Laravel AI SDK 图像生成实战

摘要

Laravel AI SDK 提供了统一的图像生成 API，支持 DALL-E、Stable Diffusion 等多种图像生成模型。本文将深入讲解如何使用 Laravel AI SDK 进行图像生成，包括：

  • 图像生成 API 基础用法
  • 支持的图像生成模型
  • 图像尺寸与质量控制
  • 图像编辑与变体生成
  • 批量图像生成
  • 实战案例：构建 AI 图像生成器

本文适合希望在 Laravel 应用中集成图像生成功能的开发者。

1. 图像生成概述

1.1 支持的模型

模型提供商特点
DALL-E 3OpenAI高质量、创意性强
DALL-E 2OpenAI编辑功能、变体生成
Stable Diffusion多提供商开源、可定制
ImagenGoogle真实感强
Midjourney 风格兼容 API艺术风格

1.2 基本用法

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use Laravel\Ai\Image;

$image = Image::of('A serene mountain landscape at sunset')->generate();

$rawContent = (string) $image;

1.3 保存图像

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$image = Image::of('A cute cat wearing a hat')->generate();

Storage::put('generated/cat.png', $image->toBinary());

2. 图像生成配置

2.1 模型选择

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$image = Image::of('A futuristic city')
    ->usingModel('dall-e-3')
    ->generate();

2.2 尺寸设置

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$image = Image::of('A beautiful garden')
    ->size(1024, 1024) // 1024x1024
    ->generate();

// 预设尺寸
$image = Image::of('A portrait')
    ->size('portrait') // 1024x1792
    ->generate();

$image = Image::of('A landscape')
    ->size('landscape') // 1792x1024
    ->generate();

2.3 质量设置

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$image = Image::of('A detailed illustration')
    ->quality('hd') // 'standard' 或 'hd'
    ->generate();

2.4 风格设置

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$image = Image::of('A sunset over the ocean')
    ->style('vivid') // 'vivid' 或 'natural'
    ->generate();

3. 图像编辑

3.1 基于图像编辑

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$image = Image::edit($existingImage)
    ->prompt('Add a rainbow in the sky')
    ->generate();

3.2 蒙版编辑

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$image = Image::edit($existingImage)
    ->mask($maskImage) // 白色区域将被修改
    ->prompt('Replace with a sunset')
    ->generate();

3.3 局部重绘

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$image = Image::inpaint($originalImage)
    ->mask($maskImage)
    ->prompt('A beautiful flower')
    ->generate();

4. 图像变体

4.1 生成变体

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$variants = Image::of($originalImage)
    ->variations(4) // 生成 4 个变体
    ->generate();

foreach ($variants as $variant) {
    Storage::put('variants/' . uniqid() . '.png', $variant);
}

4.2 变体配置

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$variants = Image::of($originalImage)
    ->variations(3)
    ->size(512, 512)
    ->generate();

5. 批量生成

5.1 批量提示词

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$prompts = [
    'A cat wearing a hat',
    'A dog wearing glasses',
    'A bird wearing a bowtie',
];

$images = Image::batch($prompts)
    ->size(512, 512)
    ->generate();

foreach ($images as $index => $image) {
    Storage::put("batch/image_{$index}.png", $image);
}

5.2 队列处理

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use Laravel\Ai\Jobs\GenerateImage;

foreach ($prompts as $prompt) {
    GenerateImage::dispatch($prompt)
        ->onQueue('image-generation');
}

6. 高级功能

6.1 负面提示词

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$image = Image::of('A beautiful woman')
    ->negativePrompt('blurry, low quality, distorted')
    ->generate();

6.2 种子控制

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$image = Image::of('A random pattern')
    ->seed(12345) // 固定种子确保可重复
    ->generate();

6.3 步数控制

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$image = Image::of('A detailed painting')
    ->steps(50) // Stable Diffusion 步数
    ->generate();

6.4 CFG Scale

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$image = Image::of('A fantasy castle')
    ->cfgScale(7.5) // 提示词相关性
    ->generate();

7. 实战案例：AI 图像生成器

7.1 控制器

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<?php

namespace App\Http\Controllers;

use Laravel\Ai\Image;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Storage;

class ImageGeneratorController extends Controller
{
    public function generate(Request $request)
    {
        $validated = $request->validate([
            'prompt' => 'required|string|max:1000',
            'size' => 'nullable|in:256,512,1024,portrait,landscape',
            'quality' => 'nullable|in:standard,hd',
            'style' => 'nullable|in:vivid,natural',
        ]);
        
