source.py 文件源码

def __init__(self,
        url="http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png",
        cache_key=None, min_zoom=0, max_zoom=19, tile_size=256,
        image_ext="png",
        attribution="© OpenStreetMap contributors",
        subdomains="abc"):
        super(MapSource, self).__init__()
        if cache_key is None:
            # possible cache hit, but very unlikely
            cache_key = hashlib.sha224(url.encode("utf8")).hexdigest()[:10]
        self.url = url
        self.cache_key = cache_key
        self.min_zoom = min_zoom
        self.max_zoom = max_zoom
        self.tile_size = tile_size
        self.image_ext = image_ext
        self.attribution = attribution
        self.subdomains = subdomains
        self.cache_fmt = "{cache_key}_{zoom}_{tile_x}_{tile_y}.{image_ext}"
        self.dp_tile_size = min(dp(self.tile_size), self.tile_size * 2)
        self.default_lat = self.default_lon = self.default_zoom = None
        self.bounds = None