[OpenLayers-Trac] [OpenLayers] #1548: add support for a context in StyleMap.addUniqueValueRules

[OpenLayers]

#1548: add support for a context in StyleMap.addUniqueValueRules
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  Reporter:  pgiraud  |       Owner:     
      Type:  feature  |      Status:  new
  Priority:  minor    |   Milestone:     
 Component:  general  |     Version:  2.6
Resolution:           |    Keywords:     
     State:           |  
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Comment (by ahocevar):

 Actually, this is not a problem of the StyleMap.addUniqueValueRules
 method, but of the Rule class in general, because it's context property is
 static.

 An efficient solution would be a modified getContext method in Rule.js:
 {{{
     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;
     },
 }}}

 With that, the use case could be fulfilled with a slightly modified
 addUniqueValueRules method in StyleMap.js:
 {{{
     addUniqueValueRules: function(renderIntent, property, symbolizers,
             context) {
         var rules = [];
         for (var value in symbolizers) {
             rules.push(new OpenLayers.Rule({
                 symbolizer: symbolizers[value],
                 context: context,
                 filter: new OpenLayers.Filter.Comparison({
                     type: OpenLayers.Filter.Comparison.EQUAL_TO,
                     property: property,
                     value: value
                 })
             }));
         }
         this.styles[renderIntent].addRules(rules);
     },
 }}}

 To achieve what Pierre wants, his application code would just have to look
 like the following:
 {{{
 var context = function(feature) {
     return feature;
 }

 var lookup = {
     "Insert": {fillColor: "green"},
     "Delete": {fillColor: "red"}
 }

 styleMap.addUniqueValueRules("default", "state", lookup, context);
 }}}

 Although the usage of this Rule context is different than the one of the
 Style context, this way of doing it feels more intuitive to me.

-- 
Ticket URL: <http://trac.openlayers.org/ticket/1548#comment:1>
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