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 | <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>OpenLayers Vector Styles</title> <link rel="stylesheet" href="../theme/default/style.css" type="text/css" /> <link rel="stylesheet" href="style.css" type="text/css" /> <script src="../lib/OpenLayers.js"></script> <script type="text/javascript"> var map; function init(){ map = new OpenLayers.Map('map', {maxResolution:'auto'}); var wms = new OpenLayers.Layer.WMS( "OpenLayers WMS", "http://labs.metacarta.com/wms/vmap0", {layers: 'basic'} ); map.addLayer(wms); map.setCenter(new OpenLayers.LonLat(0, 0), 0); // Strategy 1: Style features based on some attribute. // create 50 random features in the northern hemisphere // give them a "type" attribute that will be used to style // them by size var features = new Array(50); for (var i=0; i<features.length; i++) { features[i] = new OpenLayers.Feature.Vector( new OpenLayers.Geometry.Point( (360 * Math.random()) - 180, 90 * Math.random() ), { type: 5 + parseInt(5 * Math.random()) } ); } // create the layer styleMap with a simple symbolizer template var layer1 = new OpenLayers.Layer.Vector('Points', { styleMap: new OpenLayers.StyleMap({ pointRadius: "${type}", // based on feature.attributes.type fillColor: "#666666" }) }); layer1.addFeatures(features); // Strategy 2: Style features based on something besides attributes. // create 50 random features in the southern hemisphere var features = new Array(50); for (var i=0; i<features.length; i++) { features[i] = new OpenLayers.Feature.Vector( new OpenLayers.Geometry.Point( (360 * Math.random()) - 180, -90 * Math.random() ), { type: 5 + parseInt(5 * Math.random()) } ); } // create the layer styleMap by giving the default style a context var colors = ["red", "green", "blue"]; var context = { getColor: function(feature) { var region = parseInt((feature.geometry.x + 180) / 120); return colors[region]; }, getType: function(feature) { return feature.attributes["type"]; } }; var template = { pointRadius: "${getType}", // using context.getType(feature) fillColor: "${getColor}" // using context.getColor(feature) }; var style = new OpenLayers.Style(template, {context: context}); var layer2 = new OpenLayers.Layer.Vector('Points', { styleMap: new OpenLayers.StyleMap(style) }); layer2.addFeatures(features); map.addLayers([layer1, layer2]); } </script> </head> <body onload="init()"> <h1 id="title">Feature Styles Example</h1> <div id="tags"></div> <p id="shortdesc"> To style features with a custom function that evaluates each feature, use the context option of an OpenLayers.Style object. If the context object contains a function and this function is referenced in a symbolizer, the function will be called with the feature as an argument.. </p> <div id="map" class="smallmap"></div> <div id="docs"> <p>Features in the northern hemisphere are styled according to their "type" attribute. This is accomplished with a simple template that is evaluated with the feature attributes as context.</p> <p>Features in the sourthern hemisphere are styled according to a combination of their attributes and non-attribute properties. This is accomplished using an advanced template that calls functions on the context object passed to the Style constructor.</p> </div> </body> </html> |