https://github.com/giovannicalo/node-jpeg

Node JPEG
https://github.com/giovannicalo/node-jpeg

jpeg node rgba yuv

Last synced: about 1 month ago
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Node JPEG

• Host: GitHub
• URL: https://github.com/giovannicalo/node-jpeg
• Owner: giovannicalo
• License: mit
• Created: 2021-07-26T03:32:58.000Z (over 3 years ago)
• Default Branch: master
• Last Pushed: 2024-08-15T00:47:19.000Z (5 months ago)
• Last Synced: 2024-08-15T18:38:37.184Z (5 months ago)
• Topics: jpeg, node, rgba, yuv
• Language: C++
• Homepage:
• Size: 1.13 MB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: readme.md
  • License: license

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README

        
# Node JPEG

[![Build Status](https://github.com/giovannicalo/node-jpeg/actions/workflows/build.yml/badge.svg)](https://github.com/giovannicalo/node-jpeg/actions/workflows/build.yml)

[![Coverage Status](https://coveralls.io/repos/github/giovannicalo/node-jpeg/badge.svg)](https://coveralls.io/github/giovannicalo/node-jpeg)

## Prerequisites

* [CMake](https://cmake.org) >= 3.21.0

## Installation

```bash

npm install giovannicalo/node-jpeg

```

> Not yet published to NPM. This will install it from GitHub.

## Usage

### Decoding

```javascript

const { promises: { readFile, writeFile } } = require("fs");

const { Format, decode } = require("jpeg");

(async () => {

    const jpeg = await readFile("foo.jpg");

    const rgba = await decode(jpeg, Format.rgba);

    console.log(rgba);

    // {

    //   data: Uint8ClampedArray(8294400) [...],

    //   format: 0,

    //   height: 1080,

    //   width: 1920

    // }

    await writeFile("foo.rgba", rgba.data);

    const yuv = await decode(jpeg, Format.yuv);

    console.log(yuv);

    // {

    //   data: Uint8ClampedArray(3110400) [...],

    //   format: 1,

    //   height: 1080,

    //   width: 1920

    // }

    await writeFile("foo.yuv", yuv.data);

})();

```

### Encoding

```javascript

const { promises: { readFile, writeFile } } = require("fs");

const { Format, encode } = require("jpeg");

(async () => {

    const rgba = {

        data: await readFile("foo.rgba"),

        format: Format.rgba,

        height: 1080,

        width: 1920

    };

    const rgbaJpeg = await encode(rgba, 90);

    console.log(rgbaJpeg);

    // 

    await writeFile("foo.jpg", rgbaJpeg);

    const yuv = {

        data: await readFile("foo.yuv"),

        format: Format.yuv,

        height: 1080,

        width: 1920

    };

    const yuvJpeg = await encode(yuv, 90);

    console.log(yuvJpeg);

    // 

    await writeFile("bar.jpg", yuvJpeg);

})();

```

## API

### `Format.rgba = 0`

Standard RGBA format.

### `Format.yuv = 1`

YUV I420 format. Smaller and faster than RGBA, but less straightforward. When decoding, if the source JPEG has odd dimensions, they will be rounded up to the nearest even number. Currently, decoding only works if the JPEG already has YUV colorspace and 4:2:0 subsampling.

### `decode(data: Buffer, format: Format = Format.rgba): Promise`

Decodes the JPEG image stored in the `data` `Buffer` as `format`, which can be either `Format.rgba` or `Format.yuv`.

Returns a promise resolving to an object with `data`, `height`, `format` and `width` properties.

### `encode(image: Image, quality: number = 90): Promise`

Encodes a raw `image` as JPEG with the given `quality`. `image` must be an object with `data`, `height`, `format` and `width` properties.

Returns a promise resolving to a `Buffer`.