/**
 * Page-scoped relayout of composed pages (#857, DESIGN §6): the layout of
 * a composed page is kept by what it reads — the resolved template, the
 * page's Markdown and blocks, the styles and fonts, the locale (in the
 * configuration), the page's side and geometry, and what the pass knows
 * of those blocks (heading numbers, part and section, the pictures they
 * show) — so a build that meets the same page again (the next pass, the
 * next keystroke elsewhere in the chapter, the same chapter paginated in
 * the background) reuses it instead of setting it again. An edit inside a
 * page, or a change of a property it reads, sets that page alone.
 *
 * The kept layout is position-free: on reuse its source offsets, content
 * indices, container ids and page index are moved to where the page now
 * stands. A page whose layout reads what this key does not hold (a
 * footnote, a cross-reference, a citation, a contents or index listing, a
 * comic strip), that leaves notes for the pass (a drop cap's warning, a
 * joining script's tracking) or whose content goes on on pages it adds
 * (#859) is always laid out afresh.
 */
import type { ContentBlock, InlineSpan } from '../parse/types.js';
import type { VDTPage } from '../vdt.js';
import { type ComposedPageInput, type ComposedPageLayout } from '../pipeline/composedLayout.js';
/** What the memo reads of the pass that lays the page out. */
export interface ComposedMemoContext {
    /** The chapter's Markdown body, and the offset of the body in the file. */
    markdown: string;
    bodyOffset: number;
    /** A key of the pass's resolved configuration (styles, typography,
     *  locale, page): see {@link configKeyOf}. Read once a page is met. */
    configKey(): string;
    /** What else the pass knows of content blocks `from`…`to` that their
     *  layout reads, or undefined when the page must be laid out afresh. */
    contextKey(from: number, to: number): string | undefined;
    /** Whether laying out blocks `from`…`to` left notes for the pass. */
    sideEffectsIn(from: number, to: number): boolean;
}
/** Drop every kept page (tests; a host that wants a cold build). */
export declare function clearComposedPageMemo(): void;
/** Turn the memo off (every composed page laid out afresh) or on again. */
export declare function setComposedPageMemo(on: boolean): void;
/** Pages reused, laid out and kept, and laid out without keeping. */
export declare function composedPageMemoStats(): {
    hits: number;
    misses: number;
    skipped: number;
    size: number;
};
/** A 64-bit digest of `parts` (two 32-bit FNV-style lanes, mixed) and
 *  their total length: the memo's keys stay short whatever a page holds. */
export declare function digest(parts: readonly string[]): string;
/** A key of a resolved configuration (or any plain object the layout
 *  does not change, a resolved template), computed once per object. */
export declare function configKeyOf(resolved: object): string;
/** Spans the memo cannot key: what prints something set elsewhere. */
export declare function spansReadOutside(spans: readonly InlineSpan[] | undefined): boolean;
/** Whether content block `b` lays out from what it holds and the key's
 *  context alone. */
export declare function blockMemoisable(b: ContentBlock): boolean;
/**
 * {@link layoutComposedPage}, kept by what it reads: the same page met
 * again is taken from the memo and moved to where it now stands.
 */
export declare function layoutComposedPageMemo(input: ComposedPageInput, ctx: ComposedMemoContext): ComposedPageLayout;
/**
 * What a composed page paints, as a key (#857): its frames' layout key
 * with what is laid round them (running heads, decoration, page number,
 * paper, the floats and notes no frame holds). Two pages with the same
 * key paint the same pixels with the same paint options, so a host can
 * keep a page's bitmap across a relayout. Undefined for a page without a
 * layout key (not a composed page, or one laid out afresh every time).
 */
export declare function composedPagePaintKey(page: VDTPage): string | undefined;
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