pi1_to_font.py

if __name__ == '__main__':
    import struct, sys

    pi1 = open(sys.argv[1], "rb")
    header = pi1.read(34)       # skip the header data
    pi1_bytes = pi1.read(32000) # We just want the pixeles
    pi1.close()

    out_bytes = bytearray(256 * 8)
    for b in range(0, 256*8):

        # Work out which character this is from
        char = b % 256              # Character N
        row_in_char = b / 256       # Row 0..7
        if char < 32:
            continue

        # Adjust into "Spiny range" where the source byte
        # for char 32 is at position 0
        spiny_char = char - 32

        # Work out where to get the source pixel data from
        output_x_col = (spiny_char % 40)        # range 0-39
        output_y_row = ((spiny_char / 40) * 8) + row_in_char

        # Convert from 0,1,2,3 etc to 0,1,8,9 to look up the correct chunk
        x_byte_offset = (output_x_col / 2) * 8 + (output_x_col & 1)

        # Read the value and stick it in the output
        # NOTE: this reads the first bitplane i.e. value of 1
        out_bytes[b] = pi1_bytes[160 * output_y_row + x_byte_offset]
    
    out_fh = open(sys.argv[2], "wb")
    out_fh.write(out_bytes)
    out_fh.close()