import tkinter as tk

r = tk.Tk()
r.withdraw()
hexes = '0123456789abcdef'
enex = list(zip(range(16), hexes))
              
def rval(col):
    return r.winfo_rgb(col)[0]

# ON WINDOWS:
# 1 hex digit is quadrupled and value multiplied by 17 * 257.
print(all(
    rval(f'#{x}00') == rval(f'#{x}{x}{x}{x}00000000') == i * 17 * 257
        for i, x in enex))

# 2 hex digits are doubled and value multiplied by 257
print(all(
    rval(f'#{x}{y}0000') == rval(f'#{x}{y}{x}{y}00000000') == (i*16 + j) * 257
        for i, x in enex for j, y in enex))

# 3 or 4 hex digits are truncated to 2 leading digits (doubled
print(all(
    rval(f'#{x}{y}{t}{u}00000000') == rval(f'#{x}{y}0000000000')
        for x in hexes for y in hexes for t in hexes for u in hexes))

# Prints True, True, and seconds later, True.