Combo Chart With MindFusion, a Free JS Chart Library

MindFusion is a charting library that enables you to create and customize the most popular chart types in pure JavaScript. The library is free for commercial use. No attribution is required.

Here, we will take a brief look at the steps you need to take to build this beautiful combo chart from scratch.

You may also like: Database Schema With MindFusion (Part 1).

Setup

It is important to provide an id to the Canvas element, because we will reference it from the JavaScript code.

<canvas id="combiChart" width="400" height="400"></canvas>

We also need to reference the two JavaScript libraries that provide the charting functionality:

<script type="text/javascript" src="Scripts/MindFusion.Common.js"></script>
<script type="text/javascript" src="Scripts/MindFusion.Charting.js"></script>

Then, we'll add a reference to another JavaScript file that will hold the code for the combo chart:

<script type="text/javascript" src="CombiChart.js"></script>

Chart Settings

We create the chart control using a canvas HTML element:

var chartEl = document.getElementById('combiChart');
chartEl.width = chartEl.offsetParent.clientWidth;
chartEl.height = chartEl.offsetParent.clientHeight;
var chart = new Controls.BarChart(chartEl);

We create a bar chart, to which we will add line rendering capabilities. It is also possible to create a line chart and add rendering of bars to it.

Next, we add a title and a grid to the chart:

chart.title = "Corporate Sales";
chart.titleMargin = new Charting.Margins(0, 20, 0, 20);
chart.gridType = GridType.Horizontal;
chart.barSpacingRatio = 1.5;

The barSpacingRatio indicates how much free space will be left between the group of bars relative to the bar width.

Chart Series

We create two serieses for the bars. MindFusion offers a variety of Series types to choose from, and we use two different series for the bars. The first one is a  BarSeries. We use it because it supports setting the X-labels by default:

var labels = new Collections.List([

            "Jan", "Feb", "Mar", "Apr", "May", "Jun",

            "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"

]);

var series1 = new Charting.BarSeries(new Collections.List([2, 4, 6,  8, 10, 12, 14, 16, 18, 20, 22, 24]), null, null, labels);

The other series of type SimpleSeries — it needs two parameters, a list with the necessary data and a list with the appropriate labels:

var series2 = new Charting.SimpleSeries(new Collections.List([1.4, 8, 13, 15, 13, 8, 2, 8, 13, 15, 13, 8]), null);

We don't have labels, so we set them to null. Then, we add the series to a collection:

var series = new Collections.ObservableCollection(new Array(series1, series2));
chart.series = series;

Then, we assign the collection to the series property of the chart. We create the line series as an instance of the Series2D class:

//the line series
var series3 = new Charting.Series2D(new Collections.List([0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]), new Collections.List([1.7, 6, 10.5, 11.5, 11.5, 10, 8, 12, 15.5, 17.5, 17.5, 16]), null);
series3.title = "Average value";
var lseries = new Collections.ObservableCollection(new Array(series3));

After, we add it to another collection.

The chart renders with default bars. We will make it render a line series with the help of a LineRenderer. We create an instance of the LineRenderer class and provide it with the collection of serieses that we want to appear as lines. In our case it is just one:

//add a renderer for the line series
var lRenderer = new Charting.LineRenderer(lseries);
lRenderer.seriesStyle = new Charting.UniformSeriesStyle(lbrush, lstroke, 6);
chart.plot.seriesRenderers.add(lRenderer);

Each chart has a plot, and the plot has a seriesRenderers property that holds all renderers for the chart data. By default, a bar chart has a BarRenderer. Now, we add the LineRenderer to this collection.

Legend

The chart legend is rendered when showLegend is set to true:

//legend settings
chart.showLegend = true;
chart.legendMargin = new Charting.Margins(10, 10, 10, 10);
chart.legendTitle = "Year";

We set the title of the legend to be "Year" and add some margins. The labels of the legend are taken from the title property of each Series. Since the series are rendered by two different renderers, we need to tell the legend which is the renderer, so it can take the labels from both of them and not only from the bar series. This is done with the content property of the legendRenderer:

chart.legendRenderer.content = chart.plot.seriesRenderers; 

Styling

The styling of the Series is done with different Style instances. For the bar chart, we use a PerSeriesStyle instance. It colors all elements of a given series with the respective brush and stroke in the brushes and strokes instances that were provided as parameters:

var firstBrush = new Drawing.Brush("#8898B8");
var secondBrush = new Drawing.Brush("#4E567D");
var firstStroke = new Drawing.Brush("#60759f");
var secondStroke = new Drawing.Brush("#3b415e");

 // assign one brush per series
var brushes = new Collections.List([firstBrush, secondBrush]);
var strokes = new Collections.List([firstStroke, secondStroke]);
chart.plot.seriesStyle = new Charting.PerSeriesStyle(brushes, strokes);

We assign this style to the seriesStyle property of the plot. The line series is colored with an instance of the UniformSeriesStyle class. It applies one brush and one stroke to all elements in all series:

var lbrush = new Drawing.Brush("#F49B96");
var lstroke = new Drawing.Brush("#f07b75");

//add a renderer for the line series
var lRenderer = new Charting.LineRenderer(lseries);
lRenderer.seriesStyle = new Charting.UniformSeriesStyle(lbrush, lstroke, 6);

The third argument indicates stroke thickness. Note, that now we assign the new style to the seriesStyle property of the LineRenderer.

The rest of the settings for the chart appearance are in the theme property:

//theme settings for customizing the chart's appearance
chart.theme.legendBackground = new Drawing.Brush("#f2f2f2");
chart.theme.legendTitleFontSize = 14;
chart.theme.legendBorderStroke = new Drawing.Brush("#cecece");

chart.theme.axisTitleFontSize = 14;
chart.theme.axisLabelsFontSize = 12;

chart.theme.axisTitleFontName = "Verdana";
chart.theme.axisLabelsFontName = "Verdana";
chart.theme.dataLabelsFontName = "Verdana";
chart.theme.dataLabelsFontSize = 12;

chart.theme.gridLineStyle = Drawing.DashStyle.Dash;
chart.theme.gridColor1 = chart.theme.gridColor2 = new Drawing.Color("#ffffff");
chart.theme.gridLineColor = new Drawing.Color("#cecece");

chart.theme.highlightStroke = new Drawing.Brush("#F49B96");
chart.theme.highlightStrokeThickness = 4;

Here, we change the font for the labels and style the legend and the grid. Finally, we customize the stroke that highlights chart elements when the user hovers with the mouse over them.

Summary

We have reached the end of this tutorial. You can download the full source code of the sample with the libraries of Free JS Chart from this link.

You can find out more about MindFusion Free JS Chart library here. 

Further Reading

• The Developer’s Guide to HTML5 Canvas.
• High Performance Data Analytics With Cube.js Pre-Aggregations.
• How to Use MatPlotLib to Display API Performance Data.