# tk_flippant_spiral_grayscale.py

# tk_flippant_spiral_grayscale.py

import tkinter as tk
from PIL import Image, ImageTk, ImageDraw, ImageFilter
import math

cell_size = 20
SQ = 400 // cell_size * cell_size
GRID = SQ // cell_size
CENTER = (GRID - 1) / 2

rr = tk.Tk()
rr.geometry('+0+0')

cv = tk.Canvas(rr, width=SQ, height=SQ, bg='black')
cv.pack(side='left')

canvas_image_id = cv.create_image(0, 0, anchor='nw')

MIN_SPEED = 0.0001
MAX_SPEED = 5.0

grays = []
def z(r, g, b):
    grays.append(f"#{r:02X}{g:02X}{b:02X}")
r, g, b = 255, 0, 0
for i in range(256):
    z(i, i, i)
grays = grays[::-1] + grays[1:-1]

lc = len(grays) - 1

img = Image.new('RGB', (SQ, SQ), (0, 0, 0))
draw = ImageDraw.Draw(img)

max_dist = math.hypot(CENTER, CENTER)
order = sorted(
    [(x, y) for y in range(GRID) for x in range(GRID)],
    key=lambda xy: (
        math.hypot(xy[0] - CENTER, xy[1] - CENTER) / max_dist,
        math.atan2(xy[1] - CENTER, xy[0] - CENTER)
    )
)

speeds = [0.0] * (GRID * GRID)
for i, (x, y) in enumerate(order):
    speeds[y * GRID + x] = MIN_SPEED + (MAX_SPEED - MIN_SPEED) * (1.0 - i / ((GRID * GRID) - 1))

cells = [0.0] * (GRID * GRID)

while 1:
    i = 0
    for y in range(GRID):
        for x in range(GRID):
            cells[i] += speeds[i]

            if cells[i] >= lc:
                cells[i] = lc
                speeds[i] *= -1
            elif cells[i] <= 0:
                cells[i] = 0
                speeds[i] *= -1

            col = grays[int(cells[i])]
            x0 = x * cell_size
            y0 = y * cell_size

            draw.rectangle(
                (x0, y0, x0 + cell_size, y0 + cell_size),
                fill=col
            )

            i += 1

    img_out = img.filter(ImageFilter.GaussianBlur(radius=50 * 0.2))

    tk_img = ImageTk.PhotoImage(img_out)
    cv.itemconfig(canvas_image_id, image=tk_img)
    cv.tk_img = tk_img

    rr.update_idletasks()
    rr.update()