app/django/core/files/images.py
author Todd Larsen <tlarsen@google.com>
Tue, 14 Oct 2008 21:39:57 +0000
changeset 329 2d90d49ce78a
parent 323 ff1a9aa48cfd
permissions -rw-r--r--
Add is_featured boolean property to the Work model, so that Works can be designated as "featured" items in various places in the UI. This will be used to allow Sponsors, Programs, and Organizations to select Documents that should be included in their sidebar menus. Perhaps featured "site" Documents, such as site-wide Terms of Service, should probably be listed below the "User (sign-out)" menu, since the User will have to read and agree to these before being allowed to use the site. A collapsable Javascript sidebar is probably going to be needed soon... Patch by: Todd Larsen Review by: to-be-reviewed

"""
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