1 """

     2 Utility functions for handling images.

     3 

     4 Requires PIL, as you might imagine.

     5 """

     6 

     7 from django.core.files import File

     8 

     9 class ImageFile(File):

    10     """

    11     A mixin for use alongside django.core.files.base.File, which provides

    12     additional features for dealing with images.

    13     """

    14     def _get_width(self):

    15         return self._get_image_dimensions()[0]

    16     width = property(_get_width)

    17 

    18     def _get_height(self):

    19         return self._get_image_dimensions()[1]

    20     height = property(_get_height)

    21 

    22     def _get_image_dimensions(self):

    23         if not hasattr(self, '_dimensions_cache'):

    24             self._dimensions_cache = get_image_dimensions(self)

    25         return self._dimensions_cache

    26 

    27 def get_image_dimensions(file_or_path):

    28     """Returns the (width, height) of an image, given an open file or a path."""

    29     from PIL import ImageFile as PILImageFile

    30     p = PILImageFile.Parser()

    31     if hasattr(file_or_path, 'read'):

    32         file = file_or_path

    33     else:

    34         file = open(file_or_path, 'rb')

    35     while 1:

    36         data = file.read(1024)

    37         if not data:

    38             break

    39         p.feed(data)

    40         if p.image:

    41             return p.image.size

    42     return None