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diff --git a/misc/openlayers/examples/styles-context.html b/misc/openlayers/examples/styles-context.html new file mode 100644 index 0000000..853e8c3 --- /dev/null +++ b/misc/openlayers/examples/styles-context.html @@ -0,0 +1,117 @@ +<!DOCTYPE html> +<html> + <head> + <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> + <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0"> + <meta name="apple-mobile-web-app-capable" content="yes"> + <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://vmap0.tiles.osgeo.org/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()) + } + ); + } + + // allow testing of specific renderers via "?renderer=Canvas", etc + var renderer = OpenLayers.Util.getParameters(window.location.href).renderer; + renderer = (renderer) ? [renderer] : OpenLayers.Layer.Vector.prototype.renderers; + + // create the layer styleMap with a simple symbolizer template + var layer1 = new OpenLayers.Layer.Vector('Points', { + styleMap: new OpenLayers.StyleMap({ + pointRadius: "${type}", // based on feature.attributes.type + fillColor: "#666666" + }), + renderers: renderer + }); + layer1.addFeatures(features); + + // Strategy 2: Style features based on something besides attributes. + + // create 50 random features in the southern hemisphere + var features = new Array(50); + for (var i=0; i<features.length; i++) { + features[i] = new OpenLayers.Feature.Vector( + new OpenLayers.Geometry.Point( + (360 * Math.random()) - 180, -90 * Math.random() + ), { + type: 5 + parseInt(5 * Math.random()) + } + ); + } + // create the layer styleMap by giving the default style a context + var colors = ["red", "green", "blue"]; + var context = { + getColor: function(feature) { + var region = parseInt((feature.geometry.x + 180) / 120); + return colors[region]; + }, + getSize: function(feature) { + return feature.attributes["type"] / map.getResolution() * .703125; + } + }; + var template = { + pointRadius: "${getSize}", // using context.getSize(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), + renderers: renderer + }); + layer2.addFeatures(features); + + + map.addLayers([layer1, layer2]); + } + </script> + </head> + <body onload="init()"> + <h1 id="title">Feature Styles Example</h1> + + <div id="tags"> + vector, feature, stylemap, light + </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> |