Image.py

# -*- coding: utf-8 -*-
# 
# # MIT License
# 
# Copyright (c) 2025 Michael J Simms
# 
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
# 
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

from io import BytesIO
from PIL import Image

def to_webp_scaled_50(image_bytes: bytes, *, quality: int = 80, lossless: bool = False) -> bytes:
    """Converts an in-memory image (bytes) to WebP scaled to 50%. Returns WebP bytes."""
    with Image.open(BytesIO(image_bytes)) as img:

        # Calculate 50% size
        new_w = max(1, img.width // 2)
        new_h = max(1, img.height // 2)

        # High-quality downscale
        img_resized = img.resize((new_w, new_h), Image.Resampling.LANCZOS)

        # Write to an in-memory buffer as WebP
        out = BytesIO()
        img_resized.save(
            out,
            format="WEBP",
            quality=quality,    # 0-100 (ignored when lossless=True)
            lossless=lossless,  # set True for lossless WebP
            method=6,           # 0-6, slower = better compression
            optimize=True
        )
        return out.getvalue()