app/django/core/files/images.py
author Sverre Rabbelier <srabbelier@gmail.com>
Mon, 03 Nov 2008 19:47:02 +0000
changeset 439 0658c3c9a9dc
parent 323 ff1a9aa48cfd
permissions -rw-r--r--
Minor fixes needed for generic key name We no longer try to retreive an entity when there are unset fields. This sort of makes 'getIfFields' obsolete, since we check if fields now anyway. This is needed because getKeyFieldsFromDict expects the fields to be set. Also a minor fix in a Django template so that the generic 'edit' page has a working delete button again.

"""
Utility functions for handling images.

Requires PIL, as you might imagine.
"""

from django.core.files import File

class ImageFile(File):
    """
    A mixin for use alongside django.core.files.base.File, which provides
    additional features for dealing with images.
    """
    def _get_width(self):
        return self._get_image_dimensions()[0]
    width = property(_get_width)

    def _get_height(self):
        return self._get_image_dimensions()[1]
    height = property(_get_height)

    def _get_image_dimensions(self):
        if not hasattr(self, '_dimensions_cache'):
            self._dimensions_cache = get_image_dimensions(self)
        return self._dimensions_cache

def get_image_dimensions(file_or_path):
    """Returns the (width, height) of an image, given an open file or a path."""
    from PIL import ImageFile as PILImageFile
    p = PILImageFile.Parser()
    if hasattr(file_or_path, 'read'):
        file = file_or_path
    else:
        file = open(file_or_path, 'rb')
    while 1:
        data = file.read(1024)
        if not data:
            break
        p.feed(data)
        if p.image:
            return p.image.size
    return None