#!/usr/bin/env python
import getopt
from PIL import Image, ImageDraw
import sys
import textwrap


UNLIMITED = -1
DEFAULT_WIDTH = 128
DEFAULT_HEIGHT = 96
DEFAULT_FORMAT = 'png'


def generate_png_sequence(width, height, frames, format):
    im = Image.new('RGB', (width, height))
    draw = ImageDraw.Draw(im)

    for f in range(frames):
        for x in range(width):
            color = 'hsl(%d,100%%,50%%)' % (
                int(((x + f) * 360. / width) % 360), )
            draw.line([(x, 0), (x, height)], fill=color)
        im.save(sys.stdout, format)


def usage():
    print textwrap.dedent("""\
        Use gen_png_seq.py (-s|--size=%dx%d) -f|--frames=30 (--format=%s) (-h|--help)

        size: <width>x<height> of the generated PNGs. %dx%d by default.
        frames: Number of png images to generate. %d for unlimited. REQUIRED!
        format: One of png or jpeg.
        help: Show usage.
    """ % (DEFAULT_WIDTH, DEFAULT_HEIGHT, DEFAULT_FORMAT, DEFAULT_WIDTH,
        DEFAULT_HEIGHT, UNLIMITED))


def main():
    try:
        opts, args = getopt.getopt(sys.argv[1:], 's:f:h',
                                   ['size=', 'frames=', 'format='])
    except getopt.GetoptError, err:
        print str(err)
        usage()
        sys.exit(1)

    width = DEFAULT_WIDTH
    height = DEFAULT_HEIGHT
    frames = 0
    format = DEFAULT_FORMAT
    for o, a in opts:
        if o in ('-s', '--size'):
            width, height = [int(x) for x in a.split('x')]
        elif o in ('-h', '--help'):
            usage()
            sys.exit(0)
        elif o in ('-f', '--frames'):
            frames = int(a)
        elif o in ('--format',):
            format = a
        else:
            assert False, "unhandled option"

    if not frames:
        usage()
        sys.exit(0)

    generate_png_sequence(width, height, frames, format)


if __name__ == '__main__':
    main()