/**
 * PDF Image Extractor - Universal Browser-Compatible Implementation
 *
 * Optimized for universal browser compatibility:
 * - Uses Canvas API for image processing (no Node.js dependencies)
 * - Browser-native compression via canvas.toBlob()
 * - Direct PDF.js object processing for maximum compatibility
 * - Supports multiple image formats and color spaces
 * - Uses zlib compression in Node.js for efficient PNG creation
 */
import type { ExtractedImage } from '../types/image.types.js';
export declare class PdfImageExtractor {
    /**
     * Memory-safe pixel threshold for auto-scaling
     * Reduced from 8M to 2M pixels for better memory management on large PDFs
     */
    private static readonly MAX_SAFE_PIXELS;
    private static readonly MAX_DIMENSION;
    /**
     * Maximum images per page to prevent memory explosion
     */
    private static readonly MAX_IMAGES_PER_PAGE;
    /**
     * Browser-compatible image processing using Canvas API
     */
    private static imageToBlob;
    /**
     * Extract images from a PDF page using comprehensive detection methods
     * @param page The PDF page to extract images from
     * @returns Array of extracted images as base64 strings
     */
    extractImagesFromPage(page: any): Promise<ExtractedImage[]>;
    /**
     * Extract images by analyzing PDF operator list
     * This detects inline images and Do (XObject) operations
     */
    private extractFromOperatorList;
    /**
     * Convert Uint8Array to base64 string
     */
    private arrayToBase64;
    /**
     * Check if an object is an image based on PDF.js patterns
     */
    private static isImageObject;
    /**
     * Create ExtractedImage from PDF.js object using EXACT WORKING LOGIC
     * Based on successful test-exact-browser-implementation.js
     */
    private static createExtractedImageFromObject;
    /**
     * Create extracted image from object with position information from transform matrix
     */
    private static createExtractedImageFromObjectWithTransform;
    /**
     * Create RGB data from raw pixel data with proper format detection and auto-scaling
     * EXACT LOGIC from successful test implementation
     */
    private static createImageDataFromPixelData;
    /**
     * Process RGBA pixel data with NO CONVERSION - keep RGBA format
     * Based on working implementation
     */
    private static processRGBADataNoConversion;
    /**
     * Process RGB pixel data with memory-safe scaling support
     * Based on working implementation
     */
    private static processRGBDataWithScaling;
    /**
     * CRC32 calculation
     */
    private static calculateCRC32;
    /**
     * Convert Uint8Array to base64 (universal implementation)
     */
    private static uint8ArrayToBase64;
    /**
     * Remove duplicate images based on dimensions and content
     */
    private static removeDuplicateImages;
    /**
     * Create simple data URL using raw pixel data
     * Uses zlib compression in Node.js for smaller output and less memory
     */
    private static createSimpleDataUrl;
    /**
     * Create compressed PNG using zlib (Node.js only)
     * Much smaller output size and uses streaming for better memory management
     */
    private static createCompressedPNG;
    /**
     * Create minimal but valid uncompressed PNG (zero dependencies approach)
     * PNG format supports uncompressed data - perfect for universal compatibility
     */
    private static createMinimalValidPNG;
    /**
     * Create uncompressed deflate stream manually (zero dependencies)
     * This creates a valid deflate format without using compression libraries
     */
    private static createUncompressedDeflateStream;
    /**
     * Calculate Adler-32 checksum (required for deflate format)
     */
    private static calculateAdler32;
    /**
     * Create simple PNG chunk
     */
    private static createSimplePNGChunk;
}
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