image-in-browser/lib/formats/jpeg/jpeg-quantize.d.ts

Package for encoding / decoding images, transforming images, applying filters, drawing primitives on images on the client side (no need for server Node.js)

/** @format */
import { MemoryImage } from '../../image/image.js';
import { JpegData } from './jpeg-data.js';
/**
 * Abstract class for JPEG quantization and inverse DCT operations.
 */
export declare abstract class JpegQuantize {
    /**
     * Offset for DCT clipping.
     */
    private static readonly _dctClipOffset;
    /**
     * Length for DCT clipping.
     */
    private static readonly _dctClipLength;
    /**
     * DCT clipping array.
     */
    private static readonly _dctClip;
    /**
     * Creates the DCT clipping array.
     * @returns {Uint8Array} The DCT clipping array.
     */
    private static createDctClip;
    /**
     * Quantizes the coefficients and applies the Inverse Discrete Cosine Transform (IDCT).
     *
     * A port of poppler's IDCT method which in turn is taken from:
     * Christoph Loeffler, Adriaan Ligtenberg, George S. Moschytz,
     * "Practical Fast 1-D DCT Algorithms with 11 Multiplications",
     * IEEE Intl. Conf. on Acoustics, Speech & Signal Processing, 1989, 988-991.
     *
     * @param {Int16Array} quantizationTable - The quantization table.
     * @param {Int32Array} coefBlock - The coefficient block.
     * @param {Uint8Array} dataOut - The output data array.
     * @param {Int32Array} dataIn - The input data array.
     */
    static quantizeAndInverse(quantizationTable: Int16Array, coefBlock: Int32Array, dataOut: Uint8Array, dataIn: Int32Array): void;
    /**
     * Converts a JPEG data object to a MemoryImage object.
     *
     * @param {JpegData} jpeg - The JPEG data object.
     * @returns {MemoryImage} The resulting MemoryImage object.
     */
    static getImageFromJpeg(jpeg: JpegData): MemoryImage;
}