app.py

import gradio as gr
import os
import threading
import subprocess
import time
import re
from huggingface_hub import hf_hub_download
from handwriting_api import InputData, validate_input
from hand import Hand

# Create img directory if it doesn't exist
os.makedirs("img", exist_ok=True)

# Initialize the handwriting model
hand = Hand()

# Create a function to generate handwriting
def generate_handwriting(
    text, 
    style, 
    bias=0.75, 
    color="#000000",
    stroke_width=2,
    multiline=True,
    transparent_background=True
):
    """Generate handwritten text using the model"""
    try:
        # Process the text
        if multiline:
            lines = text.split('\n')
        else:
            lines = [text]
            
        # Create arrays for parameters
        stroke_colors = [color] * len(lines)
        stroke_widths = [stroke_width] * len(lines)
        biases = [bias] * len(lines)
        styles = [style] * len(lines)
        
        # Process each line to replace slashes with dashes
        sanitized_lines = []
        for line_num, line in enumerate(lines):
            if len(line) > 75:
                return f"Error: Line {line_num+1} is too long (max 75 characters)"
            
            # Replace slashes with dashes
            sanitized_line = line.replace('/', '-').replace('\\', '-')
            sanitized_lines.append(sanitized_line)
        
        data = InputData(
            text='\n'.join(sanitized_lines),
            style=style,
            bias=bias,
            stroke_colors=stroke_colors,
            stroke_widths=stroke_widths
        )
        
        try:
            validate_input(data)
        except ValueError as e:
            return f"Error: {str(e)}"
        
        # Generate the handwriting with sanitized lines
        hand.write(
            filename='img/output.svg',
            lines=sanitized_lines,
            biases=biases,
            styles=styles,
            stroke_colors=stroke_colors,
            stroke_widths=stroke_widths
        )
        
        # Read the generated SVG
        with open("img/output.svg", "r") as f:
            svg_content = f.read()
            
        # If transparent background is requested, modify the SVG
        if transparent_background:
            # Remove the background rectangle or make it transparent
            pattern = r'<rect[^>]*?fill="white"[^>]*?>'
            if re.search(pattern, svg_content):
                svg_content = re.sub(pattern, '', svg_content)
            
            # Write the modified SVG back
            with open("img/output.svg", "w") as f:
                f.write(svg_content)
            
        return svg_content
    except Exception as e:
        return f"Error: {str(e)}"

def export_to_png(svg_content):
    """Convert SVG to transparent PNG using CairoSVG and Pillow for robust transparency"""
    try:
        import cairosvg
        from PIL import Image
        
        if not svg_content or svg_content.startswith("Error:"):
            return None
        
        # Modify the SVG to ensure the background is transparent
        # Remove any white background rectangle
        pattern = r'<rect[^>]*?fill="white"[^>]*?>'
        if re.search(pattern, svg_content):
            svg_content = re.sub(pattern, '', svg_content)
        
        # Save the modified SVG to a temporary file
        with open("img/temp.svg", "w") as f:
            f.write(svg_content)
            
        # Convert SVG to PNG with transparency using CairoSVG
        cairosvg.svg2png(
            url="img/temp.svg", 
            write_to="img/output_temp.png", 
            scale=2.0,
            background_color="none"  # This ensures transparency
        )
        
        # Additional processing with Pillow to ensure transparency
        img = Image.open("img/output_temp.png")
        
        # Convert to RGBA if not already
        if img.mode != 'RGBA':
            img = img.convert('RGBA')
        
        # Create a transparent canvas
        transparent_img = Image.new('RGBA', img.size, (0, 0, 0, 0))
        
        # Process the image data to ensure white is transparent
        datas = img.getdata()
        new_data = []
        
        for item in datas:
            # If pixel is white or near-white, make it transparent
            if item[0] > 240 and item[1] > 240 and item[2] > 240:
                new_data.append((255, 255, 255, 0))  # Transparent
            else:
                new_data.append(item)  # Keep original color
        
        transparent_img.putdata(new_data)
        transparent_img.save("img/output.png", "PNG")
        
