To demonstrate handling of binary files, we need an interesting binary data format. BMP is an image file format that contains Device Independent Bitmaps. It's simple enough that we can make a BMP file writer from scratch. Place the following code in a module called bmp.py:
# bmp.py"""A module for dealing with BMP bitmap image files."""def write_grayscale(filename, pixels): """Creates and writes a grayscale BMP file. Args: filename: The name of the BMP file to me created. pixels: A rectangular image stored as a sequence of rows. Each row must be an iterable series of integers in the range 0-255. Raises: OSError: If the file couldn't be written. """ height = len(pixels) width = len(pixels[0]) with open(filename, 'wb') as ...
