apps/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 from django import template
   6 from django.core.urlresolvers import reverse
   7 from catalogue.utils import split_tags
   8 from ..engine import CustomCroppingEngine
   9 import sorl.thumbnail.default
  10 import logging
  11
  12 register = template.Library()
  13
  14 cropper = CustomCroppingEngine()
  15
  16 @register.inclusion_tag('picture/picture_wide.html', takes_context=True)
  17 def picture_wide(context, picture):
  18     context.update({
  19         'picture': picture,
  20         'main_link': reverse('picture_viewer', args=[picture.slug]),
  21         'request': context.get('request'),
  22         'tags': split_tags(picture.tags),
  23         })
  24     return context
  25
  26
  27 @register.simple_tag()
  28 def area_thumbnail_url(area, geometry):
  29     def to_square(coords):
  30         w = coords[1][0] - coords[0][0]
  31         h = coords[1][1] - coords[0][1]
  32         if w == h:
  33             return coords
  34         elif w > h:
  35             return [[coords[0][0] + w/2 - h/2, coords[0][1]],
  36                     [coords[1][0] - w/2 + h/2, coords[1][1]]]
  37         else:
  38             return [[coords[0][0], coords[0][1] + h/2 - w/2],
  39                     [coords[1][0], coords[1][1] - h/2 + w/2, ]]
  40
  41     # so much for sorl extensibility.
  42     # what to do about this?
  43     _engine = sorl.thumbnail.default.engine
  44     sorl.thumbnail.default.engine = cropper
  45     coords = to_square(area.area)
  46
  47     try:
  48         th = sorl.thumbnail.default.backend.get_thumbnail(
  49             area.picture.image_file,
  50             geometry,
  51             crop="%dpx %dpx %dpx %dpx" % tuple(map(lambda d: max(0, d), tuple(coords[0] + coords[1]))))
  52     except Exception, e:
  53         logging.exception("Error creating a thumbnail for PictureArea")
  54         return ''
  55
  56     sorl.thumbnail.default.engine = _engine
  57
  58     return th.url