Compare images using PHP

This package can compare two images and return the percentage of matching pixels. It's a PHP wrapper around the Pixelmatch JavaScript library.

Here's a quick example on how to use the package.

use Spatie\Pixelmatch\Pixelmatch;

$pixelmatch = Pixelmatch::new("path/to/file1.png", "path/to/file2.png");

$pixelmatch->matchedPixelPercentage(); // returns a float, for example 97.5
$pixelmatch->mismatchedPixelPercentage(); // returns a float, for example 2.5

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Installation

You can install the package via composer:

composer require spatie/pixelmatch-php

In your project, or on your server, you must have the JavaScript package Pixelmatch installed.

npm install pixelmatch

... or Yarn.

yarn add pixelmatch

Make sure you have installed Node 16 or higher.

Usage

Here's how you can get the percentage of matching pixels between two images.

use Spatie\Pixelmatch\Pixelmatch;

$pixelmatch = Pixelmatch::new("path/to/file1.png", "path/to/file2.png");

$pixelmatch->matchedPixelPercentage(); // returns a float, for example 97.5
$pixelmatch->mismatchedPixelPercentage(); // returns a float, for example 2.5

To get the amount of matched and mismatched pixels, you can use these methods.

use Spatie\Pixelmatch\Pixelmatch;

$pixelmatch = Pixelmatch::new("path/to/file1.png", "path/to/file2.png");

$pixelmatch->matchedPixels(); // returns an int
$pixelmatch->mismatchedPixels(); // returns an int

You can use the matches function to check if the images match.

use Spatie\Pixelmatch\Pixelmatch;

$pixelmatch = Pixelmatch::new("path/to/file1.png", "path/to/file2.png");
$pixelmatch->matches(); // returns a boolean
$pixelmatch->doesNotMatch(); // returns a boolean

Setting a threshold

To set the threshold for the amount of mismatching pixels, you can use the threshold method. Higher values will make the comparison more sensitive. The threshold should be between 0 and 1.

If you don't set a threshold, we'll use the default value of 0.1.

$pixelmatch->threshold(0.05);

Ignoring anti-aliasing

To ignore anti-aliased pixels, you can use the includeAa method.

$pixelmatch->includeAa();

Limitations

The package can only compare png images.

Images with different dimensions cannot be compared. If you try to do this, a Spatie\Pixelmatch\Exceptions\CouldNotCompare exception will be thrown.

Testing

composer test

Changelog

Please see CHANGELOG for more information on what has changed recently.

Contributing

Please see CONTRIBUTING for details.

Security Vulnerabilities

Please review our security policy on how to report security vulnerabilities.

Credits

• Niels Vanpachtenbeke
• Freek Van der Herten
• All Contributors

License

The MIT License (MIT). Please see License File for more information.