[76] | 1 | /* Copyright (c) 2006-2010 by OpenLayers Contributors (see authors.txt for |
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| 2 | * full list of contributors). Published under the Clear BSD license. |
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| 3 | * See http://svn.openlayers.org/trunk/openlayers/license.txt for the |
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| 4 | * full text of the license. */ |
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| 5 | |
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| 6 | |
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| 7 | /** |
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| 8 | * @requires OpenLayers/Util.js |
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| 9 | * @requires OpenLayers/Style.js |
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| 10 | * @requires OpenLayers/Symbolizer/Point.js |
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| 11 | * @requires OpenLayers/Symbolizer/Line.js |
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| 12 | * @requires OpenLayers/Symbolizer/Polygon.js |
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| 13 | * @requires OpenLayers/Symbolizer/Text.js |
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| 14 | * @requires OpenLayers/Symbolizer/Raster.js |
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| 15 | */ |
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| 16 | |
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| 17 | /** |
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| 18 | * Class: OpenLayers.Rule |
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| 19 | * This class represents an SLD Rule, as being used for rule-based SLD styling. |
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| 20 | */ |
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| 21 | OpenLayers.Rule = OpenLayers.Class({ |
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| 22 | |
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| 23 | /** |
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| 24 | * Property: id |
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| 25 | * {String} A unique id for this session. |
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| 26 | */ |
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| 27 | id: null, |
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| 28 | |
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| 29 | /** |
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| 30 | * APIProperty: name |
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| 31 | * {String} name of this rule |
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| 32 | */ |
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| 33 | name: null, |
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| 34 | |
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| 35 | /** |
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| 36 | * Property: title |
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| 37 | * {String} Title of this rule (set if included in SLD) |
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| 38 | */ |
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| 39 | title: null, |
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| 40 | |
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| 41 | /** |
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| 42 | * Property: description |
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| 43 | * {String} Description of this rule (set if abstract is included in SLD) |
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| 44 | */ |
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| 45 | description: null, |
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| 46 | |
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| 47 | /** |
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| 48 | * Property: context |
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| 49 | * {Object} An optional object with properties that the rule should be |
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| 50 | * evaluated against. If no context is specified, feature.attributes will |
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| 51 | * be used. |
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| 52 | */ |
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| 53 | context: null, |
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| 54 | |
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| 55 | /** |
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| 56 | * Property: filter |
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| 57 | * {<OpenLayers.Filter>} Optional filter for the rule. |
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| 58 | */ |
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| 59 | filter: null, |
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| 60 | |
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| 61 | /** |
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| 62 | * Property: elseFilter |
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| 63 | * {Boolean} Determines whether this rule is only to be applied only if |
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| 64 | * no other rules match (ElseFilter according to the SLD specification). |
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| 65 | * Default is false. For instances of OpenLayers.Rule, if elseFilter is |
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| 66 | * false, the rule will always apply. For subclasses, the else property is |
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| 67 | * ignored. |
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| 68 | */ |
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| 69 | elseFilter: false, |
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| 70 | |
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| 71 | /** |
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| 72 | * Property: symbolizer |
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| 73 | * {Object} Symbolizer or hash of symbolizers for this rule. If hash of |
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| 74 | * symbolizers, keys are one or more of ["Point", "Line", "Polygon"]. The |
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| 75 | * latter if useful if it is required to style e.g. vertices of a line |
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| 76 | * with a point symbolizer. Note, however, that this is not implemented |
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| 77 | * yet in OpenLayers, but it is the way how symbolizers are defined in |
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| 78 | * SLD. |
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| 79 | */ |
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| 80 | symbolizer: null, |
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| 81 | |
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| 82 | /** |
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| 83 | * Property: symbolizers |
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| 84 | * {Array} Collection of symbolizers associated with this rule. If |
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| 85 | * provided at construction, the symbolizers array has precedence |
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| 86 | * over the deprecated symbolizer property. Note that multiple |
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| 87 | * symbolizers are not currently supported by the vector renderers. |
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| 88 | * Rules with multiple symbolizers are currently only useful for |
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| 89 | * maintaining elements in an SLD document. |
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| 90 | */ |
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| 91 | symbolizers: null, |
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| 92 | |
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| 93 | /** |
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| 94 | * APIProperty: minScaleDenominator |
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| 95 | * {Number} or {String} minimum scale at which to draw the feature. |
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| 96 | * In the case of a String, this can be a combination of text and |
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| 97 | * propertyNames in the form "literal ${propertyName}" |
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| 98 | */ |
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| 99 | minScaleDenominator: null, |
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| 100 | |
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| 101 | /** |
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| 102 | * APIProperty: maxScaleDenominator |
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| 103 | * {Number} or {String} maximum scale at which to draw the feature. |
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| 104 | * In the case of a String, this can be a combination of text and |
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| 105 | * propertyNames in the form "literal ${propertyName}" |
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| 106 | */ |
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| 107 | maxScaleDenominator: null, |
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| 108 | |
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| 109 | /** |
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| 110 | * Constructor: OpenLayers.Rule |
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| 111 | * Creates a Rule. |
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| 112 | * |
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| 113 | * Parameters: |
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| 114 | * options - {Object} An optional object with properties to set on the |
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| 115 | * rule |
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| 116 | * |
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| 117 | * Returns: |
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| 118 | * {<OpenLayers.Rule>} |
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| 119 | */ |
