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https://github.com/uber-archive/image-diff
Create image differential between two images
https://github.com/uber-archive/image-diff
Last synced: about 2 months ago
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Create image differential between two images
- Host: GitHub
- URL: https://github.com/uber-archive/image-diff
- Owner: uber-archive
- License: mit
- Archived: true
- Created: 2013-11-16T01:25:13.000Z (almost 11 years ago)
- Default Branch: master
- Last Pushed: 2017-08-28T01:58:44.000Z (about 7 years ago)
- Last Synced: 2024-07-25T22:42:40.337Z (about 2 months ago)
- Language: JavaScript
- Size: 69.3 KB
- Stars: 2,458
- Watchers: 1,749
- Forks: 94
- Open Issues: 6
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE-MIT
Awesome Lists containing this project
README
# image-diff [](https://travis-ci.org/uber/image-diff)
# Project deprecated
We no longer have any active maintainers on this project and as a result have halted maintenance.
As a replacement, please see alternative projects like `looks-same` and `pixelmatch`:
https://github.com/gemini-testing/looks-same
https://github.com/mapbox/pixelmatch
--------------------
Create image differential between two images
This was created as part of a [visual regression][] project.
[visual regression]: http://www.youtube.com/watch?v=1wHr-O6gEfc
## Getting Started
### Requirements
`image-diff` depends on [ImageMagick][].
Please install this before continuing.
[ImageMagick]: http://www.imagemagick.org/
### Setup
Install the module with: `npm install image-diff`
```javascript
var imageDiff = require('image-diff');
imageDiff({
actualImage: 'checkerboard.png',
expectedImage: 'white.png',
diffImage: 'difference.png',
}, function (err, imagesAreSame) {
// error will be any errors that occurred
// imagesAreSame is a boolean whether the images were the same or not
// diffImage will have an image which highlights differences
});
```
## Documentation
`image-diff` exposes the function `imageDiff` as its export.
### `imageDiff(options, cb)`
Create an differential image between multiple images
- options `Object`
- options.actualImage `String` - Path to actual image file
- options.actualImage **must** exist
- options.expectedImage `String` - Path to expected image file
- If options.expectedImage does not exist, a transparent image with the same height/width will be created.
- options.diffImage `String` - Optional path to output differential image
- options.shadow `Boolean` - Optional flag to indicate if we should draw a shadow of the unchanged parts of the images
- For example, if an image is `+` and we diff with `-`, then the image will have `|` be red but also contain a faded `-`
- By default, this options is `false` meaning a shadow will not be drawn
- cb `Function` - Error-first function to handle diff result
- `cb` should have the signature `function (err, imagesAreSame)`
- err `Error|null` - If there was an error in diffing, this will be it
- imagesAreSame `Boolean` - Indicates that images are same or not
### `imageDiff.getFullResult(options, cb)`
Same as `imageDiff` but yields a fuller result
- options `Object` - See `imageDiff#options`
- cb `Function` - Error-first function to handle diff result
- `cb` should have the signature `function (err, result)`
- err `Error|null` - If there was an error in diffing, this will be it
- result `Object`
- total `Float` - Root mean square pixel difference across all pixels
- Value can range from 0 (no difference) to 655535 (every pixel is different)
- percentage `Float` - Normalized total difference
- Value can range from 0.00 (no difference) to 1.00 (every pixel is different)
- More info here: http://www.imagemagick.org/discourse-server/viewtopic.php?f=1&t=17284
**Example:**
```javascript
var imageDiff = require('image-diff');
imageDiff.getFullResult({
actualImage: 'checkerboard.png',
expectedImage: 'white.png',
diffImage: 'difference.png',
}, function (err, result) {
// result = {total: 46340.2, difference: 0.707107}
});
```
### `imageDiff.getRawResult(options, cb)`
Same as `imageDiff` but yields raw CLI result
- options `Object` - See `imageDiff#options`
- cb `Function` - Error-first function to handle diff result
- `cb` should have the signature `function (err, result)`
- err `Error|null` - If there was an error in diffing, this will be it
- result `String` - Result from ImageMagick's `compare` command
- Example output can be found here: http://www.imagemagick.org/discourse-server/viewtopic.php?f=1&t=17284
### CLI usage
We offer an `image-diff` executable to diff from the CLI. When images match, its exit code will be `0`. When they don't match, then it will be non-zero (e.g. `1`).
```
$ image-diff --help
Usage: image-diff [options] [diff-image]
Options:
-h, --help output usage information
-V, --version output the version number
--shadow Draw a shadow of unchanges parts on diff image
```
Example usage:
```bash
# Images don't match
image-diff checkerboard.png white.png diff.png
echo $?
# 1
# We can look at `diff.png` for the diff result
# Images do match
image-diff checkerboard.png white.png
echo $?
# 0
```
## Contributing
In lieu of a formal styleguide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality. Lint via [grunt](https://github.com/gruntjs/grunt) and test via `npm test`.
## Attribution
The font used for the example image is [Arial][] 30pt bold and [Courier New][] 38pt.
[Arial]: http://en.wikipedia.org/wiki/Arial
[Courier New]: http://en.wikipedia.org/wiki/Courier_%28typeface%29#Courier_New
## License
Copyright (c) 2013 Uber
Licensed under the MIT license.