57161a94be
git-svn-id: http://svn.openlayers.org/trunk/openlayers@1383 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf
442 lines
13 KiB
JavaScript
442 lines
13 KiB
JavaScript
/* Copyright (c) 2006 MetaCarta, Inc., published under the BSD license.
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* See http://svn.openlayers.org/trunk/openlayers/license.txt for the full
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* text of the license. */
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/**
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* @class
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*/
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OpenLayers.Layer = Class.create();
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OpenLayers.Layer.prototype = {
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/** @type String */
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id: null,
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/** @type String */
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name: null,
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/** @type DOMElement */
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div: null,
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/** This variable is set when the layer is added to the map, via the
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* accessor function setMap()
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*
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* @type OpenLayers.Map */
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map: null,
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/** Whether or not the layer is a base layer. This should be set
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* individually by all subclasses.
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* Default is false
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*
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* @type Boolean
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*/
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isBaseLayer: false,
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/** asserts whether or not the layer's images have an alpha channel
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*
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* @type boolean */
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alpha: false,
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// OPTIONS
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/** @type Array */
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options: null,
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/** @type String */
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projection: null,
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/** @type String */
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units: null,
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/** @type Array */
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scales: null,
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/** @type Array */
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resolutions: null,
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/** @type OpenLayers.Bounds */
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maxExtent: null,
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/** @type OpenLayers.Bounds */
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minExtent: null,
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/** @type float */
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maxResolution: null,
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/** @type float */
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minResolution: null,
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/** @type int */
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numZoomLevels: null,
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/** @type float */
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minScale: null,
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/** @type float */
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maxScale: null,
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/**
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* @constructor
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*
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* @param {String} name
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* @param {Object} options Hashtable of extra options to tag onto the layer
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*/
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initialize: function(name, options) {
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if (arguments.length > 0) {
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//store a copy of the custom options for later cloning
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this.options = Object.extend(new Object(), options);
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//add options to layer
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Object.extend(this, this.options);
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this.name = name;
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//generate unique id based on name
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this.id = OpenLayers.Util.createUniqueID("Layer_");
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if (this.div == null) {
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this.div = OpenLayers.Util.createDiv();
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this.div.style.width = "100%";
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this.div.style.height = "100%";
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}
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}
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},
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/**
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* Destroy is a destructor: this is to alleviate cyclic references which
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* the Javascript garbage cleaner can not take care of on its own.
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*/
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destroy: function() {
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if (this.map != null) {
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this.map.removeLayer(this);
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}
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this.map = null;
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this.name = null;
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this.div = null;
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this.options = null;
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},
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/**
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* @returns An exact clone of this OpenLayers.Layer
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* @type OpenLayers.Layer
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*/
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clone: function (obj) {
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if (obj == null) {
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obj = new OpenLayers.Layer(this.name, this.options);
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}
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// catch any randomly tagged-on properties
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OpenLayers.Util.applyDefaults(obj, this);
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// a cloned layer should never have its map property set
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// because it has not been added to a map yet.
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obj.map = null;
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return obj;
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},
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/**
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* @param {String} newName
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*/
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setName: function(newName) {
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this.name = newName;
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if (this.map != null)
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this.map.events.triggerEvent("changelayer");
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},
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/**
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* @param {Object} newOptions
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*/
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addOptions: function (newOptions) {
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// update our copy for clone
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Object.extend(this.options, newOptions);
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// add new options to this
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Object.extend(this, this.options);
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},
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/**
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*
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*/
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onMapResize: function() {
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//this function can be implemented by subclasses
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},
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/**
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* @param {OpenLayers.Bounds} bound
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* @param {Boolean} zoomChanged tells when zoom has changed, as layers
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* have to do some init work in that case.
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* @param {Boolean} minor
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*/
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moveTo:function(bounds, zoomChanged, minor) {
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//this function can be implemented by subclasses.
