openlayers/lib/OpenLayers/Handler/Polygon.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/Handler/Path.js
   8  * @requires OpenLayers/Geometry/Polygon.js
   9  */
  10
  11 /**
  12  * Class: OpenLayers.Handler.Polygon
  13  * Handler to draw a polygon on the map.  Polygon is displayed on mouse down,
  14  * moves on mouse move, and is finished on mouse up.
  15  *
  16  * Inherits from:
  17  *  - <OpenLayers.Handler.Path>
  18  *  - <OpenLayers.Handler>
  19  */
  20 OpenLayers.Handler.Polygon = OpenLayers.Class(OpenLayers.Handler.Path, {
  21
  22     /**
  23      * Parameter: polygon
  24      * {<OpenLayers.Feature.Vector>}
  25      */
  26     polygon: null,
  27
  28     /**
  29      * Constructor: OpenLayers.Handler.Polygon
  30      * Create a Polygon Handler.
  31      *
  32      * Parameters:
  33      * control - {<OpenLayers.Control>} The control that owns this handler
  34      * callbacks - {Object} An object with a properties whose values are
  35      *     functions.  Various callbacks described below.
  36      * options - {Object} An optional object with properties to be set on the
  37      *           handler
  38      *
  39      * Named callbacks:
  40      * create - Called when a sketch is first created.  Callback called with
  41      *     the creation point geometry and sketch feature.
  42      * modify - Called with each move of a vertex with the vertex (point)
  43      *     geometry and the sketch feature.
  44      * point - Called as each point is added.  Receives the new point geometry.
  45      * done - Called when the point drawing is finished.  The callback will
  46      *     recieve a single argument, the polygon geometry.
  47      * cancel - Called when the handler is deactivated while drawing.  The
  48      *     cancel callback will receive a geometry.
  49      */
  50     initialize: function(control, callbacks, options) {
  51         OpenLayers.Handler.Path.prototype.initialize.apply(this, arguments);
  52     },
  53
  54     /**
  55      * Method: createFeature
  56      * Add temporary geometries
  57      *
  58      * Parameters:
  59      * pixel - {<OpenLayers.Pixel>} The initial pixel location for the new
  60      *     feature.
  61      */
  62     createFeature: function(pixel) {
  63         var lonlat = this.control.map.getLonLatFromPixel(pixel);
  64         this.point = new OpenLayers.Feature.Vector(
  65             new OpenLayers.Geometry.Point(lonlat.lon, lonlat.lat)
  66         );
  67         this.line = new OpenLayers.Feature.Vector(
  68             new OpenLayers.Geometry.LinearRing([this.point.geometry])
  69         );
  70         this.polygon = new OpenLayers.Feature.Vector(
  71             new OpenLayers.Geometry.Polygon([this.line.geometry])
  72         );
  73         this.callback("create", [this.point.geometry, this.getSketch()]);
  74         this.point.geometry.clearBounds();
  75         this.layer.addFeatures([this.polygon, this.point], {silent: true});
  76     },
  77
  78     /**
  79      * Method: destroyFeature
  80      * Destroy temporary geometries
  81      */
  82     destroyFeature: function() {
  83         OpenLayers.Handler.Path.prototype.destroyFeature.apply(this);
  84         this.polygon = null;
  85     },
  86
  87     /**
  88      * Method: drawFeature
  89      * Render geometries on the temporary layer.
  90      */
  91     drawFeature: function() {
  92         this.layer.drawFeature(this.polygon, this.style);
  93         this.layer.drawFeature(this.point, this.style);
  94     },
  95
  96     /**
  97      * Method: getSketch
  98      * Return the sketch feature.
  99      *
 100      * Returns:
 101      * {<OpenLayers.Feature.Vector>}
 102      */
 103     getSketch: function() {
 104         return this.polygon;
 105     },
 106
 107     /**
 108      * Method: getGeometry
 109      * Return the sketch geometry.  If <multi> is true, this will return
 110      *     a multi-part geometry.
 111      *
 112      * Returns:
 113      * {<OpenLayers.Geometry.Polygon>}
 114      */
 115     getGeometry: function() {
 116         var geometry = this.polygon && this.polygon.geometry;
 117         if(geometry && this.multi) {
 118             geometry = new OpenLayers.Geometry.MultiPolygon([geometry]);
 119         }
 120         return geometry;
 121     },
 122
 123     /**
 124      * Method: dblclick
 125      * Handle double-clicks.  Finish the geometry and send it back
 126      * to the control.
 127      *
 128      * Parameters:
 129      * evt - {Event}
 130      */
 131     dblclick: function(evt) {
 132         if(!this.freehandMode(evt)) {
 133             // remove the penultimate point
 134             var index = this.line.geometry.components.length - 2;
 135             this.line.geometry.removeComponent(this.line.geometry.components[index]);
 136             this.removePoint();
 137             this.finalize();
 138         }
 139         return false;
 140     },
 141
 142     CLASS_NAME: "OpenLayers.Handler.Polygon"
 143 });