openlayers/lib/OpenLayers/Control/DragPan.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  * @requires OpenLayers/Handler/Drag.js
   8  */
   9
  10 /**
  11  * Class: OpenLayers.Control.DragPan
  12  * The DragPan control pans the map with a drag of the mouse.
  13  *
  14  * Inherits from:
  15  *  - <OpenLayers.Control>
  16  */
  17 OpenLayers.Control.DragPan = OpenLayers.Class(OpenLayers.Control, {
  18
  19     /**
  20      * Property: type
  21      * {OpenLayers.Control.TYPES}
  22      */
  23     type: OpenLayers.Control.TYPE_TOOL,
  24
  25     /**
  26      * Property: panned
  27      * {Boolean} The map moved.
  28      */
  29     panned: false,
  30
  31     /**
  32      * Property: interval
  33      * {Integer} The number of milliseconds that should ellapse before
  34      *     panning the map again. Set this to increase dragging performance.
  35      *     Defaults to 25 milliseconds.
  36      */
  37     interval: 25,
  38
  39     /**
  40      * Method: draw
  41      * Creates a Drag handler, using <panMap> and
  42      * <panMapDone> as callbacks.
  43      */
  44     draw: function() {
  45         this.handler = new OpenLayers.Handler.Drag(this, {
  46                 "move": this.panMap,
  47                 "done": this.panMapDone
  48             }, {
  49                 interval: this.interval
  50             }
  51         );
  52     },
  53
  54     /**
  55     * Method: panMap
  56     *
  57     * Parameters:
  58     * xy - {<OpenLayers.Pixel>} Pixel of the mouse position
  59     */
  60     panMap: function(xy) {
  61         this.panned = true;
  62         this.map.pan(
  63             this.handler.last.x - xy.x,
  64             this.handler.last.y - xy.y,
  65             {dragging: this.handler.dragging, animate: false}
  66         );
  67     },
  68
  69     /**
  70      * Method: panMapDone
  71      * Finish the panning operation.  Only call setCenter (through <panMap>)
  72      *     if the map has actually been moved.
  73      *
  74      * Parameters:
  75      * xy - {<OpenLayers.Pixel>} Pixel of the mouse position
  76      */
  77     panMapDone: function(xy) {
  78         if(this.panned) {
  79             this.panMap(xy);
  80             this.panned = false;
  81         }
  82     },
  83
  84     CLASS_NAME: "OpenLayers.Control.DragPan"
  85 });