Time for action – creating a style function

We'll accomplish this in two steps. First, we'll replace the default style with a simple one, and then, we'll develop a new style to display smaller thumbnails:

First, turn off automatic styling for the KML source by adding extractStyles: false to its options:

var flickrSource = new ol.source.KML({
  url: '../assets/data/flickr_data.kml',
  projection: 'EPSG:3857',
  extractStyles: false
});

Now, create a new function that will generate styles for our photos, we'll use a simple circle style for now:

function flickrStyle(feature) {
  var style = new ol.style.Style({
    image: new ol.style.Circle({
      radius: 6,
      stroke: new ol.style.Stroke({
        color: 'white',
        width: 2
      }),
      fill: new ol.style.Fill({
        color: 'green'
      })
    })
  });
  return [style];
}

That should do it, check out the result in the browser. This is what it looks like with the data saved in the assets folder, yours will look different if you downloaded new data:

What just happened?

Great, we've replaced the automatic style extracted from the KML file with a simple one driven by a style function. Our style function returns an array containing our simple circle style. If you have been paying attention, you should have noticed that our style function is not at all efficient—we are creating a new copy of exactly the same style for every single feature! Don't worry though, this is a temporary state that we'll fix shortly by generating a unique style for each feature, based on its photo and we'll add caching when we do.

Previous Chapter

Styling the features

Next Chapter

Creating a thumbnail style

Table of Contents for OpenLayers 3 : Beginner's Guide

Time for action – creating a style function

What just happened?

Table of Contents for
OpenLayers 3 : Beginner's Guide