izurvive_map_scraper.py

#!/usr/bin/env python3

import requests
from multiprocessing.dummy import Pool
from io import BytesIO
from PIL import Image
from tqdm import tqdm
from itertools import product


# URL format
TILE_URL = "http://maps.izurvive.com/maps/CH-Top/1.10.5/tiles/{z}/{x}/{y}.png"
# Zoom level to map x/y size in tiles
ZOOM_LEVELS = {
    1: 1,
    2: 3,
    3: 7,
    4: 15,
    5: 30,
    6: 61
}


def get_tile(zoom, x, y):
    """Get one tile from iZurvive."""
    response = requests.get(TILE_URL.format(z=zoom, x=x, y=y))
    return ((x, y), Image.open(BytesIO(response.content)))


def tile_mapper(args):
    """This would have been an anonymous function in a language that respects
    functional programming..."""
    pbar, *args = args
    ret = get_tile(*args)
    pbar.update(1)
    return ret


def get_map(zoom, n_requests):
    """Get an entire map for a given zoom level."""
    tile_range = range(ZOOM_LEVELS[zoom] + 1)
    n_tiles = len(tile_range)
    total = n_tiles * n_tiles
    pool = Pool(n_requests)

    with tqdm(desc="Downloading Tiles", total=total, unit="tile") as pbar:
        # Construct a generator yielding argument tuples for the mapping func
        args = ((pbar, zoom, x, y) for x, y in product(tile_range, tile_range))
        # Asyncronously map the arguments to tile images
        tiles = pool.map(tile_mapper, args)

    tile_size = tiles[0][1].size  # Assumes all tiles are the same size
    dimensions = (tile_size[0] * n_tiles, tile_size[1] * n_tiles)
    full_map = Image.new("RGB", dimensions)

    for location, tile in tqdm(tiles, desc="Combining Tiles", total=total, unit="tile"):
        # The upper-left pixel coordinates for the tile
        box = (
            location[0] * tile_size[0],
            tile_size[1] * (n_tiles - location[1])
        )
        full_map.paste(tile, box)

    return full_map


chernarus = get_map(zoom=4, n_requests=10)
print("Saving File...")
chernarus.save("chernarus.png")