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},
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/** Set the map property for the layer. This is done through an accessor
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* so that subclasses can override this and take special action once
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* they have their map variable set.
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*
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* Here we take care to bring over any of the necessary default properties
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* from the map.
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*
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* @param {OpenLayers.Map} map
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*/
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setMap: function(map) {
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this.map = map;
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var properties = new Array(
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'projection', 'units',
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'scales', 'resolutions',
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'maxScale', 'minScale',
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'maxResolution', 'minResolution',
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'minExtent', 'maxExtent',
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'numZoomLevels'
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);
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if (this.map.maxZoomLevel && !this.numZoomLevels) {
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this.numZoomLevels = this.map.maxZoomLevel + 1;
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}
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for(var i=0; i < properties.length; i++) {
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if (this[properties[i]] == null) {
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this[properties[i]] = this.map[properties[i]];
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}
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}
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if (this.isBaseLayer) {
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this.initResolutions();
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}
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},
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/**
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* @returns Whether or not the layer is visible
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* @type Boolean
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*/
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getVisibility: function() {
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return (this.div.style.display != "none");
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},
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/**
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* @param {Boolean} visible
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* @param {Boolean} noEvent
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*/
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setVisibility: function(visible, noEvent) {
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if (visible != this.getVisibility()) {
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this.div.style.display = (visible) ? "block" : "none";
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if ((visible) && (this.map != null)) {
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var extent = this.map.getExtent();
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if (extent != null) {
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this.moveTo(this.map.getExtent());
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}
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}
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if ((this.map != null) &&
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((noEvent == null) || (noEvent == false))) {
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this.map.events.triggerEvent("changelayer");
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}
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}
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},
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/**
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* @param {Boolean} isBaseLayer
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*/
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setIsBaseLayer: function(isBaseLayer) {
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this.isBaseLayer = isBaseLayer;
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if (this.map != null) {
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this.map.events.triggerEvent("changelayer");
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}
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},
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/********************************************************/
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/* */
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/* Baselayer Functions */
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/* */
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/********************************************************/
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/** This method's responsibility is to set up the 'resolutions' array
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* for the layer -- this array is what the layer will use to interface
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* between the zoom levels of the map and the resolution display of the
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* layer.
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*
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* The user has several options that determine how the array is set up.
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*
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* For a detailed explanation, see the following wiki from the
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* openlayers.org homepage:
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*
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* http://trac.openlayers.org/wiki/SettingZoomLevels
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*
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* @private
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*/
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initResolutions: function() {
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if ((this.scales != null) || (this.resolutions != null)) {
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//preset levels
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if (this.scales != null) {
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this.resolutions = new Array();
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for(var i = 0; i < this.scales.length; i++) {
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this.resolutions[i] =
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OpenLayers.Util.getResolutionFromScale(this.scales[i],
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this.units);
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}
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}
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this.numZoomLevels = this.resolutions.length;
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} else {
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//maxResolution and numZoomLevels
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this.resolutions = new Array();
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// determine maxResolution
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if (this.minScale) {
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this.maxResolution =
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OpenLayers.Util.getResolutionFromScale(this.minScale,
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this.units);
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} else if (this.maxResolution == "auto") {
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var viewSize = this.map.getSize();
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var wRes = this.maxExtent.getWidth() / viewSize.w;
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var hRes = this.maxExtent.getHeight()/ viewSize.h;
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this.maxResolution = Math.max(wRes, hRes);
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}
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// determine minResolution
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if (this.maxScale != null) {
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this.minResolution =
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OpenLayers.Util.getResolutionFromScale(this.maxScale);
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} else if ((this.minResolution == "auto") &&
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(this.minExtent != null)){
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var viewSize = this.map.getSize();
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var wRes = this.minExtent.getWidth() / viewSize.w;
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var hRes = this.minExtent.getHeight()/ viewSize.h;
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this.minResolution = Math.max(wRes, hRes);
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}
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// determine numZoomLevels
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if (this.minResolution != null) {
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var ratio = this.maxResolution / this.minResolution;
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this.numZoomLevels =
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Math.floor(Math.log(ratio) / Math.log(2)) + 1;
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}
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// now we have numZoomLevels and maxResolution,
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// we can populate the resolutions array
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for (var i=0; i < this.numZoomLevels; i++) {
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this.resolutions.push(this.maxResolution / Math.pow(2, i));
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}
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}
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},
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/**
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* @returns The currently selected resolution of the map, taken from the
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* resolutions array, indexed by current zoom level.
