src/picture/templatetags/picture_tags.py

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