view gpp/core/image.py @ 504:b5bd3509e6e6

Made some tweaks to the ajax login javascript. Cleared the inputs on failure so someone won't repeatedly try a bad login. Redirect on lockout so the page will refresh. Set focus on the username box after failure for convenience.
author Brian Neal <bgneal@gmail.com>
date Sat, 03 Dec 2011 16:25:15 +0000
parents 1ba2c6bf6eb7
children
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"""
This file contains common utility functions for manipulating images for
the rest of the applications in the project.
"""
from PIL import ImageFile
from PIL import Image


def parse_image(file):
    """
    Returns a PIL Image from the supplied Django file object.
    Throws IOError if the file does not parse as an image file or some other
    I/O error occurred.

    """
    parser = ImageFile.Parser()
    for chunk in file.chunks():
        parser.feed(chunk)
    image = parser.close()
    return image


def downscale_image_square(image, size):
    """
    Scale an image to the square dimensions given by size (in pixels).
    The new image is returned.
    If the image is already smaller than (size, size) then no scaling
    is performed and the image is returned unchanged.

    """
    # don't upscale
    if (size, size) >= image.size:
        return image

    (w, h) = image.size
    if w > h:
        diff = (w - h) / 2
        image = image.crop((diff, 0, w - diff, h))
    elif h > w:
        diff = (h - w) / 2
        image = image.crop((0, diff, w, h - diff))
    image = image.resize((size, size), Image.ANTIALIAS)
    return image