        $image = Image::of($validated['prompt'])
            ->size($validated['size'] ?? '1024')
            ->quality($validated['quality'] ?? 'standard')
            ->style($validated['style'] ?? 'vivid')
            ->generate();
        
        $filename = 'generated/' . uniqid() . '.png';
        Storage::put($filename, $image->toBinary());
        
        return response()->json([
            'url' => Storage::url($filename),
            'revised_prompt' => $image->revisedPrompt(),
        ]);
    }
    
    public function edit(Request $request)
    {
        $validated = $request->validate([
            'image' => 'required|image|max:4096',
            'prompt' => 'required|string|max:1000',
            'mask' => 'nullable|image|max:4096',
        ]);
        
        $imagePath = $request->file('image')->store('temp');
        $imageContent = Storage::get($imagePath);
        
        $edited = Image::edit($imageContent)
            ->prompt($validated['prompt'])
            ->when($request->hasFile('mask'), function ($image) use ($request) {
                $maskPath = $request->file('mask')->store('temp');
                return $image->mask(Storage::get($maskPath));
            })
            ->generate();
        
        $filename = 'edited/' . uniqid() . '.png';
        Storage::put($filename, $edited->toBinary());
        
        Storage::delete([$imagePath]);
        if ($request->hasFile('mask')) {
            Storage::delete([$maskPath ?? null]);
        }
        
        return response()->json([
            'url' => Storage::url($filename),
        ]);
    }
    
    public function variations(Request $request)
    {
        $validated = $request->validate([
            'image' => 'required|image|max:4096',
            'count' => 'nullable|integer|min:1|max:4',
        ]);
        
        $imagePath = $request->file('image')->store('temp');
        $imageContent = Storage::get($imagePath);
        
        $variants = Image::of($imageContent)
            ->variations($validated['count'] ?? 1)
            ->generate();
        
        $urls = [];
        foreach ($variants as $index => $variant) {
            $filename = 'variants/' . uniqid() . '.png';
            Storage::put($filename, $variant->toBinary());
            $urls[] = Storage::url($filename);
        }
        
        Storage::delete($imagePath);
        
        return response()->json(['urls' => $urls]);
    }
}

7.2 Livewire 组件

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<?php

namespace App\Http\Livewire;

use Livewire\Component;
use Livewire\WithFileUploads;
use Laravel\Ai\Image;
use Illuminate\Support\Facades\Storage;

class ImageGenerator extends Component
{
    use WithFileUploads;
    
    public string $prompt = '';
    public string $size = '1024';
    public string $quality = 'standard';
    public string $style = 'vivid';
    
    public $generatedImage = null;
    public bool $generating = false;
    
    public function generate()
    {
        $this->validate([
            'prompt' => 'required|min:10|max:1000',
        ]);
        
        $this->generating = true;
        
        try {
            $image = Image::of($this->prompt)
                ->size($this->size)
                ->quality($this->quality)
                ->style($this->style)
                ->generate();
            
            $filename = 'generated/' . uniqid() . '.png';
            Storage::put($filename, $image->toBinary());
            
            $this->generatedImage = Storage::url($filename);
        } finally {
            $this->generating = false;
        }
    }
    
    public function render()
    {
        return view('livewire.image-generator');
    }
}

7.3 视图模板

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<div class="image-generator">
    <div class="form-group">
        <label>Prompt</label>
        <textarea 
            wire:model="prompt" 
            class="form-control"
            rows="3"
            placeholder="Describe the image you want to generate..."
        ></textarea>
    </div>
    
    <div class="row">
        <div class="col-md-4">
            <label>Size</label>
            <select wire:model="size" class="form-control">
                <option value="256">256x256</option>
                <option value="512">512x512</option>
                <option value="1024" selected>1024x1024</option>
                <option value="portrait">Portrait (1024x1792)</option>
                <option value="landscape">Landscape (1792x1024)</option>
            </select>
        </div>
        
        <div class="col-md-4">
            <label>Quality</label>
            <select wire:model="quality" class="form-control">
                <option value="standard">Standard</option>
                <option value="hd">HD</option>
            </select>
        </div>
        
