted (like `rasterCoords.ts` / `cappedBacking.ts`) so it unit-tests
 * without pdf.js or a canvas, and so the in-browser separations service and
 * any other consumer share one definition of "coverage".
 *
 * The two per-pixel primitives are **injected** (`CoverageMath`) rather than
 * imported, so this file stays off `browser/index.ts`'s circular-import
 * surface (the TDZ hazard `constants.ts` exists to avoid) and the aggregation
 * logic is testable with trivial stubs.
 */
/** Minimal ink shape the coverage math needs (a subset of `DetectedInk`). */
export interface CoverageInk {
    name: string;
    type: "process" | "spot";
    altRgb: [number, number, number];
}
/** The per-pixel primitives, injected so this module imports nothing. */
export interface CoverageMath {
    rgbToCmyk(r: number, g: number, b: number): {
        c: number;
        m: number;
        y: number;
        k: number;
    };
    estimateInkCoverage(r: number, g: number, b: number, altR: number, altG: number, altB: number): number;
}
/**
 * Page-average coverage per channel from an RGBA buffer, keyed by `ink.name`.
 *
 * Process inks → mean of the closed-form CMYK plate value; spots → mean of the
 * cosine-similarity estimate. Both averaged over the sampled pixels and scaled
 * to `[0, 100]`. `step` strides the pixel grid (1 → every pixel) so a large
 * raster can be sub-sampled without changing the mean in expectation. Returns
 * `{}` for an empty ink list or a zero-area buffer.
 */
export declare function channelCoverageFromRaster(rgba: Uint8ClampedArray | ReadonlyArray<number>, width: number, height: number, inks: ReadonlyArray<CoverageInk>, math: CoverageMath, step?: number): Record<string, number>;
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