import { ShapeGradient, VectorShape } from '../core/vector.js';
import { PdfRef } from './objects.js';
import { PdfDocument } from './writer.js';
interface Bbox {
    readonly minX: number;
    readonly minY: number;
    readonly maxX: number;
    readonly maxY: number;
}
/**
 * The local-space bounding box of a shape's paths (y-up).
 *
 * @returns The bounding box, or `undefined` for an empty/degenerate shape (where
 *   no gradient can be placed).
 */
export declare function shapeBbox(shape: VectorShape): Bbox | undefined;
/**
 * Build the PatternType-2 shading pattern object (axial or radial) for a
 * DrawingML gradient (EP16b) and add it to `doc`. The pattern's `/Matrix` is the
 * shape's CTM and the shading `/Coords` are in the shape's local space.
 *
 * @param gradient The gradient fill (kind, angle, colour stops).
 * @param bbox     The shape's local-space bounding box, from {@link shapeBbox}.
 * @param ctm      The shape's current transformation matrix, used as `/Matrix`.
 * @returns A reference to the `/Pattern` object, for a `/Pattern cs /Pn scn` fill.
 */
export declare function buildGradientPattern(doc: PdfDocument, gradient: ShapeGradient, bbox: Bbox, ctm: readonly [number, number, number, number, number, number]): PdfRef;
/**
 * §11.6.5.2 — the luminosity soft mask a gradient with per-stop TRANSPARENCY is
 * painted through.
 *
 * A PDF shading has one colour per point and no alpha, so a gradient that fades
 * out is drawn as the colour shading masked by a second shading of the same
 * geometry whose GREY is the transparency: white where the stop is opaque,
 * black where it is clear. 45541_Footer's master lays a white band down the
 * left of every slide that starts half transparent, and painted flat it covered
 * the artwork behind it.
 *
 * @param doc      The document to add the objects to.
 * @param gradient The gradient fill.
 * @param bbox     The shape's local-space bounding box.
 * @param ctm      The shape's CTM, as the form's `/Matrix`.
 * @returns The mask form XObject, or `undefined` when every stop is opaque or
 *          the sweep has no shading type that can carry a mask.
 */
export declare function buildGradientAlphaMask(doc: PdfDocument, gradient: ShapeGradient, bbox: Bbox, ctm: readonly [number, number, number, number, number, number]): PdfRef | undefined;
export {};