map::slippy::fetcher(3tcl)					 Mapping utilities					map::slippy::fetcher(3tcl)

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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(3tcl)