import type { DocumentInitParameters } from 'pdfjs-dist/types/src/display/api';
/**
 * Maximum allowed value for `viewportScale`. Values above this limit would produce canvases
 * so large (an A4 page at scale 100 already yields ~5×10⁹ pixels) that they risk OOM crashes
 * before the pixel-count guard in `processPdfPage` can fire.
 */
export declare const MAX_VIEWPORT_SCALE = 100;
/**
 * Maximum canvas area in pixels. At 4 bytes per pixel, 100 MP ≈ 400 MB of raw bitmap memory.
 * Any page whose rendered (floored) canvas area exceeds this limit is rejected before canvas
 * allocation. The guard floors the viewport dimensions first so it bounds the bitmap actually
 * allocated rather than the slightly larger fractional viewport area.
 */
export declare const MAX_CANVAS_PIXELS = 100000000;
/**
 * Default upper bound on input PDF size in bytes. 256 MiB is a generous ceiling for legitimate
 * PDFs while keeping a single conversion well below typical service container memory limits.
 * The path branch of `getPdfFileBuffer()` runs `stat()` before `readFile()` so this also blocks
 * unbounded reads from `/dev/zero`, FIFOs, sockets, and other non-regular files.
 * Callers can override with `PdfToPngOptions.maxInputBytes`.
 */
export declare const MAX_INPUT_BYTES: number;
/**
 * Upper bound on `concurrencyLimit` when `processPagesInParallel` is `true`. At this cap,
 * peak in-flight canvas memory ≈ `16 × MAX_CANVAS_PIXELS × 4 bytes` ≈ 6.4 GiB, which is a
 * defensible ceiling for typical Node.js service containers while still allowing realistic
 * parallelism. Higher values would let a single conversion exhaust container memory.
 */
export declare const MAX_CONCURRENCY_LIMIT = 16;
/**
 * Sliding-window size used for sequential (non-parallel) conversions. The window lets the
 * off-thread PNG encode and disk write of finished pages overlap the main-thread render of the
 * next page. Result order is preserved by the window helper; rendered pixels are unaffected.
 *
 * Sized 3 by paired A/B measurement: on text-heavy documents PNG encode costs ~2× render, and a
 * second in-flight encode recovers a small but consistent margin (TAMReview.pdf: −2…−5% median
 * end-to-end vs window 2 in interleaved trials, faster in 3 of 4 pairs; larger single-run
 * differences did not replicate under controlled re-measurement). Window 4 measured within
 * noise of 3. Peak cost: up to three live canvases.
 */
export declare const SEQUENTIAL_PIPELINE_WINDOW = 3;
/**
 * Default values applied to `PdfToPngOptions` fields that are not explicitly set by the caller.
 * These are also used as the source of truth for documented defaults in JSDoc comments on the type.
 */
export declare const PDF_TO_PNG_OPTIONS_DEFAULTS: {
    viewportScale: number;
    disableFontFace: boolean;
    useSystemFonts: boolean;
    enableXfa: boolean;
    /** Used as the output filename stem when the PDF is supplied as a buffer rather than a file path. */
    outputFileMask: string;
    pdfFilePassword: undefined;
    concurrencyLimit: number;
    maxInputBytes: number;
};
/**
 * Relative paths to the pdfjs-dist asset directories.
 * Stored as raw strings so they can be resolved against `process.cwd()` at call time
 * (inside `propsToPdfDocInitParams`) rather than at module-load time. This ensures
 * applications that call `process.chdir()` after importing the library still get
 * correct paths.
 */
export declare const CMAP_RELATIVE_URL = "./node_modules/pdfjs-dist/cmaps/";
export declare const STANDARD_FONTS_RELATIVE_URL = "./node_modules/pdfjs-dist/standard_fonts/";
/**
 * Default pdfjs `DocumentInitParameters` used when initialising a PDF document.
 * - `cMapUrl` / `cMapPacked`: point to the pre-packed character maps bundled with `pdfjs-dist`,
 *    required for rendering CJK and other non-Latin PDFs correctly.
 * - `standardFontDataUrl`: path to the standard Type 1 / TrueType fonts bundled with `pdfjs-dist`,
 *    used as fallbacks when a PDF does not embed its fonts.
 *
 * Note: these values are raw relative paths. They are resolved to absolute paths at call time
 * by `propsToPdfDocInitParams` via `normalizePath`.
 */
export declare const DOCUMENT_INIT_PARAMS_DEFAULTS: DocumentInitParameters;