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 PIL import ImageOps
   9 from .base import Widget
  10
  11
  12 class Background(Widget):
  13     transparency = False
  14
  15     def __init__(self, cover, crop_to_square=True):
  16         self.crop_to_square = crop_to_square
  17         super().__init__(cover)
  18
  19     def setup(self):
  20         self.img = None
  21         if self.cover.book_info.cover_url:
  22             while True:
  23                 try:
  24                     data = io.BytesIO(urlopen(self.cover.book_info.cover_url, timeout=3).read())
  25                 except:
  26                     time.sleep(2)
  27                 else:
  28                     break
  29
  30             img = PIL.Image.open(data)
  31             img = ImageOps.exif_transpose(img)
  32
  33             if self.crop_to_square:
  34                 # crop top square.
  35                 if img.size[1] > img.size[0]:
  36                     img = img.crop((0, 0, img.size[0], img.size[0]))
  37                 else:
  38                     left = round((img.size[0] - img.size[1])/2)
  39                     img = img.crop((
  40                         left,
  41                         0,
  42                         left + img.size[1],
  43                         img.size[1]
  44                     ))
  45             self.img = img
  46
  47     def build(self, w, h):
  48         if not self.img:
  49             return
  50         img = self.img
  51         scale = max(
  52             w / img.size[0],
  53             h / img.size[1]
  54         )
  55         img = self.img.resize((
  56             round(scale * img.size[0]),
  57             round(scale * img.size[1]),
  58         ))
  59         img = img.crop((
  60             int((img.size[0] - w) / 2),
  61             0,
  62             w + int((img.size[0] - w) / 2),
  63             h))
  64
  65         return img