auto_format.py

auto_format.py

# Author Ondrej Barta
# [email protected]
# Copyright 2023


from thumbor.filters import BaseFilter, filter_method
from thumbor.utils import logger


# http://css.nothrem.cz/jak-urcit-kvalitu-a-kompresi-jpg-obrazku/
# http://css.nothrem.cz/webp-a-avif/
class Filter(BaseFilter):
    @filter_method(BaseFilter.PositiveNumber, BaseFilter.DecimalNumber)
    async def auto_format(self, base=90, quantifier=0.025):
        accept = self.engine.context.request.headers.get("Accept", "")
        if self.engine.avif_enabled() and "image/avif" in accept:
            self.context.request.format = "avif"
            recalculation = 0.70
            min_quality = 50
        elif "image/webp" in accept:
            self.context.request.format = "webp"
            recalculation = 1.1
            min_quality = 80
        else:
            self.context.request.format = "jpeg"
            recalculation = 1
            min_quality = 50

        image_w, image_h = self.engine.size
        min_size = min(image_w, image_h)
        quality = max(min_quality, (base - min_size * quantifier) * recalculation)

        logger.debug(f"[AUTO FORMAT]: {self.context.request.format} - q: {quality}")

        self.context.request.quality = round(quality)