        <div class="col-md-4">
            <label>Style</label>
            <select wire:model="style" class="form-control">
                <option value="vivid">Vivid</option>
                <option value="natural">Natural</option>
            </select>
        </div>
    </div>
    
    <button 
        wire:click="generate" 
        wire:loading.attr="disabled"
        class="btn btn-primary mt-3"
    >
        <span wire:loading.remove>Generate Image</span>
        <span wire:loading>Generating...</span>
    </button>
    
    @if($generatedImage)
        <div class="mt-4">
            <img src="{{ $generatedImage }}" class="img-fluid rounded" alt="Generated image">
            <a href="{{ $generatedImage }}" download class="btn btn-success mt-2">
                Download
            </a>
        </div>
    @endif
</div>

8. 图像处理管道

8.1 处理流程

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class ImagePipeline
{
    public function process(string $prompt): array
    {
        $results = [];
        
        foreach (['dall-e-3', 'stable-diffusion'] as $model) {
            $image = Image::of($prompt)
                ->usingModel($model)
                ->generate();
            
            $filename = "pipeline/{$model}_" . uniqid() . '.png';
            Storage::put($filename, $image->toBinary());
            
            $results[$model] = Storage::url($filename);
        }
        
        return $results;
    }
}

8.2 后处理

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use Intervention\Image\Facades\Image as Intervention;

class ImagePostProcessor
{
    public function process($generatedImage): string
    {
        $img = Intervention::make($generatedImage);
        
        $img->resize(800, null, function ($constraint) {
            $constraint->aspectRatio();
        });
        
        $img->insert(
            public_path('watermark.png'),
            'bottom-right',
            10,
            10
        );
        
        return $img->encode('png');
    }
}

9. 成本控制

9.1 成本估算

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use Laravel\Ai\Cost;

$cost = Cost::forImageGeneration(
    size: '1024x1024',
    quality: 'hd',
    model: 'dall-e-3'
);

echo $cost->inDollars(); // 0.08

9.2 用户配额

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class ImageGenerationService
{
    public function canGenerate(User $user): bool
    {
        $dailyLimit = $user->subscription->daily_image_limit;
        $todayCount = $user->generatedImages()
            ->whereDate('created_at', today())
            ->count();
        
        return $todayCount < $dailyLimit;
    }
    
    public function generate(User $user, string $prompt): Image
    {
        if (!$this->canGenerate($user)) {
            throw new QuotaExceededException('Daily image limit reached');
        }
        
        $image = Image::of($prompt)->generate();
        
        $user->generatedImages()->create([
            'prompt' => $prompt,
            'path' => $this->store($image),
        ]);
        
        return $image;
    }
}

10. 最佳实践

10.1 提示词优化

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class PromptOptimizer
{
    public function enhance(string $prompt): string
    {
        $enhancements = [
            'highly detailed',
            'professional photography',
            '8k resolution',
            'dramatic lighting',
        ];
        
        return $prompt . ', ' . implode(', ', $enhancements);
    }
}

10.2 错误处理

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try {
    $image = Image::of($prompt)->generate();
} catch (ContentPolicyException $e) {
    return back()->with('error', 'Your prompt violates content policy');
} catch (RateLimitException $e) {
    return back()->with('error', 'Too many requests. Please try again later');
} catch (AiException $e) {
    return back()->with('error', 'Image generation failed');
}

10.3 缓存策略

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use Illuminate\Support\Facades\Cache;

function getCachedImage(string $prompt): string
{
    $key = 'image:' . md5($prompt);
    
    return Cache::remember($key, now()->addDays(7), function () use ($prompt) {
        $image = Image::of($prompt)->generate();
        $filename = 'cached/' . uniqid() . '.png';
        Storage::put($filename, $image->toBinary());
        return Storage::url($filename);
    });
}

11. 总结

Laravel AI SDK 的图像生成功能为 Laravel 应用提供了强大的 AI 绘画能力：

  1. 统一 API：支持多种图像生成模型
  2. 灵活配置：尺寸、质量、风格可定制
  3. 编辑能力：支持图像编辑和变体生成
  4. 批量处理：队列支持大规模生成
  5. 成本控制：内置成本估算和配额管理

通过本指南，您已经掌握了 Laravel AI SDK 图像生成的核心功能，可以开始构建自己的 AI 图像生成应用了。

参考资料