from PIL import Image
from PIL import ImageChops
from PIL import ImageDraw


async def crop_to_circle(im):
    bigsize = (im.size[0] * 3, im.size[1] * 3)
    mask = Image.new('L', bigsize, 0)
    ImageDraw.Draw(mask).ellipse((0, 0) + bigsize, fill='white')
    mask = mask.resize(im.size, Image.ANTIALIAS)
    mask = ImageChops.darker(mask, im.split()[-1])
    im.putalpha(mask)