Identicon

Generate unique identicon avatars from any string.

Installation

composer require yzalis/identicon

Requirements

• PHP 8.1+
• GD extension (for PNG output) or Imagick extension (optional)

Quick Start

use Yzalis\Identicon\Identicon;

// Generate a data URI for an img tag
$dataUri = Identicon::generate('john@example.com');
echo '<img src="' . $dataUri . '" alt="Avatar" />';

// With custom size
$dataUri = Identicon::generate('john@example.com', 128);

Builder Pattern

For more control, use the fluent builder:

use Yzalis\Identicon\IdenticonBuilder;

$identicon = (new IdenticonBuilder())
    ->size(256)
    ->gridSize(7)
    ->margin(16)
    ->color('#3498db')
    ->backgroundColor('#ffffff')
    ->useSvg()
    ->build();

$svg = $identicon->getImageData('john@example.com');
$dataUri = $identicon->getImageDataUri('john@example.com');

Configuration Options

Size

// Square image
$builder->size(128);  // 128x128 pixels

// Rectangle (if needed)
$builder->dimensions(200, 100);

Grid Size

The grid determines the pattern complexity (default: 5x5).

$builder->gridSize(7);  // 7x7 grid

// Auto-calculate based on image size
$builder->size(1024)->autoGridSize();  // ~17x17 grid

Margins

// Uniform margin
$builder->margin(16);  // 16px all sides

// Percentage margin
$builder->marginPercent(10);  // 10% of image size

// Per-side margin
$builder->margin([10, 20, 10, 20]);  // top, right, bottom, left

Colors

// Hex colors
$builder->color('#3498db');
$builder->color('fff');  // Short format

// RGB array
$builder->color([52, 152, 219]);

// Background
$builder->backgroundColor('#ffffff');
$builder->backgroundColor(null);  // Transparent (default)

Renderers

$builder->useSvg();         // SVG (vector, no extension needed)
$builder->useGd();          // PNG via GD (default)
$builder->useImageMagick(); // PNG via ImageMagick

Hash Algorithms

$builder->useSha256();  // Default, better distribution
$builder->useMd5();     // For v2 compatibility

Pre-computed Hashes (GDPR Compliance)

If you already have pre-computed hashes (e.g., for GDPR compliance where emails are stored as hashes), you can generate identicons directly from those hashes without re-hashing:

// Database stores hashed emails for privacy (GDPR)
$storedHash = 'acbd18db4cc2f85cedef654fccc4a4d8';  // MD5 of user email

$identicon = (new IdenticonBuilder())
    ->skipHashing()  // Use input directly as hash
    ->useSvg()
    ->build();

$avatar = $identicon->getImageDataUri($storedHash);

This ensures consistency: generating an identicon from "john@example.com" with MD5 hashing produces the same result as generating from its pre-computed MD5 hash with skipHashing() enabled.

// These produce identical identicons:
$email = 'john@example.com';
$hash = md5($email);

// Method 1: Hash the email
$id1 = (new IdenticonBuilder())->useMd5()->build();
$avatar1 = $id1->getImageData($email);

// Method 2: Use pre-computed hash directly
$id2 = (new IdenticonBuilder())->skipHashing()->build();
$avatar2 = $id2->getImageData($hash);

// $avatar1 === $avatar2

Output Methods

$identicon = (new IdenticonBuilder())->build();

// Get binary image data
$data = $identicon->getImageData('email@example.com');

// Get base64 data URI (for img src)
$dataUri = $identicon->getImageDataUri('email@example.com');

// Get raw base64 string
$base64 = $identicon->getImageBase64('email@example.com');

// Output directly to browser
$identicon->displayImage('email@example.com');

// Save to file
$identicon->saveToFile('email@example.com', '/path/to/avatar.png');

// Get the generated color
$color = $identicon->getColor('email@example.com');
echo $color->toHex();  // #3498db

v2 Compatibility

If you're upgrading from v2 and need to keep the same identicons:

$identicon = (new IdenticonBuilder())
    ->useV2Compatibility()
    ->build();

This activates:

• MD5 hashing (instead of SHA-256)
• Legacy color extraction algorithm
• 5x5 grid

See UPGRADE-3.0.md for full migration guide.

Advanced Usage

Custom Algorithms

use Yzalis\Identicon\Algorithm\HashAlgorithmInterface;
use Yzalis\Identicon\Value\Hash;

class MyHashAlgorithm implements HashAlgorithmInterface
{
    public function hash(string $input): Hash
    {
        return new Hash(hash('sha512', $input));
    }

    public function getName(): string
    {
        return 'sha512';
    }
}

$identicon = (new IdenticonBuilder())
    ->hashAlgorithm(new MyHashAlgorithm())
    ->build();

Custom Renderers

use Yzalis\Identicon\Renderer\RendererInterface;

class WebPRenderer implements RendererInterface
{
    // Implement render(), getMimeType(), getFileExtension(), isAvailable()
}

$identicon = (new IdenticonBuilder())
    ->renderer(new WebPRenderer())
    ->build();

Testing

composer install
composer test

Static Analysis

composer analyze

Code Style

composer cs       # Check
composer cs:fix   # Fix

License

MIT License. See LICENSE for details.

Credits

• Benjamin Laugueux benjamin@laugueux.org
• All contributors

Inspired by GitHub's blog post about identicons.