Files
openlayers/lib/OpenLayers/Geometry/Polygon.js

62 lines
2.0 KiB
JavaScript

/* Copyright (c) 2006-2007 MetaCarta, Inc., published under a modified BSD license.
* See http://svn.openlayers.org/trunk/openlayers/repository-license.txt
* for the full text of the license. */
/**
* @requires OpenLayers/Geometry/Collection.js
*
* Class: OpenLayers.Geometry.Polygon
* Polygon is a collection of Geometry.LinearRings.
*
* Inherits from:
* - <OpenLayers.Geometry.Collection>
* - <OpenLayers.Geometry>
*/
OpenLayers.Geometry.Polygon = OpenLayers.Class(
OpenLayers.Geometry.Collection, {
/**
* Property: componentTypes
* {Array(String)} An array of class names representing the types of
* components that the collection can include. A null value means the
* component types are not restricted.
*/
componentTypes: ["OpenLayers.Geometry.LinearRing"],
/**
* Constructor: OpenLayers.Geometry.Polygon
* Constructor for a Polygon geometry.
* The first ring (this.component[0])is the outer bounds of the polygon and
* all subsequent rings (this.component[1-n]) are internal holes.
*
*
* Parameters:
* components - Array({<OpenLayers.Geometry.LinearRing>})
*/
initialize: function(components) {
OpenLayers.Geometry.Collection.prototype.initialize.apply(this,
arguments);
},
/**
* APIMethod: getArea
* Calculated by subtracting the areas of the internal holes from the
* area of the outer hole.
*
* Returns:
* {float} The area of the geometry
*/
getArea: function() {
var area = 0.0;
if ( this.components && (this.components.length > 0)) {
area += Math.abs(this.components[0].getArea());
for (var i = 1; i < this.components.length; i++) {
area -= Math.abs(this.components[i].getArea());
}
}
return area;
},
CLASS_NAME: "OpenLayers.Geometry.Polygon"
});