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* @type float
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*/
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getResolution: function() {
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var zoom = this.map.getZoom();
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return this.resolutions[zoom];
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},
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/** Calculates based on resolution, center, and mapsize
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*
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* @param {float} resolution Specific resolution to get an extent for.
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* If null, this.getResolution() is called
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* @returns A Bounds object which represents the lon/lat bounds of the
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* current viewPort.
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* @type OpenLayers.Bounds
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*/
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getExtent: function(resolution) {
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var extent = null;
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var center = this.map.getCenter();
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if (center != null) {
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if (resolution == null) {
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resolution = this.getResolution();
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}
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var size = this.map.getSize();
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var w_deg = size.w * resolution;
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var h_deg = size.h * resolution;
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extent = new OpenLayers.Bounds(center.lon - w_deg / 2,
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center.lat - h_deg / 2,
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center.lon + w_deg / 2,
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center.lat + h_deg / 2);
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}
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return extent;
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},
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/**
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* @param {OpenLayers.Bounds} bounds
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*
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* @returns The index of the zoomLevel (entry in the resolutions array)
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* that still contains the passed-in extent. We do this by
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* calculating the ideal resolution for the given exteng (based
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* on the map size) and then find the smallest resolution that
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* is greater than this ideal resolution.
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* @type int
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*/
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getZoomForExtent: function(extent) {
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var viewSize = this.map.getSize();
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var idealResolution = Math.max( extent.getWidth() / viewSize.w,
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extent.getHeight() / viewSize.h );
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return this.getZoomForResolution(idealResolution);
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},
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/**
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* @param {float} resolution
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*
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* @returns The index of the zoomLevel (entry in the resolutions array)
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* that is the smallest resolution that is greater than the
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* passed-in resolution.
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* @type int
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*/
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getZoomForResolution: function(resolution) {
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for(var i=1; i <= this.resolutions.length; i++) {
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if ( this.resolutions[i] < resolution) {
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break;
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}
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}
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return (i - 1);
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},
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/**
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* @param {OpenLayers.Pixel} viewPortPx
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*
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* @returns An OpenLayers.LonLat which is the passed-in view port
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* OpenLayers.Pixel, translated into lon/lat by the layer
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* @type OpenLayers.LonLat
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*/
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getLonLatFromViewPortPx: function (viewPortPx) {
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var size = this.map.getSize();
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var center = this.map.getCenter();
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var res = this.map.getResolution();
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var delta_x = viewPortPx.x - (size.w / 2);
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var delta_y = viewPortPx.y - (size.h / 2);
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return new OpenLayers.LonLat(center.lon + delta_x * res ,
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center.lat - delta_y * res);
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},
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/**
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* @param {OpenLayers.LonLat} lonlat
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*
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* @returns An OpenLayers.Pixel which is the passed-in OpenLayers.LonLat,
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* translated into view port pixels
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* @type OpenLayers.Pixel
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*/
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getViewPortPxFromLonLat: function (lonlat) {
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var resolution = this.map.getResolution();
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var extent = this.map.getExtent();
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return new OpenLayers.Pixel(
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Math.round(1/resolution * (lonlat.lon - extent.left)),
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Math.round(1/resolution * (extent.top - lonlat.lat))
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);
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},
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/** @final @type String */
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CLASS_NAME: "OpenLayers.Layer"
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};
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