openlayers/lib/OpenLayers/Layer/WMS.js

/* Copyright (c) 2006 MetaCarta, Inc., published under the BSD license.
 * See http://svn.openlayers.org/trunk/openlayers/license.txt for the full
 * text of the license. */

/**
 * @class
 * 
 * @requires OpenLayers/Layer/Grid.js
 */
OpenLayers.Layer.WMS = Class.create();
OpenLayers.Layer.WMS.prototype = 
  Object.extend( new OpenLayers.Layer.Grid(), {

    /** Hashtable of default parameter key/value pairs 
     * @final @type Object */
    DEFAULT_PARAMS: { service: "WMS",
                      version: "1.1.1",
                      request: "GetMap",
                      styles: "",
                      exceptions: "application/vnd.ogc.se_inimage",
                      format: "image/jpeg"
                     },

    /** WMS layer by default is a base layer. 
     *   If the user wishes to use a WMS as a datalayer, s/he needs only 
     *   set this property to false.
     * 
     * @type Boolean
     */
    isBaseLayer: true,

    /**
    * @constructor
    *
    * @param {String} name
    * @param {String} url
    * @param {Object} params
    * @param {Object} options Hashtable of extra options to tag onto the layer
    */
    initialize: function(name, url, params, options) {
        var newArguments = new Array();
        if (arguments.length > 0) {
            //uppercase params
            params = OpenLayers.Util.upperCaseObject(params);
            newArguments.push(name, url, params, options);
        }
        OpenLayers.Layer.Grid.prototype.initialize.apply(this, newArguments);

        if (arguments.length > 0) {
            OpenLayers.Util.applyDefaults(
                           this.params, 
                           OpenLayers.Util.upperCaseObject(this.DEFAULT_PARAMS)
                           );
        }
    },    

    /**
     * 
     */
    destroy: function() {
        // for now, nothing special to do here. 
        OpenLayers.Layer.Grid.prototype.destroy.apply(this, arguments);  
    },

    
    /**
     * @param {Object} obj
     * 
     * @returns An exact clone of this OpenLayers.Layer.WMS
     * @type OpenLayers.Layer.WMS
     */
    clone: function (obj) {
        
        if (obj == null) {
            obj = new OpenLayers.Layer.WMS(this.name,
                                           this.url,
                                           this.params,
                                           this.options);
        }

        //get all additions from superclasses
        obj = OpenLayers.Layer.Grid.prototype.clone.apply(this, [obj]);

        // copy/set any non-init, non-simple values here

        return obj;
    },    
    
    /**
     * @param {OpenLayers.Bounds} bounds
     * 
     * @returns A string with the layer's url and parameters and also the 
     *           passed-in bounds and appropriate tile size specified as 
     *           parameters
     * @type String
     */
    getURL: function (bounds) {
        return this.getFullRequestString(
                     {BBOX:bounds.toBBOX(),
                      WIDTH:this.tileSize.w,
                      HEIGHT:this.tileSize.h});
    },

    /**
    * addTile creates a tile, initializes it, and 
    * adds it to the layer div. 
    *
    * @param {OpenLayers.Bounds} bounds
    *
    * @returns The added OpenLayers.Tile.Image
    * @type OpenLayers.Tile.Image
    */
    addTile:function(bounds,position) {
        url = this.getURL(bounds);
        return new OpenLayers.Tile.Image(this, position, bounds, 
                                             url, this.tileSize);
    },

    /**
     * Catch changeParams and uppercase the new params to be merged in
     *  before calling changeParams on the super class.
     * 
     * Once params have been changed, we will need to re-init our tiles
     * 
     * @param {Object} params Hashtable of new params to use
     */
    mergeNewParams:function(params) {
        var upperParams = OpenLayers.Util.upperCaseObject(params);
        var newArguments = [upperParams];
        OpenLayers.Layer.Grid.prototype.mergeNewParams.apply(this, newArguments);

        if (this.map != null) {
            this._initTiles();
        }
    },

    /** combine the layer's url with its params and these newParams. 
    *   
    *    Add the SRS parameter from getProjection() -- this is probably
    *     more eloquently done via a setProjection() method, but this 
    *     works for now and always.
    * 
    * @param {Object} newParams
    * 
    * @type String
    */
    getFullRequestString:function(newParams) {
        var projection = this.map.getProjection();
        this.params.SRS = (projection == "none") ? null : projection;

        return OpenLayers.Layer.Grid.prototype.getFullRequestString.apply(
                                                    this, arguments);
    },
    
    /** @final @type String */
    CLASS_NAME: "OpenLayers.Layer.WMS"
});