k-chart (pie) with aggregates

HTML

<script src="http://cdn.kendostatic.com/2012.1.322/js/kendo.all.min.js"></script>
<link rel="stylesheet" href="http://cdn.kendostatic.com/2012.1.322/styles/kendo.common.min.css">
<link rel="stylesheet" href="http://cdn.kendostatic.com/2012.1.322/styles/kendo.dataviz.min.css">
<div id="chart"></div>

JavaScript

var pictures = [
    { type: "JPG", size: 2 },
    { type: "JPG", size: 2 },
    { type: "JPG", size: 2 },
    { type: "JPG", size: 2 },
    { type: "JPG", size: 2 },
    { type: "JPG", size: 2 },
    { type: "JPG", size: 2 },
    { type: "JPG", size: 2 },
    { type: "JPG", size: 2 },
    { type: "JPG", size: 2 },
    { type: "JPG", size: 2 },
    { type: "JPG", size: 2 },
    { type: "JPG", size: 2 },
    { type: "JPG", size: 2 },
    { type: "JPG", size: 2 },
    { type: "PNG", size: 3 }, 
    { type: "PNG", size: 3 }, 
    { type: "PNG", size: 3 }, 
    { type: "PNG", size: 3 }, 
    { type: "PNG", size: 3 }, 
    { type: "PNG", size: 3 }, 
    { type: "PNG", size: 3 }, 
    { type: "PNG", size: 3 }, 
    { type: "PNG", size: 3 }, 
    { type: "PNG", size: 3 }, 
    { type: "PNG", size: 3 }, 
    { type: "PNG", size: 3 }
];

var dataSource = new kendo.data.DataSource({
    data: pictures,
    //create group and aggregates
    group: {
        field: "type",
        aggregates: [
            { field: "size", aggregate: "sum" }
        ]
    }
});
//read dataSource to load the data
dataSource.read();

var series = [],
    categories = [],
    items = dataSource.view(),
    length = items.length,
    item;
//create the chart series  
for (var i = 0; i < length; i++) {
    item = items[i];
    series.push(item.aggregates.size.sum);
    categories.push(item.value);
}
//initialize the chart
$(document).ready(function() {
    $("#chart").kendoChart({
        dataSource: dataSource,
        seriesDefaults: {
            type: "bar"
        },
        series: [{name: "size", data: series}],
        categoryAxis: {
            categories: categories
        },
        tooltip: {
            visible: true
        }
    });
});