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| 120 | initialize: function(options) { |
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| 121 | this.symbolizer = {}; |
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| 122 | OpenLayers.Util.extend(this, options); |
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| 123 | if (this.symbolizers) { |
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| 124 | delete this.symbolizer; |
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| 125 | } |
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| 126 | this.id = OpenLayers.Util.createUniqueID(this.CLASS_NAME + "_"); |
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| 127 | }, |
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| 128 | |
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| 129 | /** |
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| 130 | * APIMethod: destroy |
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| 131 | * nullify references to prevent circular references and memory leaks |
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| 132 | */ |
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| 133 | destroy: function() { |
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| 134 | for (var i in this.symbolizer) { |
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| 135 | this.symbolizer[i] = null; |
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| 136 | } |
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| 137 | this.symbolizer = null; |
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| 138 | delete this.symbolizers; |
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| 139 | }, |
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| 140 | |
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| 141 | /** |
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| 142 | * APIMethod: evaluate |
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| 143 | * evaluates this rule for a specific feature |
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| 144 | * |
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| 145 | * Parameters: |
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| 146 | * feature - {<OpenLayers.Feature>} feature to apply the rule to. |
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| 147 | * |
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| 148 | * Returns: |
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| 149 | * {Boolean} true if the rule applies, false if it does not. |
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| 150 | * This rule is the default rule and always returns true. |
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| 151 | */ |
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| 152 | evaluate: function(feature) { |
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| 153 | var context = this.getContext(feature); |
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| 154 | var applies = true; |
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| 155 | |
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| 156 | if (this.minScaleDenominator || this.maxScaleDenominator) { |
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| 157 | var scale = feature.layer.map.getScale(); |
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| 158 | } |
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| 159 | |
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| 160 | // check if within minScale/maxScale bounds |
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| 161 | if (this.minScaleDenominator) { |
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| 162 | applies = scale >= OpenLayers.Style.createLiteral( |
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| 163 | this.minScaleDenominator, context); |
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| 164 | } |
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| 165 | if (applies && this.maxScaleDenominator) { |
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| 166 | applies = scale < OpenLayers.Style.createLiteral( |
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| 167 | this.maxScaleDenominator, context); |
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| 168 | } |
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| 169 | |
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| 170 | // check if optional filter applies |
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| 171 | if(applies && this.filter) { |
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| 172 | // feature id filters get the feature, others get the context |
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| 173 | if(this.filter.CLASS_NAME == "OpenLayers.Filter.FeatureId") { |
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| 174 | applies = this.filter.evaluate(feature); |
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| 175 | } else { |
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| 176 | applies = this.filter.evaluate(context); |
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| 177 | } |
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| 178 | } |
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| 179 | |
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| 180 | return applies; |
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| 181 | }, |
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| 182 | |
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| 183 | /** |
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| 184 | * Method: getContext |
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| 185 | * Gets the context for evaluating this rule |
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| 186 | * |
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| 187 | * Paramters: |
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| 188 | * feature - {<OpenLayers.Feature>} feature to take the context from if |
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| 189 | * none is specified. |
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| 190 | */ |
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| 191 | getContext: function(feature) { |
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| 192 | var context = this.context; |
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| 193 | if (!context) { |
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| 194 | context = feature.attributes || feature.data; |
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| 195 | } |
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| 196 | if (typeof this.context == "function") { |
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| 197 | context = this.context(feature); |
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| 198 | } |
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| 199 | return context; |
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| 200 | }, |
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| 201 | |
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| 202 | /** |
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| 203 | * APIMethod: clone |
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| 204 | * Clones this rule. |
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| 205 | * |
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| 206 | * Returns: |
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| 207 | * {<OpenLayers.Rule>} Clone of this rule. |
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| 208 | */ |
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| 209 | clone: function() { |
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| 210 | var options = OpenLayers.Util.extend({}, this); |
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| 211 | if (this.symbolizers) { |
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| 212 | // clone symbolizers |
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| 213 | var len = this.symbolizers.length; |
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| 214 | options.symbolizers = new Array(len); |
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| 215 | for (var i=0; i<len; ++i) { |
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| 216 | options.symbolizers[i] = this.symbolizers[i].clone(); |
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| 217 | } |
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| 218 | } else { |
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| 219 | // clone symbolizer |
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| 220 | options.symbolizer = {}; |
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| 221 | var value, type; |
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| 222 | for(var key in this.symbolizer) { |
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| 223 | value = this.symbolizer[key]; |
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| 224 | type = typeof value; |
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| 225 | if(type === "object") { |
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| 226 | options.symbolizer[key] = OpenLayers.Util.extend({}, value); |
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| 227 | } else if(type === "string") { |
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| 228 | options.symbolizer[key] = value; |
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| 229 | } |
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| 230 | } |
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| 231 | } |
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| 232 | // clone filter |
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| 233 | options.filter = this.filter && this.filter.clone(); |
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| 234 | // clone context |
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| 235 | options.context = this.context && OpenLayers.Util.extend({}, this.context); |
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| 236 | return new OpenLayers.Rule(options); |
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| 237 | }, |
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| 238 | |
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| 239 | CLASS_NAME: "OpenLayers.Rule" |
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| 240 | }); |
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