src/picture/templatetags/picture_tags.py

   1 # This file is part of Wolnelektury, licensed under GNU Affero GPLv3 or later.
   2 # Copyright © Fundacja Nowoczesna Polska. See NOTICE for more information.
   3 #
   4 import logging
   5 from random import randint
   6 from django import template
   7 from django.urls import reverse
   8 from django.utils.cache import add_never_cache_headers
   9 import sorl.thumbnail.default
  10 from catalogue.utils import split_tags
  11 from ..engine import CustomCroppingEngine
  12 from ..models import Picture
  13
  14
  15 register = template.Library()
  16
  17 cropper = CustomCroppingEngine()
  18
  19
  20 @register.inclusion_tag('picture/picture_wide.html', takes_context=True)
  21 def picture_wide(context, picture):
  22     context.update({
  23         'picture': picture,
  24         'main_link': reverse('picture_viewer', args=[picture.slug]),
  25         'request': context.get('request'),
  26         'tags': split_tags(picture.tags),
  27         })
  28     return context
  29
  30
  31 @register.simple_tag()
  32 def area_thumbnail_url(area, geometry):
  33     def to_square(coords):
  34         w = coords[1][0] - coords[0][0]
  35         h = coords[1][1] - coords[0][1]
  36         if w == h:
  37             return coords
  38         elif w > h:
  39             return [[coords[0][0] + w/2 - h/2, coords[0][1]],
  40                     [coords[1][0] - w/2 + h/2, coords[1][1]]]
  41         else:
  42             return [[coords[0][0], coords[0][1] + h/2 - w/2],
  43                     [coords[1][0], coords[1][1] - h/2 + w/2, ]]
  44
  45     # so much for sorl extensibility.
  46     # what to do about this?
  47     _engine = sorl.thumbnail.default.engine
  48     sorl.thumbnail.default.engine = cropper
  49     coords = to_square(area.area)
  50
  51     try:
  52         th = sorl.thumbnail.default.backend.get_thumbnail(
  53             area.picture.image_file,
  54             geometry,
  55             crop="%dpx %dpx %dpx %dpx" % tuple(map(lambda d: max(0, d), tuple(coords[0] + coords[1]))))
  56     except ZeroDivisionError:
  57         return ''
  58     except Exception as e:
  59         logging.exception("Error creating a thumbnail for PictureArea")
  60         return ''
  61
  62     sorl.thumbnail.default.engine = _engine
  63
  64     return th.url
  65
  66
  67 @register.simple_tag
  68 def picture_random_picture(exclude_ids, unless=None):
  69     if unless:
  70         return None
  71     queryset = Picture.objects.exclude(pk__in=exclude_ids).exclude(image_file='')
  72     count = queryset.count()
  73     if count:
  74         return queryset[randint(0, count - 1)]
  75     else:
  76         return None