README.md

---
title: Searchable PDF Generator with OCR (Hunyuan-DiT)
emoji: 📄
colorFrom: blue
colorTo: purple
sdk: gradio
sdk_version: "4.36.1"
app_file: app.py
pinned: false
---

# Searchable PDF Generator with OCR + Layout Preservation (Hunyuan-DiT)

This Hugging Face Space converts image-based PDFs and images into layout-preserving, searchable PDFs using the Hunyuan-DiT model for high-quality visual understanding and text extraction.

## Objective

To develop a robust system that accepts PDFs or images, processes each page using Hunyuan-DiT for advanced OCR, extracts text with precise positional data, and reconstructs a searchable PDF that exactly mirrors the original visual layout, including page size, coordinates, fonts, bounding boxes, multi-column structures, tables, and embedded graphical elements.

## Features

- **Input Flexibility**: Accepts PDF documents and various image formats (PNG, JPG, TIFF).
- **High-Quality OCR**: Utilizes Hunyuan-DiT for superior visual understanding and text extraction.
- **Layout Preservation**: Ensures the output PDF maintains the original document's layout, including:
    - Page size
    - Layout and coordinates
    - Approximate fonts
    - Bounding boxes for text
    - Multi-column structures
    - Tables and embedded graphical elements
- **Searchable Output**: Generates a multi-page searchable PDF with invisible text layers placed at exact coordinates over the original scanned image.
- **Preview Functionality**: Provides a preview of extracted OCR, highlighting bounding boxes.
- **Downloadable Results**: Offers a direct download link for the final searchable PDF.

## Architecture

1.  **User Uploads**: Users upload a PDF or image files via a Gradio interface.
2.  **PDF to Image Conversion**: PDFs are converted into individual page images at 300–400 DPI.
3.  **Hunyuan-DiT OCR**: Each page image is fed into the Hunyuan-DiT model for OCR and layout extraction, producing structured JSON output including words, bounding boxes, line grouping, reading order, block segmentation, and confidence scores.
4.  **PDF Assembly**: An invisible text layer is meticulously assembled on top of the original image for each page.
5.  **Final PDF Generation**: A multi-page searchable PDF is generated.
6.  **Download**: The user can download the final searchable PDF.

## Error Handling

The system includes robust error handling for:

- Corrupted PDF inputs.
- Multi-language input (handled by Hunyuan-DiT).
- Pages exceeding maximum size (>10,000 pixels in any dimension).

## Setup and Usage

### Prerequisites

Ensure you have Python 3.8+ installed.

### Installation

1.  Clone the repository:
    ```bash
    git clone <repository_url>
    cd <repository_name>
    ```
2.  Create a virtual environment (recommended):
    ```bash
    python -m venv venv
    source venv/bin/activate  # On Windows: `venv\Scripts\activate`
    ```
3.  Install the required dependencies:
    ```bash
    pip install -r requirements.txt
    ```

### Running the Space

To launch the Gradio application locally:

```bash
python app.py
```

Then, open your web browser and navigate to the address provided by Gradio (usually `http://127.0.0.1:7860`).

## Folder Structure

```
/
├── app.py
├── requirements.txt
├── utils/
│   ├── pdf_to_images.py
│   ├── hunyuan_ocr.py
│   └── pdf_builder.py
└── README.md
```