openlayers/lib/OpenLayers/Control/Attribution.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  * @requires OpenLayers/Control.js
   7  */
   8
   9 /**
  10  * Class: OpenLayers.Control.Attribution
  11  * The attribution control adds attribution from layers to the map display.
  12  * It uses 'attribution' property of each layer.
  13  *
  14  * Inherits from:
  15  *  - <OpenLayers.Control>
  16  */
  17 OpenLayers.Control.Attribution =
  18   OpenLayers.Class(OpenLayers.Control, {
  19
  20     /**
  21      * APIProperty: seperator
  22      * {String} String used to seperate layers.
  23      */
  24     separator: ", ",
  25
  26     /**
  27      * Constructor: OpenLayers.Control.Attribution
  28      *
  29      * Parameters:
  30      * options - {Object} Options for control.
  31      */
  32     initialize: function(options) {
  33         OpenLayers.Control.prototype.initialize.apply(this, arguments);
  34     },
  35
  36     /**
  37      * Method: destroy
  38      * Destroy control.
  39      */
  40     destroy: function() {
  41         this.map.events.un({
  42             "removelayer": this.updateAttribution,
  43             "addlayer": this.updateAttribution,
  44             "changelayer": this.updateAttribution,
  45             "changebaselayer": this.updateAttribution,
  46             scope: this
  47         });
  48
  49         OpenLayers.Control.prototype.destroy.apply(this, arguments);
  50     },
  51
  52     /**
  53      * Method: draw
  54      * Initialize control.
  55      *
  56      * Returns:
  57      * {DOMElement} A reference to the DIV DOMElement containing the control
  58      */
  59     draw: function() {
  60         OpenLayers.Control.prototype.draw.apply(this, arguments);
  61
  62         this.map.events.on({
  63             'changebaselayer': this.updateAttribution,
  64             'changelayer': this.updateAttribution,
  65             'addlayer': this.updateAttribution,
  66             'removelayer': this.updateAttribution,
  67             scope: this
  68         });
  69         this.updateAttribution();
  70
  71         return this.div;
  72     },
  73
  74     /**
  75      * Method: updateAttribution
  76      * Update attribution string.
  77      */
  78     updateAttribution: function() {
  79         var attributions = [];
  80         if (this.map && this.map.layers) {
  81             for(var i=0, len=this.map.layers.length; i<len; i++) {
  82                 var layer = this.map.layers[i];
  83                 if (layer.attribution && layer.getVisibility()) {
  84                     attributions.push( layer.attribution );
  85                 }
  86             }
  87             this.div.innerHTML = attributions.join(this.separator);
  88         }
  89     },
  90
  91     CLASS_NAME: "OpenLayers.Control.Attribution"
  92 });