src/librarian/covers/widgets/background.py

   1 # This file is part of Librarian, licensed under GNU Affero GPLv3 or later.
   2 # Copyright © Fundacja Wolne Lektury. See NOTICE for more information.
   3 #
   4 import io
   5 import time
   6 from urllib.request import urlopen
   7 import PIL.Image
   8 from .base import Widget
   9
  10
  11 class Background(Widget):
  12     transparency = False
  13
  14     def __init__(self, cover, crop_to_square=True):
  15         self.crop_to_square = crop_to_square
  16         super().__init__(cover)
  17
  18     def setup(self):
  19         self.img = None
  20         if self.cover.book_info.cover_url:
  21             while True:
  22                 try:
  23                     data = io.BytesIO(urlopen(self.cover.book_info.cover_url, timeout=3).read())
  24                 except:
  25                     time.sleep(2)
  26                 else:
  27                     break
  28
  29             img = PIL.Image.open(data)
  30
  31             if self.crop_to_square:
  32                 # crop top square.
  33                 if img.size[1] > img.size[0]:
  34                     img = img.crop((0, 0, img.size[0], img.size[0]))
  35                 else:
  36                     left = round((img.size[0] - img.size[1])/2)
  37                     img = img.crop((
  38                         left,
  39                         0,
  40                         left + img.size[1],
  41                         img.size[1]
  42                     ))
  43             self.img = img
  44
  45     def build(self, w, h):
  46         if not self.img:
  47             return
  48         img = self.img
  49         scale = max(
  50             w / img.size[0],
  51             h / img.size[1]
  52         )
  53         img = self.img.resize((
  54             round(scale * img.size[0]),
  55             round(scale * img.size[1]),
  56         ))
  57         img = img.crop((
  58             int((img.size[0] - w) / 2),
  59             0,
  60             w + int((img.size[0] - w) / 2),
  61             h))
  62
  63         return img