app/django/core/files/images.py
author Sverre Rabbelier <srabbelier@gmail.com>
Fri, 23 Jan 2009 21:20:33 +0000
changeset 935 09f47e08f805
parent 323 ff1a9aa48cfd
permissions -rw-r--r--
Adust the as_table tag to render a pick link if appropriate The templates are adjusted to pass on a 'reference' value, which is the url_name of the view from which the entity should be picked. The as_table (and related) function(s) construct and then pass on this argument and enable takes_contex so that we have access to the context of the enclosing template. We only extract ReferenceProperties that end with '_link_id' since that is how all RP's are currently named. It is not possible to create a field with the same name as the RP, as GAE will try to interpret it's contents as the key of an entity before even calling any function we can override. Patch by: Sverre Rabbelier

"""
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