        # Clean up the temporary file
        try:
            os.remove("img/output_temp.png")
        except:
            pass
        
        return "img/output.png"
    except Exception as e:
        print(f"Error converting to PNG: {str(e)}")
        return None

def generate_lyrics_sample():
    """Generate a sample using lyrics"""
    from lyrics import all_star
    return all_star.split("\n")[0:4]
    
def generate_handwriting_wrapper(
    text, 
    style, 
    bias, 
    color, 
    stroke_width,
    multiline=True
):
    svg = generate_handwriting(text, style, bias, color, stroke_width, multiline)
    png_path = export_to_png(svg)
    return svg, png_path

css = """
.container {max-width: 900px; margin: auto;}
.output-container {min-height: 300px;}
.gr-box {border-radius: 8px; box-shadow: 0 4px 6px rgba(0,0,0,0.1);}
.footer {text-align: center; margin-top: 20px; font-size: 0.8em; color: #666;}
"""

with gr.Blocks(css=css) as demo:
    gr.Markdown("# 🖋️ Handwriting Synthesis")
    gr.Markdown("Generate realistic handwritten text using neural networks.")
    
    with gr.Row():
        with gr.Column(scale=2):
            text_input = gr.Textbox(
                label="Text Input",
                placeholder="Enter text to convert to handwriting...",
                lines=5,
                max_lines=10,
            )
            
            with gr.Row():
                with gr.Column(scale=1):
                    style_select = gr.Slider(
                        minimum=0, 
                        maximum=12, 
                        step=1, 
                        value=9, 
                        label="Handwriting Style"
                    )
                with gr.Column(scale=1):
                    bias_slider = gr.Slider(
                        minimum=0.5, 
                        maximum=1.0, 
                        step=0.05, 
                        value=0.75, 
                        label="Neatness (Higher = Neater)"
                    )
            
            with gr.Row():
                with gr.Column(scale=1):
                    color_picker = gr.ColorPicker(
                        label="Ink Color", 
                        value="#000000"
                    )
                with gr.Column(scale=1):
                    stroke_width = gr.Slider(
                        minimum=1, 
                        maximum=4, 
                        step=0.5, 
                        value=2, 
                        label="Stroke Width"
                    )
            
            with gr.Row():
                generate_btn = gr.Button("Generate Handwriting", variant="primary")
                clear_btn = gr.Button("Clear")
            
            with gr.Accordion("Examples", open=False):
                sample_btn = gr.Button("Insert Sample Text")
            
        with gr.Column(scale=3):
            output_svg = gr.HTML(label="Generated Handwriting (SVG)", elem_classes=["output-container"])
            output_png = gr.Image(type="filepath", label="Generated Handwriting (PNG)", elem_classes=["output-container"])
            
            with gr.Row():
                download_svg_btn = gr.Button("Download SVG")
                download_png_btn = gr.Button("Download PNG")
    
    gr.Markdown("""
    ### Tips:
    - Try different styles (0-12) to get various handwriting appearances
    - Adjust the neatness slider to make writing more or less tidy
    - Each line should be 75 characters or less
    - The model works best for English text
    - Forward slashes (/) and backslashes (\\) will be replaced with dashes (-)
    - PNG output has transparency for easy integration into other documents
    """)
    
    gr.Markdown("""
    <div class="footer">
    Created with Gradio • 
    </div>
    """)
    
    # Define interactions
    generate_btn.click(
        fn=generate_handwriting_wrapper,
        inputs=[text_input, style_select, bias_slider, color_picker, stroke_width],
        outputs=[output_svg, output_png]
    )
    
    clear_btn.click(
        fn=lambda: ("", 9, 0.75, "#000000", 2),
        inputs=None,
        outputs=[text_input, style_select, bias_slider, color_picker, stroke_width]
    )
    
    sample_btn.click(
        fn=lambda: ("\n".join(generate_lyrics_sample())),
        inputs=None,
        outputs=[text_input]
    )
    
    download_svg_btn.click(
        fn=lambda x: x,
        inputs=[output_svg],
        outputs=[gr.File(label="Download SVG", file_count="single", file_types=[".svg"])]
    )
    
    download_png_btn.click(
        fn=lambda x: x,
        inputs=[output_png],
        outputs=[gr.File(label="Download PNG", file_count="single", file_types=[".png"])]
    )

if __name__ == "__main__":
    # Set port based on environment variable or default to 7860
    port = int(os.environ.get("PORT", 7860))
    
    # Check if required packages are installed
    missing_packages = []
    try:
        import cairosvg
    except ImportError:
        missing_packages.append("cairosvg")
    
    try:
        from PIL import Image
    except ImportError:
        missing_packages.append("pillow")
    
    if missing_packages:
        print(f"WARNING: The following packages are missing and required for transparent PNG export: {', '.join(missing_packages)}")
        print("Please install them using: pip install " + " ".join(missing_packages))
    else:
        print("All required packages are installed and ready for transparent PNG export")
    
    demo.launch(server_name="0.0.0.0", server_port=port)