andrewgiessel

import numpy as np
import base64, zlib, struct
from IPython.display import HTML

def write_png(buf, width, height):
    """ buf: must be bytes or a bytearray in py3, a regular string in py2. formatted RGBARGBA... """
    
    # reverse the vertical line order and add null bytes at the start
    width_byte_4 = width * 4
    raw_data = b''.join(b'\x00' + buf[span:span + width_byte_4]