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             close = self.closed

    25             self.open()

    26             self._dimensions_cache = get_image_dimensions(self)

    27             if close:

    28                 self.close()

    29         return self._dimensions_cache

    30 

    31 def get_image_dimensions(file_or_path):

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

    33     from PIL import ImageFile as PILImageFile

    34     p = PILImageFile.Parser()

    35     close = False

    36     if hasattr(file_or_path, 'read'):

    37         file = file_or_path

    38     else:

    39         file = open(file_or_path, 'rb')

    40         close = True

    41     try:

    42         while 1:

    43             data = file.read(1024)

    44             if not data:

    45                 break

    46             p.feed(data)

    47             if p.image:

    48                 return p.image.size

    49         return None

    50     finally:

    51         if close:

    52             file.close()