userpic_as_gh_generator

userpic_as_gh_generator.py

import random
from typing import List

from jinja2 import Template

SVG_TEMPLATE = Template("""<?xml version="1.0"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
<svg xmlns="http://www.w3.org/2000/svg" width="467" height="462">
 {% for y_i, dots in enumerate(dots_data) %}{% for x_i, dot in enumerate(dots) %}
 <rect x="{{ x_i * w_size }}" 
  y="{{ y_i * h_size }}"
  width="{{ w_size }}"
  height="{{ h_size }}"
  style="fill:#{% if dot == True %}{{ first_color }}{% else %}{{ second_color }}{% endif %}" />{% endfor %}
 {% endfor %}
</svg>
""")


def random_bool() -> bool:
    return bool(random.randint(0, 1))


def generate_line(width: int):
    line = [random_bool() for i in range(width)]
    if len(set(line)) == 1:
        line = generate_line(width)
    return line


def generate_part(width: int, height: int):
    part = [generate_line(width) for j in range(height)]
    return part


def reverse_part(part):
    return [reversed(i) for i in part]


def concatenate_parts(left_part, spacer, right_part):
    result = list()
    for i, left_line in enumerate(left_part):
        right_line = right_part[i]
        spacer_line = spacer[i]
        line = [*left_line, *spacer_line, *right_line]
        result.append(line)
    return result


def generate_userpic_data(width, height):
    left = generate_part(width // 2, height)
    spacer = generate_part(width % 2, height)
    right = reverse_part(left)
    return concatenate_parts(left, spacer, right)


def encode_userpic_data(data: List[List[bool]]) -> str:
    bytes_data = 0
    width = len(data[0])
    encoded_len = width // 2 + width % 2
    for line in data:
        for value in line[:encoded_len]:
            bytes_data = bytes_data << 1 | int(value)
    encoded_as_int: int = int(f"{bytes_data}{encoded_len:0>2}")
    return f"{encoded_as_int:x}"


def decode_userpic_data(encoded_as_hex: str) -> List[List[bool]]:
    encoded_as_int = int(encoded_as_hex, 16)
    width = encoded_as_int % 100
    encoded_data = encoded_as_int // 100
    width_is_odd = width % 2 == 0
    lines = list()
    while encoded_data:
        line = list()
        for i in range(width):
            line.append(bool(encoded_data & 1))
            encoded_data = encoded_data >> 1
        reversed_left = line if width_is_odd else line[1:]
        lines.insert(0, [*reversed(reversed_left), *line])
    return lines


def write_svg_data(data, h_size: int, w_size: int, first_color: str, second_color: str, filename: str):
    svg_data = SVG_TEMPLATE.render(enumerate=enumerate,
                                   dots_data=data,
                                   h_size=h_size,
                                   w_size=w_size,
                                   first_color=first_color,
                                   second_color=second_color)
    with open(filename, "w") as file:
        file.write(svg_data)


def main():
    width = 8
    height = 8
    h_size = 12
    w_size = 12
    first_color = "000000"
    second_color = "aaaaff"
    userpic_data = generate_userpic_data(width, height)
    write_svg_data(userpic_data, h_size, w_size=w_size, first_color=first_color, second_color=second_color,
                   filename="test.svg", )
    encoded = encode_userpic_data(userpic_data)
    print(userpic_data)
    print(encoded)
    print(decode_userpic_data(encoded))


if __name__ == "__main__":
    main()