122 lines
3.5 KiB
Python
122 lines
3.5 KiB
Python
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# coding=utf-8
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"""
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MBTiles provider for MapView
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============================
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This provider is based on .mbfiles from MapBox.
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See: http://mbtiles.org/
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"""
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__all__ = ["MBTilesMapSource"]
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import io
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import sqlite3
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import threading
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from kivy.core.image import Image as CoreImage
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from kivy.core.image import ImageLoader
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from mapview.downloader import Downloader
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from mapview.source import MapSource
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class MBTilesMapSource(MapSource):
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def __init__(self, filename, **kwargs):
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super().__init__(**kwargs)
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self.filename = filename
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self.db = sqlite3.connect(filename)
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# read metadata
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c = self.db.cursor()
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metadata = dict(c.execute("SELECT * FROM metadata"))
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if metadata["format"] == "pbf":
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raise ValueError("Only raster maps are supported, not vector maps.")
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self.min_zoom = int(metadata["minzoom"])
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self.max_zoom = int(metadata["maxzoom"])
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self.attribution = metadata.get("attribution", "")
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self.bounds = bounds = None
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cx = cy = 0.0
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cz = 5
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if "bounds" in metadata:
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self.bounds = bounds = tuple(map(float, metadata["bounds"].split(",")))
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if "center" in metadata:
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cx, cy, cz = tuple(map(float, metadata["center"].split(",")))
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elif self.bounds:
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cx = (bounds[2] + bounds[0]) / 2.0
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cy = (bounds[3] + bounds[1]) / 2.0
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cz = self.min_zoom
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self.default_lon = cx
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self.default_lat = cy
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self.default_zoom = int(cz)
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self.projection = metadata.get("projection", "")
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self.is_xy = self.projection == "xy"
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def fill_tile(self, tile):
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if tile.state == "done":
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return
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Downloader.instance(self.cache_dir).submit(self._load_tile, tile)
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def _load_tile(self, tile):
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# global db context cannot be shared across threads.
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ctx = threading.local()
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if not hasattr(ctx, "db"):
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ctx.db = sqlite3.connect(self.filename)
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# get the right tile
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c = ctx.db.cursor()
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c.execute(
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(
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"SELECT tile_data FROM tiles WHERE "
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"zoom_level=? AND tile_column=? AND tile_row=?"
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),
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(tile.zoom, tile.tile_x, tile.tile_y),
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)
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row = c.fetchone()
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if not row:
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tile.state = "done"
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return
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# no-file loading
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try:
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data = io.BytesIO(row[0])
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except Exception:
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# android issue, "buffer" does not have the buffer interface
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# ie row[0] buffer is not compatible with BytesIO on Android??
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data = io.BytesIO(bytes(row[0]))
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im = CoreImage(
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data,
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ext='png',
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filename="{}.{}.{}.png".format(tile.zoom, tile.tile_x, tile.tile_y),
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)
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if im is None:
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tile.state = "done"
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return
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return self._load_tile_done, (tile, im,)
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def _load_tile_done(self, tile, im):
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tile.texture = im.texture
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tile.state = "need-animation"
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def get_x(self, zoom, lon):
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if self.is_xy:
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return lon
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return super().get_x(zoom, lon)
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def get_y(self, zoom, lat):
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if self.is_xy:
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return lat
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return super().get_y(zoom, lat)
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def get_lon(self, zoom, x):
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if self.is_xy:
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return x
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return super().get_lon(zoom, x)
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def get_lat(self, zoom, y):
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if self.is_xy:
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return y
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return super().get_lat(zoom, y)
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