/**
 * @license
 * Copyright 2019 Google Inc. All Rights Reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * =============================================================================
 */
import { Tensor3D, Tensor4D } from '@tensorflow/tfjs-core';
export declare enum ImageType {
    JPEG = "jpeg",
    PNG = "png",
    GIF = "gif",
    BMP = "BMP"
}
/**
 * Decode a JPEG-encoded image to a 3D Tensor of dtype `int32`.
 *
 * @param contents The JPEG-encoded image in an Uint8Array.
 * @param channels An optional int. Defaults to 0. Accepted values are
 *     0: use the number of channels in the PNG-encoded image.
 *     1: output a grayscale image.
 *     3: output an RGB image.
 * @param ratio An optional int. Defaults to 1. Downscaling ratio. It is used
 *     when image is type Jpeg.
 * @param fancyUpscaling An optional bool. Defaults to True. If true use a
 *     slower but nicer upscaling of the chroma planes. It is used when image is
 *     type Jpeg.
 * @param tryRecoverTruncated An optional bool. Defaults to False. If true try
 *     to recover an image from truncated input. It is used when image is type
 *     Jpeg.
 * @param acceptableFraction An optional float. Defaults to 1. The minimum
 *     required fraction of lines before a truncated input is accepted. It is
 *     used when image is type Jpeg.
 * @param dctMethod An optional string. Defaults to "". string specifying a hint
 *     about the algorithm used for decompression. Defaults to "" which maps to
 *     a system-specific default. Currently valid values are ["INTEGER_FAST",
 *     "INTEGER_ACCURATE"]. The hint may be ignored (e.g., the internal jpeg
 *     library changes to a version that does not have that specific option.) It
 *     is used when image is type Jpeg.
 * @returns A 3D Tensor of dtype `int32` with shape [height, width, 1/3].
 */
/**
 * @doc {heading: 'Operations', subheading: 'Images', namespace: 'node'}
 */
export declare function decodeJpeg(contents: Uint8Array, channels?: number, ratio?: number, fancyUpscaling?: boolean, tryRecoverTruncated?: boolean, acceptableFraction?: number, dctMethod?: string): Tensor3D;
/**
 * Decode a PNG-encoded image to a 3D Tensor of dtype `int32`.
 *
 * @param contents The BMP-encoded image in an Uint8Array.
 * @param channels An optional int. Defaults to 0. Accepted values are
 *      0: use the number of channels in the PNG-encoded image.
 *      1: output a grayscale image.
 *      3: output an RGB image.
 *      4: output an RGBA image.
 * @param dtype The data type of the result. Only `int32` is supported at this
 *     time.
 * @returns A 3D Tensor of dtype `int32` with shape [height, width, 1/3/4].
 */
/**
 * @doc {heading: 'Operations', subheading: 'Images', namespace: 'node'}
 */
export declare function decodePng(contents: Uint8Array, channels?: number, dtype?: string): Tensor3D;
/**
 * Decode the first frame of a BMP-encoded image to a 3D Tensor of dtype
 * `int32`.
 *
 * @param contents The BMP-encoded image in an Uint8Array.
 * @param channels An optional int. Defaults to 0. Accepted values are
 *      0: use the number of channels in the BMP-encoded image.
 *      3: output an RGB image.
 *      4: output an RGBA image.
 * @returns A 3D Tensor of dtype `int32` with shape [height, width, 3/4].
 */
/**
 * @doc {heading: 'Operations', subheading: 'Images', namespace: 'node'}
 */
export declare function decodeBmp(contents: Uint8Array, channels?: number): Tensor3D;
/**
 * Decode the frame(s) of a GIF-encoded image to a 4D Tensor of dtype `int32`.
 *
 * @param contents The GIF-encoded image in an Uint8Array.
 * @returns A 4D Tensor of dtype `int32` with shape [num_frames, height, width,
 *     3]. RGB channel order.
