openlayers/lib/OpenLayers/Control/ZoomBox.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/Box.js
   8  */
   9
  10 /**
  11  * Class: OpenLayers.Control.ZoomBox
  12  * The ZoomBox control enables zooming directly to a given extent, by drawing
  13  * a box on the map. The box is drawn by holding down shift, whilst dragging
  14  * the mouse.
  15  *
  16  * Inherits from:
  17  *  - <OpenLayers.Control>
  18  */
  19 OpenLayers.Control.ZoomBox = OpenLayers.Class(OpenLayers.Control, {
  20     /**
  21      * Property: type
  22      * {OpenLayers.Control.TYPE}
  23      */
  24     type: OpenLayers.Control.TYPE_TOOL,
  25
  26     /**
  27      * Property: out
  28      * {Boolean} Should the control be used for zooming out?
  29      */
  30     out: false,
  31
  32     /**
  33      * Property: alwaysZoom
  34      * {Boolean} Always zoom in/out, when box drawed
  35      */
  36     alwaysZoom: false,
  37
  38     /**
  39      * Method: draw
  40      */
  41     draw: function() {
  42         this.handler = new OpenLayers.Handler.Box( this,
  43                             {done: this.zoomBox}, {keyMask: this.keyMask} );
  44     },
  45
  46     /**
  47      * Method: zoomBox
  48      *
  49      * Parameters:
  50      * position - {<OpenLayers.Bounds>} or {<OpenLayers.Pixel>}
  51      */
  52     zoomBox: function (position) {
  53         if (position instanceof OpenLayers.Bounds) {
  54             if (!this.out) {
  55                 var minXY = this.map.getLonLatFromPixel(
  56                             new OpenLayers.Pixel(position.left, position.bottom));
  57                 var maxXY = this.map.getLonLatFromPixel(
  58                             new OpenLayers.Pixel(position.right, position.top));
  59                 var bounds = new OpenLayers.Bounds(minXY.lon, minXY.lat,
  60                                                maxXY.lon, maxXY.lat);
  61             } else {
  62                 var pixWidth = Math.abs(position.right-position.left);
  63                 var pixHeight = Math.abs(position.top-position.bottom);
  64                 var zoomFactor = Math.min((this.map.size.h / pixHeight),
  65                     (this.map.size.w / pixWidth));
  66                 var extent = this.map.getExtent();
  67                 var center = this.map.getLonLatFromPixel(
  68                     position.getCenterPixel());
  69                 var xmin = center.lon - (extent.getWidth()/2)*zoomFactor;
  70                 var xmax = center.lon + (extent.getWidth()/2)*zoomFactor;
  71                 var ymin = center.lat - (extent.getHeight()/2)*zoomFactor;
  72                 var ymax = center.lat + (extent.getHeight()/2)*zoomFactor;
  73                 var bounds = new OpenLayers.Bounds(xmin, ymin, xmax, ymax);
  74             }
  75             // always zoom in/out
  76             var lastZoom = this.map.getZoom();
  77             this.map.zoomToExtent(bounds);
  78             if (lastZoom == this.map.getZoom() && this.alwaysZoom == true){
  79                 this.map.zoomTo(lastZoom + (this.out ? -1 : 1));
  80             }
  81         } else { // it's a pixel
  82             if (!this.out) {
  83                 this.map.setCenter(this.map.getLonLatFromPixel(position),
  84                                this.map.getZoom() + 1);
  85             } else {
  86                 this.map.setCenter(this.map.getLonLatFromPixel(position),
  87                                this.map.getZoom() - 1);
  88             }
  89         }
  90     },
  91
  92     CLASS_NAME: "OpenLayers.Control.ZoomBox"
  93 });