utils.py

import numpy as np
from PIL import Image, ImageOps
import io
import base64

def resize_image(image, max_size=1024):
    """
    Resize image to maximum dimension while maintaining aspect ratio.
    
    Args:
        image (PIL.Image): Input image
        max_size (int): Maximum dimension size
    
    Returns:
        PIL.Image: Resized image
    """
    if image is None:
        return None
    
    # Get current dimensions
    width, height = image.size
    
    # Calculate new dimensions
    if max(width, height) > max_size:
        if width > height:
            new_width = max_size
            new_height = int(height * max_size / width)
        else:
            new_height = max_size
            new_width = int(width * max_size / height)
        
        image = image.resize((new_width, new_height), Image.Resampling.LANCZOS)
    
    return image

def convert_to_rgba(image):
    """
    Convert image to RGBA format with transparency.
    
    Args:
        image (PIL.Image): Input image
    
    Returns:
        PIL.Image: RGBA image
    """
    if image is None:
        return None
    
    if image.mode != 'RGBA':
        image = image.convert('RGBA')
    
    return image

def image_to_base64(image):
    """
    Convert PIL image to base64 string.
    
    Args:
        image (PIL.Image): Input image
    
    Returns:
        str: Base64 encoded image
    """
    if image is None:
        return None
    
    buffer = io.BytesIO()
    image.save(buffer, format='PNG')
    buffer.seek(0)
    
    return base64.b64encode(buffer.getvalue()).decode('utf-8')

def base64_to_image(base64_string):
    """
    Convert base64 string to PIL image.
    
    Args:
        base64_string (str): Base64 encoded image
    
    Returns:
        PIL.Image: Decoded image
    """
    if base64_string is None:
        return None
    
    try:
        image_bytes = base64.b64decode(base64_string)
        return Image.open(io.BytesIO(image_bytes))
    except Exception as e:
        raise ValueError(f"Invalid base64 image data: {str(e)}")

def validate_image(image):
    """
    Validate that the input is a proper image.
    
    Args:
        image: Input to validate
    
    Returns:
        bool: True if valid image
    """
    if image is None:
        return False
    
    try:
        if isinstance(image, np.ndarray):
            image = Image.fromarray(image)
        
        if hasattr(image, 'save'):
            # Test if image can be saved
            buffer = io.BytesIO()
            image.save(buffer, format='PNG')
            return True
        
        return False
    except Exception:
        return False

def create_transparent_background(image, color=(255, 255, 255)):
    """
    Replace transparent areas with specified color.
    
    Args:
        image (PIL.Image): Input image
        color (tuple): RGB color to use as background
    
    Returns:
        PIL.Image: Image with colored background
    """
    if image is None:
        return None
    
    # Ensure image is RGBA
    if image.mode != 'RGBA':
        image = image.convert('RGBA')
    
    # Create background
    background = Image.new('RGB', image.size, color)
    background.paste(image, mask=image.split()[-1])  # Use alpha channel as mask
    
    return background

def optimize_for_web(image, quality=85):
    """
    Optimize image for web use.
    
    Args:
        image (PIL.Image): Input image
        quality (int): JPEG quality (1-100)
    
    Returns:
        PIL.Image: Optimized image
    """
    if image is None:
        return None
    
    # Convert to RGB if no transparency
    if image.mode in ('RGBA', 'LA') and 'transparency' not in image.info:
        background = Image.new('RGB', image.size, (255, 255, 255))
        background.paste(image, mask=image.split()[-1] if image.mode == 'RGBA' else None)
        image = background
    
    return image