Fix Membership.__unicode__.

[xnet] / xnet / utils / images / fields.py

# -*- encoding: utf-8 -*-
"""
django-thumbs by Antonio Melé
Modified by Arthur Darcet to support on demand resizing
"""
from django.db.models import ImageField
from django.db.models.fields.files import ImageFieldFile
from PIL import Image
from django.core.files.base import ContentFile
import cStringIO, re


def generate_thumb(img, thumb_size, format):
    img.seek(0) # see http://code.djangoproject.com/ticket/8222 for details
    image = Image.open(img)
    if image.mode not in ('L', 'RGB'):
        image = image.convert('RGB')
    thumb_w, thumb_h = thumb_size
    if thumb_w == thumb_h and False:
        xsize, ysize = image.size
        minsize = min(xsize,ysize)
        xnewsize = (xsize-minsize)/2
        ynewsize = (ysize-minsize)/2
        image2 = image.crop((xnewsize, ynewsize, xsize-xnewsize, ysize-ynewsize))
        image2.load()
        image2.thumbnail(thumb_size, Image.ANTIALIAS)
    else:
        image2 = image
        image2.thumbnail(thumb_size, Image.ANTIALIAS)
    io = cStringIO.StringIO()
    if format.upper()=='JPG':
        format = 'JPEG'
    image2.save(io, format)
    return ContentFile(io.getvalue())


class ImageWithThumbsFieldFile(ImageFieldFile):
    @staticmethod
    def _get_for_size(s, (w,h)):
        split = s.rsplit('.',1)
        return u'{}.{}x{}.{}'.format(split[0],w,h,split[1])

    def __getattr__(self, attr):
        s = attr.split('url_')
        if len(s) != 2 or 'x' not in s[1]:
            raise AttributeError
        if not self.name:
            raise AttributeError('The picture has no file associated with it.')
        size = map(int, s[1].split('x',1))
        name = ImageWithThumbsFieldFile._get_for_size(self.name, size)
        url = ImageWithThumbsFieldFile._get_for_size(self.url, size)
        if not self.storage.exists(name):
            thumb_content = generate_thumb(self, size, name.rsplit('.',1)[1])
            self.storage.save(name, thumb_content)
        return url

    def delete(self, save=True):
        directory, name = self.name.rsplit('/', 1)
        _, files = self.storage.listdir(directory)
        reg = re.compile(r'{}.[0-9]+x[0-9]+.{}'.format(*name.rsplit('.',1)))
        for f in files:
            if reg.match(f):
                self.storage.delete(u'{}/{}'.format(directory, f))
        super(ImageWithThumbsFieldFile, self).delete(save)


class ImageWithThumbsField(ImageField):
    attr_class = ImageWithThumbsFieldFile
    """
    Usage example:
    ==============
    photo = ImageWithThumbsField(upload_to='images', sizes=((125,125),(300,200),)

    To retrieve image URL, exactly the same way as with ImageField:
        my_object.photo.url
    To retrieve thumbnails URL's just add the size to it:
        my_object.photo.url_125x125
        my_object.photo.url_300x200

    Note: The 'sizes' attribute is not required. If you don't provide it,
    ImageWithThumbsField will act as a normal ImageField

    How it works:
    =============
    For each size in the 'sizes' atribute of the field it generates a
    thumbnail with that size and stores it following this format:

    available_filename.[width]x[height].extension

    Where 'available_filename' is the available filename returned by the storage
    backend for saving the original file.

    Following the usage example above: For storing a file called "photo.jpg" it saves:
    photo.jpg          (original file)
    photo.125x125.jpg  (first thumbnail)
    photo.300x200.jpg  (second thumbnail)

    With the default storage backend if photo.jpg already exists it will use these filenames:
    photo_.jpg
    photo_.125x125.jpg
    photo_.300x200.jpg

    Note: django-thumbs assumes that if filename "any_filename.jpg" is available
    filenames with this format "any_filename.[widht]x[height].jpg" will be available, too.

    To do:
    ======
    Add method to regenerate thubmnails

    """
    def __init__(self, verbose_name=None, name=None, width_field=None, height_field=None, **kwargs):
        self.verbose_name=verbose_name
        self.name=name
        self.width_field=width_field
        self.height_field=height_field
        super(ImageField, self).__init__(**kwargs)