ansi grafx demo

ansi_grafx.py

import io
import itertools
import shutil
import sys


BLOCK = chr(9608)
ESC = "\x1b["
RST = ESC + "0m"


class IterFile:
    """given an iterator which yields strings,
    return a file like object for reading those strings"""

    def __init__(self, it):
        self._it = it
        self._f = io.StringIO()

    def read(self, length=sys.maxsize):

        try:
            while self._f.tell() < length:
                self._f.write(next(self._it))

        finally:
            self._f.seek(0)
            data = self._f.read(length)

            # save the remainder for next read
            remainder = self._f.read()
            self._f.seek(0)
            self._f.truncate(0)
            self._f.write(remainder)
            return data

        
def move(i, j):
    return ESC + f"{i};{j}H"


def color(i):
    return ESC + f"38;5;{i}m"


def terminal_size():
    return shutil.get_terminal_size()


pixels = [color(i) + BLOCK for i in range(256)]
columns, rows = terminal_size()


def draw(phase):
    sys.stdout.write(move(0, 0))
    pixel_gen = (pixels[(i + phase) % 256] for i in range(rows * columns))
    f = IterFile(pixel_gen)
    shutil.copyfileobj(f, sys.stdout)


if __name__ == "__main__":
    for i in itertools.count():
        draw(i)