canvas_zoom(n) [mojave man page]

canvas::zoom(n) 					      Variations on a canvas						   canvas::zoom(n)

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NAME

       canvas::zoom - Zoom control for canvas::sqmap

SYNOPSIS

       package require Tcl  8.4

       package require Tk  8.4

       package require snit

       package require uevent::onidle

       package require canvas::zoom  ?0.2.1?

       ::canvas::zoom pathName ?options?

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DESCRIPTION

       This package provides a widget to enable the user of a map display to control the zoom level.

API

       ::canvas::zoom pathName ?options?
	      Creates the zoom control widget pathName and configures it. The methods and options supported by the new widget are described in the
	      following sections.

	      The result of the command is pathName.

   OPTIONS
       -orient
	      The value for this option is either vertical, or horizontal, specifying the orientation of the major axis of the widget. The default
	      is vertical.

       -levels
	      The value for this option is a non-negative integer. It specifies the number of zoom levels to support.

       -variable
	      The  value  for  this  option is the name of a global or namespaced variable which is connected with the widget. changes to the zoom
	      level made the widget are propagated to this variable, and in turn changes to the variable are imported into the widget.

       -command
	      This option specifies a command prefix. This callback will be invoked whenever the zoom level is changed.  It  is  called  with  two
	      additional arguments, the zoom control widget, and the new zoom level, in this order.

   METHODS
       The widget supports no methods beyond the standard (configure, cget, etc.).

KEYWORDS

       zoom

canvas								       0.2.1							   canvas::zoom(n)

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

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NAME

       map::slippy - Common code for slippy based map packages

SYNOPSIS

       package require Tcl  8.4

       package require Tk  8.4

       package require map::slippy  ?0.3?

       ::map::slippy length level

       ::map::slippy tiles level

       ::map::slippy tile size

       ::map::slippy tile valid tile levels ?msgvar?

       ::map::slippy geo 2tile geo

       ::map::slippy geo 2point geo

       ::map::slippy tile 2geo tile

       ::map::slippy tile 2point tile

       ::map::slippy point 2geo point

       ::map::slippy point 2tile point

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DESCRIPTION

       This package provides a number of methods doing things needed by all types of slippy-based map packages.

API

       ::map::slippy length level
	      This  method  returns the width/height of a slippy-based map at the specified zoom level, in pixels. This is, in essence, the result
	      of

		   expr { [tiles $level] * [tile size] }

       ::map::slippy tiles level
	      This method returns the width/height of a slippy-based map at the specified zoom level, in tiles.

       ::map::slippy tile size
	      This method returns the width/height of a tile in a slippy-based map, in pixels.

       ::map::slippy tile valid tile levels ?msgvar?
	      This method checks whether tile described a valid tile in a slippy-based map containing that many zoom levels. The result is a bool-
	      ean  value, true if the tile is valid, and false otherwise. For the latter a message is left in the variable named by msgvar, should
	      it be specified.

	      A tile identifier as stored in tile is a list containing zoom level, tile row, and tile column, in this order.  The  command  essen-
	      tially checks this, i.e. the syntax, that the zoom level is between 0 and "levels-1", and that the row/col information is within the
	      boundaries for the zoom level, i.e. 0 ...  "[tiles $zoom]-1".

       ::map::slippy geo 2tile geo
	      Converts a geographical location at a zoom level (geo, a list containing zoom level, latitude, and longitude, in this  order)  to  a
	      tile identifier (list containing zoom level, row, and column) at that level.

       ::map::slippy geo 2point geo
	      Converts	a  geographical  location at a zoom level (geo, a list containing zoom level, latitude, and longitude, in this order) to a
	      pixel position (list containing zoom level, y, and x) at that level.

       ::map::slippy tile 2geo tile
	      Converts a tile identifier at a zoom level (tile, list containing zoom level, row, and column) to a geographical location (list con-
	      taining zoom level, latitude, and longitude, in this order) at that level.

       ::map::slippy tile 2point tile
	      Converts	a tile identifier at a zoom level (tile, a list containing zoom level, row, and column, in this order) to a pixel position
	      (list containing zoom level, y, and x) at that level.

       ::map::slippy point 2geo point
	      Converts a pixel position at a zoom level (point, list containing zoom level, y, and x) to a geographical location (list	containing
	      zoom level, latitude, and longitude, in this order) at that level.

       ::map::slippy point 2tile point
	      Converts	a pixel position at a zoom level (point, a list containing zoom level, y, and x, in this order) to a tile identifier (list
	      containing zoom level, row, and column) at that level.

REFERENCES

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

KEYWORDS

       geodesy, geography, latitute, location, longitude, map, slippy, zoom

map									0.3							    map::slippy(n)