Panelize Backend

The backend for Panelize, an AI-powered comic book and manga panel generator. This Flask-based server takes in user-written stories and returns a sequence of AI-generated images with captions — powered by GPT-4o, DALL·E 3, and BLIP.

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Technologies Used

• Python 3.10+
• Flask — lightweight REST API framework
• OpenAI API (GPT-4o & DALL·E 3) — for prompt engineering and image generation
• Hugging Face Transformers — for BLIP image captioning
• Pillow (PIL) — for image processing
• CORS — to allow frontend interaction
• Requests — for image retrieval from OpenAI URLs

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Features

• Story decomposition into sequential panel prompts using GPT-4o
• Image generation with DALL·E 3 in chosen art styles (manga, comic book, custom)
• Image captioning with BLIP to inform chained prompts
• Prompt chaining logic to maintain visual-narrative flow across panels
• REST API returns panel prompts, images, and captions as JSON
• API key handling via environment variables

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Local Setup

1. Clone the Repo

git clone https://github.com/yourusername/panelize_backend.git
cd panelize_backend

2. Create and Activate a Virtual Environment

python -m venv .venv
source .venv/bin/activate        # On Windows: .\.venv\Scripts\activate

3. Install Dependencies

pip install -r requirements.txt

4. Set Your OpenAI API Key

# Linux/macOS
export OPENAI_API_KEY=your-key-here

# Windows PowerShell
$env:OPENAI_API_KEY="your-key-here"

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Running the Server

Local Development

flask run

Server will be live at: http://127.0.0.1:5000

Production/Render Deployment

gunicorn app:app --bind 0.0.0.0:5000

This is the recommended command for deploying on Render or any production server.

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API Usage

POST /api/generate-panels

Request:

{
  "story_description": "A samurai travels through time and meets a future AI...",
  "num_panels": 3,
  "style": "manga"
}

Response:

{
  "panels": [
    {
      "prompt": "In colored manga theme generate the following: ...",
      "image_url": "https://...",
      "caption": "A lone samurai stands in a neon-lit alley..."
    },
    ...
  ]
}

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Project Structure

panelize_backend/
├── app.py                    # Main Flask app entry
├── routes/
│   └── panel_routes.py       # API routes
├── services/
│   └── openai_service.py     # GPT/DALL·E/BLIP logic
├── requirements.txt
└── .env                      # Optional OpenAI API key

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License

MIT License © 2025 Anthony Lamelas