 */
/**
 * @doc {heading: 'Operations', subheading: 'Images', namespace: 'node'}
 */
export declare function decodeGif(contents: Uint8Array): Tensor4D;
/**
 * Given the encoded bytes of an image, it returns a 3D or 4D tensor of the
 * decoded image. Supports BMP, GIF, JPEG and PNG formats.
 *
 * @param content The encoded image in an Uint8Array.
 * @param channels An optional int. Defaults to 0, use the number of channels in
 *     the image. Number of color channels for the decoded image. It is used
 *     when image is type Png, Bmp, or Jpeg.
 * @param dtype The data type of the result. Only `int32` is supported at this
 *     time.
 * @param expandAnimations A boolean which controls the shape of the returned
 *     op's output. If True, the returned op will produce a 3-D tensor for PNG,
 *     JPEG, and BMP files; and a 4-D tensor for all GIFs, whether animated or
 *     not. If, False, the returned op will produce a 3-D tensor for all file
 *     types and will truncate animated GIFs to the first frame.
 * @returns A Tensor with dtype `int32` and a 3- or 4-dimensional shape,
 *     depending on the file type. For gif file the returned Tensor shape is
 *     [num_frames, height, width, 3], and for jpeg/png/bmp the returned Tensor
 *     shape is []height, width, channels]
 */
/**
 * @doc {heading: 'Operations', subheading: 'Images', namespace: 'node'}
 */
export declare function decodeImage(content: Uint8Array, channels?: number, dtype?: string, expandAnimations?: boolean): Tensor3D | Tensor4D;
/**
 * Encodes an image tensor to JPEG.
 *
 * @param image A 3-D uint8 Tensor of shape [height, width, channels].
 * @param format An optional string from: "", "grayscale", "rgb".
 *     Defaults to "". Per pixel image format.
 *     - '': Use a default format based on the number of channels in the image.
 *     - grayscale: Output a grayscale JPEG image. The channels dimension of
 *       image must be 1.
 *     - rgb: Output an RGB JPEG image. The channels dimension of image must
 *       be 3.
 * @param quality An optional int. Defaults to 95. Quality of the compression
 *     from 0 to 100 (higher is better and slower).
 * @param progressive An optional bool. Defaults to False. If True, create a
 *     JPEG that loads progressively (coarse to fine).
 * @param optimizeSize An optional bool. Defaults to False. If True, spend
 *     CPU/RAM to reduce size with no quality change.
 * @param chromaDownsampling  An optional bool. Defaults to True.
 *     See http://en.wikipedia.org/wiki/Chroma_subsampling.
 * @param densityUnit An optional string from: "in", "cm". Defaults to "in".
 *     Unit used to specify x_density and y_density: pixels per inch ('in') or
 *     centimeter ('cm').
 * @param xDensity An optional int. Defaults to 300. Horizontal pixels per
 *     density unit.
 * @param yDensity An optional int. Defaults to 300. Vertical pixels per
 *     density unit.
 * @param xmpMetadata An optional string. Defaults to "". If not empty, embed
 *     this XMP metadata in the image header.
 * @returns The JPEG encoded data as an Uint8Array.
 */
/**
 * @doc {heading: 'Operations', subheading: 'Images', namespace: 'node'}
 */
export declare function encodeJpeg(image: Tensor3D, format?: '' | 'grayscale' | 'rgb', quality?: number, progressive?: boolean, optimizeSize?: boolean, chromaDownsampling?: boolean, densityUnit?: 'in' | 'cm', xDensity?: number, yDensity?: number, xmpMetadata?: string): Promise<Uint8Array>;
/**
 * Encodes an image tensor to PNG.
 *
 * @param image A 3-D uint8 Tensor of shape [height, width, channels].
 * @param compression An optional int. Defaults to -1. Compression level.
 * @returns The PNG encoded data as an Uint8Array.
 */
/**
 * @doc {heading: 'Operations', subheading: 'Images', namespace: 'node'}
 */
export declare function encodePng(image: Tensor3D, compression?: number): Promise<Uint8Array>;
/**
 * Helper function to get image type based on starting bytes of the image file.
 */
export declare function getImageType(content: Uint8Array): string;