masha_laba_pil.py

import sys
import argparse

import Image
import ImageFilter
from numpy import exp, mgrid


def resize(args):
    image = Image.open(args.image)
    new_size = [s * args.n for s in image.size]
    image = image.resize(new_size)
    image.save(generate_new_filename(args.image, 'resized'), 'JPEG')


def gaus_filter(args):
    image = Image.open(args.image)
    image = image.filter(GAUSSIAN)
    image.save(generate_new_filename(args.image, 'gauss'), 'JPEG')


def gaussian_grid(size=5):
    """
    Create a square grid of integers of gaussian shape
    e.g. gaussian_grid() returns
    array([[ 1,  4,  7,  4,  1],
           [ 4, 20, 33, 20,  4],
           [ 7, 33, 55, 33,  7],
           [ 4, 20, 33, 20,  4],
           [ 1,  4,  7,  4,  1]])
    """
    m = size / 2
    n = m + 1  # remember python is 'upto' n in the range below
    x, y = mgrid[-m:n, -m:n]
    # multiply by a factor to get 1 in the corner of the grid
    # ie for a 5x5 grid   fac*exp(-0.5*(2**2 + 2**2)) = 1
    fac = exp(m ** 2)
    g = fac * exp(-0.5 * (x ** 2 + y ** 2))
    return g.round().astype(int)


class GAUSSIAN(ImageFilter.BuiltinFilter):
    name = "Gaussian"
    gg = gaussian_grid().flatten().tolist()
    filterargs = (5, 5), sum(gg), 0, tuple(gg)


def generate_new_filename(path, word):
    part1, part2 = path.split('.')
    return '%s_%s.%s' % (part1, word, part2)


def get_parser():
    parser = argparse.ArgumentParser(
        epilog="Example usage:\n  python %s gauss image.jpg\n"
        "  python %s resize 3 image.jpg" % (sys.argv[0], sys.argv[0]),
        formatter_class=argparse.RawDescriptionHelpFormatter
    )
    subparsers = parser.add_subparsers()

    parser_res = subparsers.add_parser('resize', help='enlarges imges n times')
    parser_res.add_argument('n', type=int, help='resizing coefficient')
    parser_res.add_argument('image', type=str, help='path to jpg image file')
    parser_res.set_defaults(func=resize)

    parser_filt = subparsers.add_parser('gauss', help='gaussian filter')
    parser_filt.add_argument('image', type=str, help='path to jpg image file')
    parser_filt.set_defaults(func=gaus_filter)

    return parser


def main():
    args = get_parser().parse_args()
    args.func(args)


if __name__ == '__main__':
    main()