7ac845503f
git-svn-id: http://svn.openlayers.org/tags/openlayers/release-2.5-rc5@4831 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf
90 lines
3.0 KiB
JavaScript
90 lines
3.0 KiB
JavaScript
/* Copyright (c) 2006-2007 MetaCarta, Inc., published under the BSD license.
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* See http://svn.openlayers.org/trunk/openlayers/release-license.txt
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* for the full text of the license. */
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/**
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* @requires OpenLayers/Geometry/Collection.js
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*
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* Class: OpenLayers.Geometry.Polygon
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* Polygon is a collection of Geometry.LinearRings.
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*
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* Inherits from:
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* - <OpenLayers.Geometry.Collection>
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* - <OpenLayers.Geometry>
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*/
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OpenLayers.Geometry.Polygon = OpenLayers.Class(
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OpenLayers.Geometry.Collection, {
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/**
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* Property: componentTypes
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* {Array(String)} An array of class names representing the types of
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* components that the collection can include. A null value means the
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* component types are not restricted.
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*/
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componentTypes: ["OpenLayers.Geometry.LinearRing"],
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/**
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* Constructor: OpenLayers.Geometry.Polygon
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* Constructor for a Polygon geometry.
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* The first ring (this.component[0])is the outer bounds of the polygon and
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* all subsequent rings (this.component[1-n]) are internal holes.
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*
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*
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* Parameters:
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* components - Array({<OpenLayers.Geometry.LinearRing>})
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*/
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initialize: function(components) {
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OpenLayers.Geometry.Collection.prototype.initialize.apply(this,
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arguments);
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},
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/**
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* APIMethod: getArea
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* Calculated by subtracting the areas of the internal holes from the
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* area of the outer hole.
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*
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* Returns:
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* {float} The area of the geometry
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*/
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getArea: function() {
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var area = 0.0;
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if ( this.components && (this.components.length > 0)) {
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area += Math.abs(this.components[0].getArea());
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for (var i = 1; i < this.components.length; i++) {
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area -= Math.abs(this.components[i].getArea());
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}
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}
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return area;
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},
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CLASS_NAME: "OpenLayers.Geometry.Polygon"
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});
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/**
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* APIMethod: createRegularPolygon
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* Create a regular polygon around a radius. Useful for creating circles
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* and the like.
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*
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* Parameters:
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* origin - {<OpenLayers.Geometry.Point>} center of polygon.
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* radius - {Float} distance to vertex, in map units.
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* sides - {Integer} Number of sides. 20 approximates a circle.
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* rotation - {Float} original angle of rotation, in degrees.
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*/
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OpenLayers.Geometry.Polygon.createRegularPolygon = function(origin, radius, sides, rotation) {
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var angle = Math.PI * ((1/sides) - (1/2));
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if(rotation) {
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angle += (rotation / 180) * Math.PI;
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}
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var rotateAngle, x, y;
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var points = [];
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for(var i=0; i<sides; ++i) {
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rotatedAngle = angle + (i * 2 * Math.PI / sides);
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x = origin.x + (radius * Math.cos(rotatedAngle));
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y = origin.y + (radius * Math.sin(rotatedAngle));
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points.push(new OpenLayers.Geometry.Point(x, y));
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}
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var ring = new OpenLayers.Geometry.LinearRing(points);
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return new OpenLayers.Geometry.Polygon([ring]);
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}
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