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



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NAME
       map::slippy::fetcher - Accessing a server providing tiles for slippy-
       based maps

SYNOPSIS
       package require Tcl  8.4

       package require Tk  8.4

       package require img::png

       package require map::slippy

       package require map::slippy::fetcher  ?0.2?

       ::map::slippy::fetcher fetcherName levels url

       fetcherName levels

       fetcherName tileheight

       fetcherName tilewidth

       fetcherName get tile donecmd

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DESCRIPTION
       This package provides a class for accessing http servers providing
       tiles for slippy-based maps.

API
       ::map::slippy::fetcher fetcherName levels url
              Creates the fetcher fetcherName and configures it with the
              number of zoom levels supported by the tile server, and the url
              it is listening on for tile requests.

              The result of the command is fetcherName.

   METHODS
       fetcherName levels
              This method returns the number of zoom levels supported by the
              fetcher object, and the tile server it is accessing.

       fetcherName tileheight
              This method returns the height of tiles served, in pixels.

       fetcherName tilewidth
              This method returns the width of tiles served, in pixels.

       fetcherName get tile donecmd
              This is the main method of the fetcher, retrieving the image for
              the specified tile. The tile identifier is a list containing
              three elements, the zoom level, row, and column number of the
              tile, in this order.

              The command refix donecmd will be invoked when the fetcher
              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.

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

KEYWORDS
       http, location, map, server, slippy, tile, url, zoom



map                                   0.2              map::slippy::fetcher(n)
