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