Image converter script for iPhone app and Android app

image_converter.py

# http://stackoverflow.com/questions/9166400/convert-rgba-png-to-rgb-with-pil
# http://stackoverflow.com/questions/11484204/python-invert-image-with-transparent-background-pil-gimp

import argparse
import StringIO

import Image
import ImageOps

class Command(object):

  def __init__(self):
    parser = argparse.ArgumentParser(description="Image processing")
    parser.add_argument("-i", "--input",
                        help="Input file",
                        required=True)
    parser.add_argument("-o", "--output",
                        help=("Onput file."
                              " If you don't set -o parameter,"
                              " It outputs png image data"))
    parser.add_argument("-v", "--invert",
                        help="Invert image color",
                        action="store_true")
    parser.add_argument("--width",
                        help="Change width",
                        type=int)
    parser.add_argument("--height",
                        help="Change height",
                        type=int)

    args = parser.parse_args()

    image = Image.open(args.input).convert("RGBA")
    (width, height) = image.size

    if args.invert:
      image = self.invert(image)

    if args.width:
      width = args.width

    if args.height:
      height = args.height

    image = image.resize((width, height), Image.ANTIALIAS)

    if args.output:
      image.save(args.output)
    else:
      output = StringIO.StringIO()
      image.save(output, "PNG")
      image_value = output.getvalue()
      output.close()
      print image_value

  def invert(self, image):
    (r, g, b, a) = image.split()

    def f(image):
      return image.point(lambda p: 255 - p)

    (r, g, b) = [f(i) for i in (r, g, b)]
    return Image.merge(image.mode, (r, g, b, a))

if __name__ == "__main__":
  Command()