Страницы справочника OS X

Эта страница руководства для  версии 10.9 Mac OS X

Читать страницы руководства

map::slippy::cache(n)                         Mapping utilities                        map::slippy::cache(n)



____________________________________________________________________________________________________________

NAME
       map::slippy::cache - Management of a tile cache in the local filesystem

SYNOPSIS
       package require Tcl  8.4

       package require Tk  8.4

       package require img::png

       package require map::slippy

       package require map::slippy::cache  ?0.2?

       ::map::slippy::cache cacheName cachedir provider

       cacheName valid tile ?msgvar?

       cacheName exists tile

       cacheName get tile donecmd

____________________________________________________________________________________________________________

DESCRIPTION
       This  package  provides  a  class  for  managing  a cache of tiles for slippy-based maps in the local
       filesystem.

API
       ::map::slippy::cache cacheName cachedir provider
              Creates the cache cacheName and configures it with both the path to  the  directory  contaiing
              the  locally  cached  tiles  (cachedir),  and the command prefix from which it will pull tiles
              asked for and not yet known to the cache itself (provider).

              The result of the command is cacheName.


   METHODS
       cacheName valid tile ?msgvar?
              This method checks the validity of a the given tile identifier.  This is a convenience wrapper
              to ::map::slippy tile valid and has the same interface.

       cacheName exists tile
              This  methods  tests  whether  the  cache  contains the specified tile or not. The result is a
              boolean value, true if the tile is known, and false otherwise. The tile  is  identified  by  a
              list containing three elements, zoom level, row, and column number, in this order.

       cacheName get tile donecmd
              This  is  the  main  method of the cache, retrieving the image for the specified tile from the
              cache. The tile identifier is a list containing three elements, the zoom level, row, and  col-umn column
              umn number of the tile, in this order.

              The  command  refix donecmd will be invoked when the cache either knows the image for the tile
              or that no image will forthcoming.  It will be invoked with either 2 or 3 arguments, i.e.

              [1]    The string set, the tile, and the image.

              [2]    The string unset, and the tile.
       These two possibilities are used to either signal the image for the tile, or that  the  tile  has  no
       image defined for it.

       When the cache has no information about the tile it will invoke the provider command prefix specified
       during its construction, adding three arguments: The string get, the tile, and a  callback  into  the
       cache.  The latter will be invoked by the provider to either transfer the image to the cache, or sig-nal signal
       nal that the tile has no image.

       When multiple requests for the same tile are made only one request will be issued to the provider.


REFERENCES
       [1]    http://wiki.openstreetmap.org/wiki/Main_Page


KEYWORDS
       cache, filesystem, location, map, slippy, tile, zoom



map                                                  0.2                               map::slippy::cache(n)