write a threatening pattern to a pbm

framebuf_pattern_pbm-big2.py

#!/usr/bin/env micropython
# write a threatening pattern to a pbm
# scruss, 2024-11
# MicroPython has framebuf, but no math.isqrt()
# Python3 has no framebuf, but has math.isqrt()

import framebuf
from math import sqrt

WIDTH = 1280 # original target was a 128 x 64 OLED
HEIGHT = 640
buffer = bytearray(round(WIDTH * HEIGHT / 8))
fb = framebuf.FrameBuffer(buffer, WIDTH, HEIGHT, framebuf.MONO_HLSB)


def hlsb2pbm(b, w, h):
    # write out a MONO_HLSB framebuffer's bytearray, b, of size w x h
    # to a NetPBM RAW PBM file
    import time

    ds = "T".join(
        (
            "%4d%02d%02d" % (time.localtime()[0:3]),
            "%02d%02d%02d" % (time.localtime()[3:6]),
        )
    )
    f = open("fb-" + ds + ".pbm", "wb")
    f.write(bytes("P4\n", "UTF-8"))
    f.write(bytes(str(w) + " " + str(h) + "\n", "UTF-8"))
    f.write(b)
    f.close()


# Clear the oled display in case it has junk on it.
fb.fill(0)

for y in range(HEIGHT):
    for x in range(WIDTH):
        p = int(sqrt(x**2 / 160 + y**2 / 160)) % 2
        q = (
            int(sqrt((WIDTH - x) ** 3 / 160 + (HEIGHT - y) ** 2 / 160))
            % 2
        )
        fb.pixel(x, y, p ^ q)

# write to file
hlsb2pbm(buffer, WIDTH, HEIGHT)