Getting Started

Minimal Setup

Installation:
```
composer require bacon/bacon-qr-code
```

Basic Usage (Imagick backend):

use BaconQrCode\Writer;
use BaconQrCode\Renderer\ImageRenderer;
use BaconQrCode\Renderer\Image\ImagickImageBackEnd;

$writer = new Writer(new ImageRenderer(400, new ImagickImageBackEnd()));
$writer->writeFile('Hello World!', 'qrcode.png');

GD Alternative (if Imagick unavailable):

use BaconQrCode\Renderer\GDLibRenderer;

$writer = new Writer(new GDLibRenderer(400));
$writer->writeFile('Hello World!', 'qrcode.png');

First Use Case

Generate a QR code for a product page URL and embed it in a Blade view:

// In a controller
public function showProduct($id) {
    $qr = new Writer(new ImageRenderer(300, new ImagickImageBackEnd()));
    $qr->writeFile(route('product.show', $id), storage_path('app/qr_'.$id.'.png'));
    return view('product.show', ['qr_path' => 'qr_'.$id.'.png']);
}

// In Blade
<img src="{{ asset('storage/qr_'.$product->id.'.png') }}" alt="QR Code">

Implementation Patterns

Core Workflows

Dynamic QR Generation

// Generate QR for user-specific data
$userData = ['id' => $user->id, 'email' => $user->email];
$qrData = json_encode($userData);
$writer->writeFile($qrData, "user_{$user->id}.png");

Custom Styling

use BaconQrCode\Renderer\RendererStyle\RendererStyle;
use BaconQrCode\Renderer\Color\Rgb;

$style = new RendererStyle(400);
$style->setForegroundColor(new Rgb(0, 102, 204)); // Blue
$style->setBackgroundColor(new Rgb(255, 255, 255)); // White
$style->setMargin(2);

$renderer = new ImageRenderer($style, new ImagickImageBackEnd());

SVG Output for Scalability

use BaconQrCode\Renderer\Image\SvgImageBackEnd;

$writer = new Writer(new ImageRenderer(500, new SvgImageBackEnd()));
$writer->writeFile('https://example.com', 'qr.svg');

Batch Processing

$urls = ['url1', 'url2', 'url3'];
foreach ($urls as $index => $url) {
    $writer->writeFile($url, "batch_{$index}.png");
}

Integration Tips

Service Provider Pattern

// app/Providers/QrCodeServiceProvider.php
public function register() {
    $this->app->singleton('qr.writer', function() {
        return new Writer(new ImageRenderer(
            new RendererStyle(400),
            new ImagickImageBackEnd()
        ));
    });
}

Middleware for QR Generation

// Generate QR for all authenticated users
public function handle($request, Closure $next) {
    if (auth()->check()) {
        $writer = app('qr.writer');
        $writer->writeFile(route('user.profile', auth()->id()),
            storage_path("app/qr_{auth()->id()}.png"));
    }
    return $next($request);
}

API Endpoint

Route::get('/qr/{data}', function($data) {
    $writer = new Writer(new GDLibRenderer(300));
    $path = temp_path('qr_'.md5($data).'.png');
    $writer->writeFile($data, $path);
    return response()->file($path)->deleteFileAfterSend(true);
});

Caching Strategy

public function getQrCode($data) {
    $cacheKey = 'qr_'.md5($data);
    return Cache::remember($cacheKey, now()->addHours(1), function() use ($data) {
        $writer = app('qr.writer');
        $path = storage_path("app/{$cacheKey}.png");
        $writer->writeFile($data, $path);
        return $path;
    });
}

Gotchas and Tips

Common Pitfalls

Imagick Artifacts
- Issue: White pixel artifacts with ImagickImageBackEnd (especially with margin=0).
- Solution: Use SvgImageBackEnd or GDLibRenderer for artifact-free output.
```
// Fallback to SVG if artifacts are critical
$backend = extension_loaded('imagick') ? new ImagickImageBackEnd() : new SvgImageBackEnd();
```
GD Limitations
- Issue: GDLibRenderer produces square QR codes and lacks gradients.
- Solution: Use only for simple cases or when Imagick/SVG isn't available.
Memory Limits
- Issue: Large QR codes (e.g., version 40+) may hit memory limits.
- Solution: Use SvgImageBackEnd for scalable vector output or optimize size:
```
$style = new RendererStyle(300); // Smaller size
```
Extension Dependencies
- Issue: Missing xmlwriter for SVG output or imagick for raster images.
- Solution: Check extensions early and provide fallbacks:
```
if (!extension_loaded('xmlwriter')) {
    throw new \RuntimeException('xmlwriter extension required for SVG output');
}
```

Debugging Tips

Validate QR Codes Use online validators (e.g., QR Code Generator) to verify output.

Log Errors Wrap generation in try-catch:

try {
    $writer->writeFile($data, $path);
} catch (\Exception $e) {
    Log::error("QR Generation failed: {$e->getMessage()}");
    throw $e;
}

Size Calculation Use BaconQrCode\Writer::getSize() to estimate dimensions before generation:
```
$size = $writer->getSize($data);
$style = new RendererStyle($size);
```

Performance Optimization

Reuse Writers Instantiate writers once (e.g., in a service container) rather than per-request.

Cache Renderers

$renderer = new ImageRenderer(
    new RendererStyle(400),
    new ImagickImageBackEnd()
);
Cache::remember('qr.renderer', now()->addDays(7), function() use ($renderer) {
    return $renderer;
});

Async Generation Use queues for non-critical QR codes:
```
Queue::push(new GenerateQrJob($data, $path));
```

Advanced Features

Custom Eyes

use BaconQrCode\Renderer\RendererStyle\Eye\SimpleCircleEye;

$style = new RendererStyle(400);
$style->setEye(new SimpleCircleEye());

Gradient Backgrounds

use BaconQrCode\Renderer\Color\Rgb;
use BaconQrCode\Renderer\RendererStyle\Gradient\LinearGradient;

$style = new RendererStyle(400);
$style->setBackgroundGradient(
    new LinearGradient(
        new Rgb(255, 0, 0),
        new Rgb(0, 0, 255)
    )
);

Transparent PNGs

$style = new RendererStyle(400);
$style->setBackgroundColor(new Rgb(0, 0, 0, 0)); // RGBA with alpha=0

Configuration Quirks

PHP Version
- Requires PHP 8.1+ (as of v3.0.0). Use GDLibRenderer for older versions.

Imagick Antialiasing Enable for smoother edges (v3.1.0+):

$backend = new ImagickImageBackEnd();
$backend->setAntialias(true);

UTF-8 Handling Ensure input strings are UTF-8 encoded:
```
$data = mb_convert_encoding($data, 'UTF-8');
```
Error Handling Check for BaconQrCode\Exception\WriterException when generation fails.

Bacon Qr Code Laravel Package