5b4174e9db
- added: vtile_backend - fixed: converter now generalizes only intresting ways - first steps to detach renderer
90 lines
No EOL
3.3 KiB
Python
90 lines
No EOL
3.3 KiB
Python
#!/usr/bin/env python
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# -*- coding: utf-8 -*-
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# This file is part of kothic, the realtime map renderer.
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# kothic is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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# kothic is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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# You should have received a copy of the GNU General Public License
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# along with kothic. If not, see <http://www.gnu.org/licenses/>.
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from debug import debug
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from twms import projections
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class Way:
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def __init__(self, type, style, coords):
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self.type = type
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self.coords = coords
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self.style = style
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self.cs = None
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class QuadTileBackend:
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"""
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A class that gives out vector data on demand.
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"""
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def __init__(self,max_zoom = 16,proj = "EPSG:4326", path = "tiles", lang = "ru"):
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debug("Bakend created")
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self.max_zoom = max_zoom # no better tiles available
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self.path = path # path to tile files
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self.lang = lang # map language to use
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self.tiles = {} # loaded vector tiles go here
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self.data_projection = proj # which projection used to cut map in tiles
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self.keep_tiles = 90 # a number of tiles to cache in memory
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self.tile_load_log = [] # used when selecting which tile to unload
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def filename(self, (z,x,y)):
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return "%s/z%s/%s/x%s/%s/y%s.vtile"%(self.path, z, x/1024, x, y/1024, y)
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def load_tile(self, k):
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debug("loading tile: %s"% (k,))
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try:
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f = open(self.filename(k))
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except IOError:
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debug ( "Failed open: %s" % self.filename(k) )
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return {}
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t = {}
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for line in f:
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a = line.split(" ")
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w = Way(a[0], int(a[2]), [float(x) for x in a[3:]])
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t[int(a[1])] = w
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f.close()
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return t
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def collect_garbage(self):
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"""
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Cleans up some RAM by removing least accessed tiles.
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"""
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if len(self.tiles) > self.keep_tiles:
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debug("Now %s tiles cached, trying to kill %s"%(len(self.tiles),len(self.tiles)-self.keep_tiles))
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for tile in self.tile_load_log[0:len(self.tiles)-self.keep_tiles]:
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try:
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del self.tiles[tile]
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self.tile_load_log.remove(tile)
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debug ("killed tile: %s" % (tile,))
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except KeyError, ValueError:
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debug ("tile killed not by us: %s" % (tile,))
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def get_vectors (self, bbox, zoom):
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zoom = min(zoom, self.max_zoom) ## If requested zoom is better than the best, take the best
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zoom = max(zoom, 0) ## Negative zooms are nonsense
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a,d,c,b = [int(x) for x in projections.tile_by_bbox(bbox,zoom, self.data_projection)]
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resp = {}
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for tile in set([(zoom,i,j) for i in range(a, c+1) for j in range(b, d+1)]):
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if tile not in self.tiles:
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self.tiles[tile] = self.load_tile(tile)
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try:
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self.tile_load_log.remove(tile)
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except ValueError:
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pass
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self.tile_load_log.append(tile)
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resp.update(self.tiles[tile])
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self.collect_garbage()
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return resp |