| /* Copyright (c) 2006-2010 by OpenLayers Contributors (see authors.txt for | |
| * full list of contributors). Published under the Clear BSD license. | |
| * See http://svn.openlayers.org/trunk/openlayers/license.txt for the | |
| * full text of the license. */ | |
| /** | |
| * @requires OpenLayers/Util.js | |
| */ | |
| /** | |
| * Class: OpenLayers.Projection | |
| * Class for coordinate transforms between coordinate systems. | |
| * Depends on the proj4js library. If proj4js is not available, | |
| * then this is just an empty stub. | |
| */ | |
| OpenLayers.Projection = OpenLayers.Class({ | |
| /** | |
| * Property: proj | |
| * {Object} Proj4js.Proj instance. | |
| */ | |
| proj: null, | |
| /** | |
| * Property: projCode | |
| * {String} | |
| */ | |
| projCode: null, | |
| /** | |
| * Constructor: OpenLayers.Projection | |
| * This class offers several methods for interacting with a wrapped | |
| * pro4js projection object. | |
| * | |
| * Parameters: | |
| * projCode - {String} A string identifying the Well Known Identifier for | |
| * the projection. | |
| * options - {Object} An optional object to set additional properties | |
| * on the layer. | |
| * | |
| * Returns: | |
| * {<OpenLayers.Projection>} A projection object. | |
| */ | |
| initialize: function(projCode, options) { | |
| OpenLayers.Util.extend(this, options); | |
| this.projCode = projCode; | |
| if (window.Proj4js) { | |
| this.proj = new Proj4js.Proj(projCode); | |
| } | |
| }, | |
| /** | |
| * APIMethod: getCode | |
| * Get the string SRS code. | |
| * | |
| * Returns: | |
| * {String} The SRS code. | |
| */ | |
| getCode: function() { | |
| return this.proj ? this.proj.srsCode : this.projCode; | |
| }, | |
| /** | |
| * APIMethod: getUnits | |
| * Get the units string for the projection -- returns null if | |
| * proj4js is not available. | |
| * | |
| * Returns: | |
| * {String} The units abbreviation. | |
| */ | |
| getUnits: function() { | |
| return this.proj ? this.proj.units : null; | |
| }, | |
| /** | |
| * Method: toString | |
| * Convert projection to string (getCode wrapper). | |
| * | |
| * Returns: | |
| * {String} The projection code. | |
| */ | |
| toString: function() { | |
| return this.getCode(); | |
| }, | |
| /** | |
| * Method: equals | |
| * Test equality of two projection instances. Determines equality based | |
| * soley on the projection code. | |
| * | |
| * Returns: | |
| * {Boolean} The two projections are equivalent. | |
| */ | |
| equals: function(projection) { | |
| if (projection && projection.getCode) { | |
| return this.getCode() == projection.getCode(); | |
| } else { | |
| return false; | |
| } | |
| }, | |
| /* Method: destroy | |
| * Destroy projection object. | |
| */ | |
| destroy: function() { | |
| delete this.proj; | |
| delete this.projCode; | |
| }, | |
| CLASS_NAME: "OpenLayers.Projection" | |
| }); | |
| /** | |
| * Property: transforms | |
| * Transforms is an object, with from properties, each of which may | |
| * have a to property. This allows you to define projections without | |
| * requiring support for proj4js to be included. | |
| * | |
| * This object has keys which correspond to a 'source' projection object. The | |
| * keys should be strings, corresponding to the projection.getCode() value. | |
| * Each source projection object should have a set of destination projection | |
| * keys included in the object. | |
| * | |
| * Each value in the destination object should be a transformation function, | |
| * where the function is expected to be passed an object with a .x and a .y | |
| * property. The function should return the object, with the .x and .y | |
| * transformed according to the transformation function. | |
| * | |
| * Note - Properties on this object should not be set directly. To add a | |
| * transform method to this object, use the <addTransform> method. For an | |
| * example of usage, see the OpenLayers.Layer.SphericalMercator file. | |
| */ | |
| OpenLayers.Projection.transforms = {}; | |
| /** | |
| * APIMethod: addTransform | |
| * Set a custom transform method between two projections. Use this method in | |
| * cases where the proj4js lib is not available or where custom projections | |
| * need to be handled. | |
| * | |
| * Parameters: | |
| * from - {String} The code for the source projection | |
| * to - {String} the code for the destination projection | |
| * method - {Function} A function that takes a point as an argument and | |
| * transforms that point from the source to the destination projection | |
| * in place. The original point should be modified. | |
| */ | |
| OpenLayers.Projection.addTransform = function(from, to, method) { | |
| if(!OpenLayers.Projection.transforms[from]) { | |
| OpenLayers.Projection.transforms[from] = {}; | |
| } | |
| OpenLayers.Projection.transforms[from][to] = method; | |
| }; | |
| /** | |
| * APIMethod: transform | |
| * Transform a point coordinate from one projection to another. Note that | |
| * the input point is transformed in place. | |
| * | |
| * Parameters: | |
| * point - {{OpenLayers.Geometry.Point> | Object} An object with x and y | |
| * properties representing coordinates in those dimensions. | |
| * sourceProj - {OpenLayers.Projection} Source map coordinate system | |
| * destProj - {OpenLayers.Projection} Destination map coordinate system | |
| * | |
| * Returns: | |
| * point - {object} A transformed coordinate. The original point is modified. | |
| */ | |
| OpenLayers.Projection.transform = function(point, source, dest) { | |
| if (source.proj && dest.proj) { | |
| point = Proj4js.transform(source.proj, dest.proj, point); | |
| } else if (source && dest && | |
| OpenLayers.Projection.transforms[source.getCode()] && | |
| OpenLayers.Projection.transforms[source.getCode()][dest.getCode()]) { | |
| OpenLayers.Projection.transforms[source.getCode()][dest.getCode()](point); | |
| } | |
| return point; | |
| }; | |