# img-diff-js

**Repository Path**: mirrors_bokuweb/img-diff-js

## Basic Information

- **Project Name**: img-diff-js
- **Description**: :art: Node.js library to compare 2 images without native libs.
- **Primary Language**: Unknown
- **License**: MIT
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2020-08-08
- **Last Updated**: 2026-02-07

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# img-diff-js

[![CircleCI](https://circleci.com/gh/reg-viz/img-diff-js.svg?style=svg)](https://circleci.com/gh/reg-viz/img-diff-js)
[![Build Status](https://travis-ci.org/reg-viz/img-diff-js.svg?branch=master)](https://travis-ci.org/reg-viz/img-diff-js)
[![npm version](https://badge.fury.io/js/img-diff-js.svg)](https://badge.fury.io/js/img-diff-js)
[![License: MIT](https://img.shields.io/badge/License-MIT-blue.svg)](https://opensource.org/licenses/MIT)


:art: Node.js library to compare 2 images without native libs.

| Actual | Expected | Difference |
|:---:|:---:|:---:|
| ![actual](example/actual.png) | ![expected](example/expected.png) | ![diff](example/diff.png) |

## Install

```sh
npm install img-diff-js
```

```js
const { imgDiff } = require('img-diff-js');

imgDiff({
  actualFilename: 'example/actual.png',
  expectedFilename: 'example/expected.png',
  diffFilename: 'example/diff.png',
}).then(result => console.log(result));
```

## API Usage

### `imgDiff(opt: ImgDiffOptions): Promise<ImgDiffRestul>`
Create image differential between two images

#### `ImgDiffOptions`

```ts
{
  actualFilename: string;
  expectedFilename: string;
  diffFilename?: string;
  options?: {
    threshold?: number;   // default 0.1
    includeAA?: boolean;  // default false
  }
}
```

- `actualFilename` - *Required* - Path to actual image file.
- `expectedFilename` - *Required* - Path to expected image file.
- `diffFilename` - *Optional* - Path to differential image file. If omitted it, `imgDiff` does does not output image file.
- `options` - *Optional* - An object to pass through [pixelmatch](https://github.com/mapbox/pixelmatch#api).

#### `ImgDiffResult`

```ts
{
  width: number;
  height: number;
  imagesAreSame: boolean;
}
```

- `width` - Differential image's width.
- `height` - Differential image's height.
- `imagesAreSame` - It'll be true only if 2 images are same perfectly.

## Available format

The following codecs are available for input image files.

- [x] png
- [x] jpeg
- [x] tiff (limited. See https://github.com/Quramy/decode-tiff#compatibility )
- [ ] bmp

`imgDiff` detects the input image format from it's extension name. For example, if the input file name ends with ".jpeg", `imgDiff` attempts to decode in JPEG way regardless of the actual file format.

## Performance

 | case name | img-diff-js | image-difference | image-diff | 
 |:---|---:|---:|---:|
 | 50 same dimension PNGs | 936 msec | 11018 msec | 16539 msec | 
 | 50 different dimension PNGs | 715 msec | 16077 msec | 16639 msec | 
 | 50 same dimension JPEGs | 1076 msec | 10910 msec | 19078 msec | 

The above table was captured under [Travis-CI](https://travis-ci.org/reg-viz/img-diff-js). If you want the latest result, check the raw log.

## Contribute
PR or issue is welcome :)

### Setup

```sh
yarn
```

### Test

```sh
yarn test
```

### Run benchmark script

```sh
yarn run perf
```

## License

MIT License. See LICENSE under this repository.