#!python
# -*- mode: python; Encoding: utf-8; coding: utf-8 -*-
# Last updated: <2022/06/19 08:44:13 +0900>
"""
Pillow make gradation image.

Windows10 x64 21H2 + Python 3.9.13 64bit + Pillow 9.1.1
"""

from PIL import Image, ImageDraw


def make_gradation_image(w, h):
    im = Image.new("L", (w, h), (128))
    draw = ImageDraw.Draw(im)
    for y in range(16):
        for x in range(16):
            v = y * 16 + x
            x0 = x * w / 16
            y0 = y * h / 16
            x1 = (x + 1) * w / 16 - 1
            y1 = (y + 1) * h / 16 - 1
            # draw.rectangle((x0, y0, x1, y1), fill=(v), outline=(0))
            draw.rectangle((x0, y0, x1, y1), fill=(v), outline=None)
    return im


def main():
    im = make_gradation_image(512, 512)
    im.show()
    im.save("gradation.png")


if __name__ == '__main__':
    main()