[76] | 1 | /** |
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| 2 | * Copyright (c) 2008-2010 The Open Source Geospatial Foundation |
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| 3 | * |
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| 4 | * Published under the BSD license. |
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| 5 | * See http://svn.geoext.org/core/trunk/geoext/license.txt for the full text |
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| 6 | * of the license. |
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| 7 | */ |
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| 8 | |
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| 9 | /** api: (define) |
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| 10 | * module = GeoExt.data |
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| 11 | * class = ScaleStore |
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| 12 | * base_link = `Ext.data.Store <http://dev.sencha.com/deploy/dev/docs/?class=Ext.data.Store>`_ |
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| 13 | */ |
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| 14 | Ext.namespace("GeoExt.data"); |
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| 15 | |
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| 16 | /** api: constructor |
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| 17 | * .. class:: ScaleStore |
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| 18 | * |
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| 19 | * A store that contains a cache of available zoom levels. The store can |
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| 20 | * optionally be kept synchronized with an ``OpenLayers.Map`` or |
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| 21 | * :class:`GeoExt.MapPanel` object. |
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| 22 | * |
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| 23 | * Records have the following fields: |
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| 24 | * |
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| 25 | * * level - ``Number`` The zoom level. |
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| 26 | * * scale - ``Number`` The scale denominator. |
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| 27 | * * resolution - ``Number`` The map units per pixel. |
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| 28 | */ |
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| 29 | GeoExt.data.ScaleStore = Ext.extend(Ext.data.Store, { |
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| 30 | |
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| 31 | /** api: config[map] |
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| 32 | * ``OpenLayers.Map`` or :class:`GeoExt.MapPanel` |
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| 33 | * Optional map or map panel from which to derive scale values. |
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| 34 | */ |
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| 35 | map: null, |
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| 36 | |
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| 37 | /** private: method[constructor] |
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| 38 | * Construct a ScaleStore from a configuration. The ScaleStore accepts |
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| 39 | * some custom parameters addition to the fields accepted by Ext.Store. |
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| 40 | */ |
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| 41 | constructor: function(config) { |
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| 42 | var map = (config.map instanceof GeoExt.MapPanel ? config.map.map : config.map); |
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| 43 | delete config.map; |
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| 44 | config = Ext.applyIf(config, {reader: new Ext.data.JsonReader({}, [ |
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| 45 | "level", |
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| 46 | "resolution", |
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| 47 | "scale" |
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| 48 | ])}); |
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| 49 | |
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| 50 | GeoExt.data.ScaleStore.superclass.constructor.call(this, config); |
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| 51 | |
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| 52 | if (map) { |
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| 53 | this.bind(map); |
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| 54 | } |
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| 55 | }, |
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| 56 | |
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| 57 | /** api: method[bind] |
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| 58 | * :param map: :class:`GeoExt.MapPanel` or ``OpenLayers.Map`` Panel or map |
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| 59 | * to which we should bind. |
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| 60 | * |
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| 61 | * Bind this store to a map; that is, maintain the zoom list in sync with |
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| 62 | * the map's current configuration. If the map does not currently have a |
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| 63 | * set scale list, then the store will remain empty until the map is |
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| 64 | * configured with one. |
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| 65 | */ |
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| 66 | bind: function(map, options) { |
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| 67 | this.map = (map instanceof GeoExt.MapPanel ? map.map : map); |
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| 68 | this.map.events.register('changebaselayer', this, this.populateFromMap); |
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| 69 | if (this.map.baseLayer) { |
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| 70 | this.populateFromMap(); |
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| 71 | } else { |
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| 72 | this.map.events.register('addlayer', this, this.populateOnAdd); |
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| 73 | } |
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| 74 | }, |
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| 75 | |
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| 76 | /** api: method[unbind] |
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| 77 | * Un-bind this store from the map to which it is currently bound. The |
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| 78 | * currently stored zoom levels will remain, but no further changes from |
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| 79 | * the map will affect it. |
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| 80 | */ |
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| 81 | unbind: function() { |
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| 82 | if (this.map) { |
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| 83 | this.map.events.unregister('addlayer', this, this.populateOnAdd); |
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| 84 | this.map.events.unregister('changebaselayer', this, this.populateFromMap); |
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| 85 | delete this.map; |
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| 86 | } |
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| 87 | }, |
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| 88 | |
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| 89 | /** private: method[populateOnAdd] |
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| 90 | * :param evt: ``Object`` |
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| 91 | * |
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| 92 | * This method handles the case where we have bind() called on a |
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| 93 | * not-fully-configured map so that the zoom levels can be detected when a |
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| 94 | * baselayer is finally added. |
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| 95 | */ |
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| 96 | populateOnAdd: function(evt) { |
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| 97 | if (evt.layer.isBaseLayer) { |
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| 98 | this.populateFromMap(); |
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| 99 | this.map.events.unregister('addlayer', this, this.populateOnAdd); |
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| 100 | } |
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| 101 | }, |
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| 102 | |
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| 103 | /** private: method[populateFromMap] |
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| 104 | * This method actually loads the zoom level information from the |
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| 105 | * OpenLayers.Map and converts it to Ext Records. |
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| 106 | */ |
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| 107 | populateFromMap: function() { |
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| 108 | var zooms = []; |
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| 109 | var resolutions = this.map.baseLayer.resolutions; |
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| 110 | var units = this.map.baseLayer.units; |
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| 111 | |
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| 112 | for (var i=resolutions.length-1; i >= 0; i--) { |
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| 113 | var res = resolutions[i]; |
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| 114 | zooms.push({ |
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| 115 | level: i, |
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| 116 | resolution: res, |
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| 117 | scale: OpenLayers.Util.getScaleFromResolution(res, units) |
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| 118 | }); |
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| 119 | } |
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| 120 | |
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| 121 | this.loadData(zooms); |
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| 122 | }, |
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| 123 | |
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| 124 | /** private: method[destroy] |
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| 125 | */ |
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| 126 | destroy: function() { |
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| 127 | this.unbind(); |
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| 128 | GeoExt.data.ScaleStore.superclass.destroy.apply(this, arguments); |
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| 129 | } |
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| 130 | }); |
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