openlayers/lib/OpenLayers/Control/MousePosition.js

   1 /* Copyright (c) 2006-2008 MetaCarta, Inc., published under the Clear BSD
   2  * license.  See http://svn.openlayers.org/trunk/openlayers/license.txt for the
   3  * full text of the license. */
   4
   5
   6 /**
   7  * @requires OpenLayers/Control.js
   8  */
   9
  10 /**
  11  * Class: OpenLayers.Control.MousePosition
  12  * The MousePosition control displays geographic coordinates of the mouse
  13  * pointer, as it is moved about the map.
  14  *
  15  * Inherits from:
  16  *  - <OpenLayers.Control>
  17  */
  18 OpenLayers.Control.MousePosition = OpenLayers.Class(OpenLayers.Control, {
  19
  20     /**
  21      * Property: element
  22      * {DOMElement}
  23      */
  24     element: null,
  25
  26     /**
  27      * APIProperty: prefix
  28      * {String}
  29      */
  30     prefix: '',
  31
  32     /**
  33      * APIProperty: separator
  34      * {String}
  35      */
  36     separator: ', ',
  37
  38     /**
  39      * APIProperty: suffix
  40      * {String}
  41      */
  42     suffix: '',
  43
  44     /**
  45      * APIProperty: numDigits
  46      * {Integer}
  47      */
  48     numDigits: 5,
  49
  50     /**
  51      * APIProperty: granularity
  52      * {Integer}
  53      */
  54     granularity: 10,
  55
  56     /**
  57      * Property: lastXy
  58      * {<OpenLayers.Pixel>}
  59      */
  60     lastXy: null,
  61
  62     /**
  63      * APIProperty: displayProjection
  64      * {<OpenLayers.Projection>} The projection in which the
  65      * mouse position is displayed
  66      */
  67     displayProjection: null,
  68
  69     /**
  70      * Constructor: OpenLayers.Control.MousePosition
  71      *
  72      * Parameters:
  73      * options - {Object} Options for control.
  74      */
  75     initialize: function(options) {
  76         OpenLayers.Control.prototype.initialize.apply(this, arguments);
  77     },
  78
  79     /**
  80      * Method: destroy
  81      */
  82      destroy: function() {
  83          if (this.map) {
  84              this.map.events.unregister('mousemove', this, this.redraw);
  85          }
  86          OpenLayers.Control.prototype.destroy.apply(this, arguments);
  87      },
  88
  89     /**
  90      * Method: draw
  91      * {DOMElement}
  92      */
  93     draw: function() {
  94         OpenLayers.Control.prototype.draw.apply(this, arguments);
  95
  96         if (!this.element) {
  97             this.div.left = "";
  98             this.div.top = "";
  99             this.element = this.div;
 100         }
 101
 102         this.redraw();
 103         return this.div;
 104     },
 105
 106     /**
 107      * Method: redraw
 108      */
 109     redraw: function(evt) {
 110
 111         var lonLat;
 112
 113         if (evt == null) {
 114             lonLat = new OpenLayers.LonLat(0, 0);
 115         } else {
 116             if (this.lastXy == null ||
 117                 Math.abs(evt.xy.x - this.lastXy.x) > this.granularity ||
 118                 Math.abs(evt.xy.y - this.lastXy.y) > this.granularity)
 119             {
 120                 this.lastXy = evt.xy;
 121                 return;
 122             }
 123
 124             lonLat = this.map.getLonLatFromPixel(evt.xy);
 125             if (!lonLat) {
 126                 // map has not yet been properly initialized
 127                 return;
 128             }
 129             if (this.displayProjection) {
 130                 lonLat.transform(this.map.getProjectionObject(),
 131                                  this.displayProjection );
 132             }
 133             this.lastXy = evt.xy;
 134
 135         }
 136
 137         var newHtml = this.formatOutput(lonLat);
 138
 139         if (newHtml != this.element.innerHTML) {
 140             this.element.innerHTML = newHtml;
 141         }
 142     },
 143
 144     /**
 145      * Method: formatOutput
 146      * Override to provide custom display output
 147      *
 148      * Parameters:
 149      * lonLat - {<OpenLayers.LonLat>} Location to display
 150      */
 151     formatOutput: function(lonLat) {
 152         var digits = parseInt(this.numDigits);
 153         var newHtml =
 154             this.prefix +
 155             lonLat.lon.toFixed(digits) +
 156             this.separator +
 157             lonLat.lat.toFixed(digits) +
 158             this.suffix;
 159         return newHtml;
 160      },
 161
 162     /**
 163      * Method: setMap
 164      */
 165     setMap: function() {
 166         OpenLayers.Control.prototype.setMap.apply(this, arguments);
 167         this.map.events.register( 'mousemove', this, this.redraw);
 168     },
 169
 170     CLASS_NAME: "OpenLayers.Control.MousePosition"
 171 });