/**
 * RenderContext — centralizes the object-numbering allocator and the
 * resource-registry maps used during PDF serialization.
 *
 * Background. Historically, `renderPdfPages` kept all of this state as
 * ad-hoc local variables and Maps inside one 1,000+ line function. That
 * made ordering invariants (object 1 = catalog, fonts before page, etc.)
 * implicit and made the file difficult to split into phase-specific
 * subsystems. `RenderContext` gathers the state into a single object so
 * the eventual refactor of `renderPdfPages` and the Phase 6 widget
 * extraction can share a uniform handle.
 *
 * This module has no callers yet — see M2.b in
 * docs/audit-0422/4-pdf-refactor-plan.md for the integration plan.
 *
 * Contract notes:
 *  - `allocateRef()` returns monotonically increasing object numbers
 *    starting at 1. Generation numbers are always 0 for newly-written
 *    documents (PDF spec allows >0 only for incremental updates).
 *  - `addObject(ref, value)` preserves insertion order. The writer
 *    sorts by object number before emitting, so insertion order is
 *    not load-bearing for output — but it is load-bearing for our
 *    tests that snapshot the object stream.
 *  - Resource registries are opt-in: the renderer may allocate a ref
 *    via `allocateRef()` without also registering the resource if the
 *    object isn't in a lookup-by-key path.
 */
import type { PDFDictionary, PDFStream } from "./pdf-objects.js";
import { PDFRef } from "./pdf-objects.js";
export interface RenderContextObject {
    ref: PDFRef;
    value: PDFDictionary | PDFStream;
}
export interface RenderContextSnapshot {
    /** All registered objects in insertion order. */
    readonly objects: ReadonlyArray<RenderContextObject>;
    /** The next unallocated object number (= last allocated + 1). */
    readonly nextObjectNumber: number;
}
export declare class RenderContext {
    private nextObjectNumber;
    private readonly objects;
    private readonly fontRefs;
    private readonly imageRefs;
    private readonly imageAliases;
    private readonly formRefs;
    private readonly formAliases;
    private readonly extRefs;
    private readonly extAliases;
    private readonly shadingRefs;
    private readonly shadingAliases;
    allocateRef(): PDFRef;
    /**
     * Allocate a contiguous run of object refs in a single call.
     *
     * Used for compound objects that need adjacent numbering (e.g. an
     * embedded font emits 6 related objects — Type0, CIDFont, descriptor,
     * font-file stream, CIDToGIDMap stream, ToUnicode CMap — and the
     * renderer wires them up by offset).
     */
    allocateRefBlock(count: number): PDFRef[];
    addObject(ref: PDFRef, value: PDFDictionary | PDFStream): void;
    registerFont(key: string, ref: PDFRef): void;
    getFontRef(key: string): PDFRef | undefined;
    registerImage(key: string, ref: PDFRef, alias: string): void;
    getImageRef(key: string): PDFRef | undefined;
    getImageAlias(key: string): string | undefined;
    registerForm(key: string, ref: PDFRef, alias: string): void;
    getFormRef(key: string): PDFRef | undefined;
    getFormAlias(key: string): string | undefined;
    registerExtGState(key: string, ref: PDFRef, alias: string): void;
    getExtGStateRef(key: string): PDFRef | undefined;
    getExtGStateAlias(key: string): string | undefined;
    registerShading(key: string, ref: PDFRef, alias: string): void;
    getShadingRef(key: string): PDFRef | undefined;
    getShadingAlias(key: string): string | undefined;
    /**
     * Returns a frozen, read-only view of the current state. Intended for
     * handoff to the writer at end-of-render; further mutations to the
     * context are still possible but won't be reflected in this snapshot.
     */
    snapshot(): RenderContextSnapshot;
    /** Iterate registered objects without allocating a snapshot array. */
    iterateObjects(): IterableIterator<RenderContextObject>;
    /** Iterate font (key, ref) pairs in registration order. */
    iterateFonts(): IterableIterator<[string, PDFRef]>;
    /** Iterate image (key, ref, alias) triples in registration order. */
    iterateImages(): IterableIterator<[string, PDFRef, string]>;
    /** Iterate form (key, ref, alias) triples in registration order. */
    iterateForms(): IterableIterator<[string, PDFRef, string]>;
    /** Iterate ExtGState (key, ref, alias) triples in registration order. */
    iterateExtGStates(): IterableIterator<[string, PDFRef, string]>;
    /** Iterate shading (key, ref, alias) triples in registration order. */
    iterateShadings(): IterableIterator<[string, PDFRef, string]>;
    get objectCount(): number;
}