app.py

import gradio as gr
from transformers import TrOCRProcessor, VisionEncoderDecoderModel
import torch
import subprocess
import json
from PIL import Image, ImageDraw
import os
import tempfile
import numpy as np

# Dictionary of model names and their corresponding HuggingFace model IDs
MODEL_OPTIONS = {
    "Microsoft Handwritten": "microsoft/trocr-base-handwritten",
    "Medieval Base": "medieval-data/trocr-medieval-base",
    "Medieval Latin Caroline": "medieval-data/trocr-medieval-latin-caroline",
    "Medieval Castilian Hybrida": "medieval-data/trocr-medieval-castilian-hybrida",
    "Medieval Humanistica": "medieval-data/trocr-medieval-humanistica",
    "Medieval Textualis": "medieval-data/trocr-medieval-textualis",
    "Medieval Cursiva": "medieval-data/trocr-medieval-cursiva",
    "Medieval Semitextualis": "medieval-data/trocr-medieval-semitextualis",
    "Medieval Praegothica": "medieval-data/trocr-medieval-praegothica",
    "Medieval Semihybrida": "medieval-data/trocr-medieval-semihybrida",
    "Medieval Print": "medieval-data/trocr-medieval-print"
}

# Global variables to store the current model and processor
current_model = None
current_processor = None
current_model_name = None

def load_model(model_name):
    global current_model, current_processor, current_model_name
    
    if model_name != current_model_name:
        model_id = MODEL_OPTIONS[model_name]
        current_processor = TrOCRProcessor.from_pretrained(model_id)
        current_model = VisionEncoderDecoderModel.from_pretrained(model_id)
        current_model_name = model_name
        
        # Move model to GPU if available, else use CPU
        device = torch.device('cuda' if torch.cuda.is_available() else 'cpu')
        current_model = current_model.to(device)
    
    return current_processor, current_model

def process_image(image, model_name):
    # Save the uploaded image to a temporary file
    with tempfile.NamedTemporaryFile(suffix=".jpg", delete=False) as temp_img:
        image.save(temp_img, format="JPEG")
        temp_img_path = temp_img.name

    # Run Kraken for line detection
    lines_json_path = "lines.json"
    kraken_command = f"kraken -i {temp_img_path} {lines_json_path} binarize segment -bl"
    subprocess.run(kraken_command, shell=True, check=True)

    # Load the lines from the JSON file
    with open(lines_json_path, 'r') as f:
        lines_data = json.load(f)

    processor, model = load_model(model_name)

    # Determine device
    device = torch.device('cuda' if torch.cuda.is_available() else 'cpu')

    # Process each line
    transcriptions = []
    for line in lines_data['lines']:
        # Extract line coordinates
        x1, y1 = line['baseline'][0]
        x2, y2 = line['baseline'][-1]
        
        # Crop the line from the original image
        line_image = image.crop((x1, y1, x2, y2))

        # Convert to grayscale if it's not already
        if line_image.mode != 'L':
            line_image = line_image.convert('L')

        # Convert to numpy array and normalize
        line_image_np = np.array(line_image).astype(np.float32) / 255.0
        line_image_np = np.expand_dims(line_image_np, axis=0)  # Add channel dimension

        # Prepare image for TrOCR
        pixel_values = processor(images=line_image_np, return_tensors="pt").pixel_values
        pixel_values = pixel_values.to(device)

        # Generate (no beam search)
        with torch.no_grad():
            generated_ids = model.generate(pixel_values)

        # Decode
        generated_text = processor.batch_decode(generated_ids, skip_special_tokens=True)[0]
        transcriptions.append(generated_text)

    # Clean up temporary files
    os.unlink(temp_img_path)
    os.unlink(lines_json_path)

    # Create an image with bounding boxes
    draw = ImageDraw.Draw(image)
    for line in lines_data['lines']:
        coords = line['baseline']
        draw.line(coords, fill="red", width=2)

    return image, "\n".join(transcriptions)

# Gradio interface
with gr.Blocks() as iface:
    gr.Markdown("# Medieval Document Transcription")
    gr.Markdown("Upload an image of a medieval document and select a model to transcribe it. The tool will detect lines and transcribe each line separately.")
    
    with gr.Row():
        input_image = gr.Image(type="pil", label="Input Image")
        model_dropdown = gr.Dropdown(choices=list(MODEL_OPTIONS.keys()), label="Select Model", value="Medieval Base")
    
    with gr.Row():
        output_image = gr.Image(type="pil", label="Detected Lines")
        transcription_output = gr.Textbox(label="Transcription", lines=10)
    
    submit_button = gr.Button("Transcribe")
    submit_button.click(fn=process_image, inputs=[input_image, model_dropdown], outputs=[output_image, transcription_output])

iface.launch(share=True)