import { PDFObject } from './pdf-object.ts';
import type { PDFWriter } from './pdf-writer.ts';
/**
 * Represents a reference to a PDF object, identified by its object
 * number and generation number. Use `PDFRef.of()` method to create
 * instances, which ensures reference equality for the same
 * object/generation number combination.
 */
export declare class PDFRef extends PDFObject {
    #private;
    /**
     * Creates or returns a cached PDFRef with the given object number and
     * optional generation number. This ensures that `PDFRef.of(1, 0) ===
     * PDFRef.of(1, 0)` is always true.
     */
    static of(objNumber: number, genNumber?: number): PDFRef;
    /** The object number of the PDF reference. */
    readonly obj: number;
    /** The generation number of the PDF reference. */
    readonly gen: number;
    private constructor();
    /**
     * Writes the PDF reference to the given PDFWriter.
     */
    write(writer: PDFWriter): void;
}