JavaScript Diagram with Chart Nodes

In this blog post we will create DiagramNode instances that render a chart. The charts get resized according to the size of the node. We will use two MindFusion libraries for JavaScript – Charting and Diagramming. You can run the sample online from this link:

I. Project Setup

We will use a web page that will hold the HTML Canvas element that we need in order to render the diagram:

<div style="width: 100%; height: 100%; overflow: scroll;">
    <canvas id="diagram" width="2100" height="2100" style="background:#f0f0f0;">
        This page requires a browser that supports HTML 5 Canvas element.
    </canvas>
</div>

We give the diagram’s Canavs big width and height and we also provide an id. The id is important because we will need to access the Canvas from code.

We add the scripts that we need in order to use the Charting and Diagramming libraries:

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

We add the references at the end of the web page, just before the closing BODY tag. We also need to add a reference to a JavaScript file that will hold the code for our sample. We name it “PieNode.js”.

II. The Diagram

In the code-behind file we create a diagram instance. We use the DOMContentLoaded event to initialize our diagram:

document.addEventListener("DOMContentLoaded", function ()
{
// create a Diagram component that wraps the "diagram" canvas
diagram = MindFusion.Diagramming.Diagram.create(document.getElementById("diagram"));
diagram.setBehavior(MindFusion.Diagramming.Behavior.LinkShapes);
diagram.setLinkHeadShapeSize(2);
diagram.setBounds(new Rect(0, 0, 2000, 2000));

// draw a pie when the user creates a node
diagram.addEventListener(Events.nodeCreated, onNodeCreated);

});

The Behavior enumeration lists various modes of behavior for the diagram. We choose Behavior.LinkShapes, which creates nodes, when the mouse is dragged
over an empty area and connects the nodes if the mouse is dragged from an existing node. We set tbe bounds of the diagram to a big Rect which guarantees that the user can draw nodes anywhere on the visible area. When the user draws towards the edge of the browser, the diagram control expands automatically.

Finally, we add an event handler for the nodeCreated event.

//nodeCreated event handler
function onNodeCreated(sender, args)
{
	var node = args.getNode();
	
	var nBounds = node.getBounds ();
	var topLeftCoord = diagram.docToClient(nBounds.topLeft());
	var bottomRightCoord = diagram.docToClient(nBounds.bottomRight());
	.......................................................
}

At first we get the node that was created. Then we need to get its actual size, for which we use the docToClient method that converts between diagram and browser measure units. We get the two coordinates of the node’s bounding rectangle.

We create then a Canvas, which takes the size of the node’s rectangle:

............................................
.....................................................
var pieChartCanvas = document.createElement('canvas');
pieChartCanvas.width = bottomRightCoord.x - topLeftCoord.x;
pieChartCanvas.height = bottomRightCoord.y - topLeftCoord.y;

We then add this temp canvas to the body of the web page and call a method “createPie” where we draw the pie chart. Once the chart is drawn we get the URL of the image and set is to the node with the setImageLocation method. We remove the Canvas from the tree with the elements because we want to use for the next node.

//create a temporary Canvas for the pie chart
//to draw itself upon
document.body.appendChild(pieChartCanvas);
createPie(pieChartCanvas);
var pieImageLocation = pieChartCanvas.toDataURL();
node.setImageLocation(pieImageLocation);
document.body.removeChild(pieChartCanvas);

III. The Chart

We create a pie chart in the Canvas provided to the createPie method:

//draw a pie chart on the provided canvas
function createPie(pieChartCanvas)
{
	var pieChart = new Controls.PieChart(pieChartCanvas);
	pieChart.startAngle = 45;			
	pieChart.showLegend = false;
	pieChart.title = "Sales";
	pieChart.titleMargin = new Charting.Margins(0, 10, 0, 0);
	pieChart.chartPadding = 3;
...........................

We set some appearance properties to make the chart look the way we want – change the start angle of the pie, add a title and title margin, hide the legend. Then we create a PieSeries which holds the data and the labels of the pie. We assign the PieSeries to the series property of the pie chart:

// create sample data
var values = new Collections.List([20.00, 30.00, 15.00, 40.00]);
pieChart.series = new Charting.PieSeries(
	values,
	new Collections.List(["20", "30", "15", "40"]),
null);

We style the chart with an instance of the PerElementSeriesStyle class, which colors all elements of a Series with the consequtive Brush and stroke from its brushes and strokes collections. Then we adjust the dataLabelsFontSize to match the size of the canvas. We make the labels be drawn with a white brush using the dataLabelsBrush property. Finally we call draw to render the pie.

var brushes = new Collections.List(
		[
			new Drawing.Brush("#0455BF"),
			new Drawing.Brush("#033E8C"),
			new Drawing.Brush("#F24405"),
			new Drawing.Brush("#F21905")
		]);

	var seriesBrushes = new Collections.List();
	seriesBrushes.add(brushes);

	var strokes = new Collections.List(
		[
			new Drawing.Brush("#c0c0c0")
		]);

	var seriesStrokes = new Collections.List();
	seriesStrokes.add(strokes);

	pieChart.plot.seriesStyle = new Charting.PerElementSeriesStyle(seriesBrushes, seriesStrokes);
	pieChart.theme.highlightStroke = new Drawing.Brush("#000063");
	pieChart.theme.dataLabelsFontSize = pieChartCanvas.height/20;
	pieChart.theme.dataLabelsBrush = new Drawing.Brush("#FFFFFF");

	pieChart.draw();

And with that the sample is ready. You can download the source code together with all MindFusion JavaScript libraries used from:

http://mindfusion.eu/samples/javascript/diagram/PieNodes.zip

About Diagramming for JavaScript: This native JavaScript library provides developers with the ability to create and customize any type of diagram, decision tree, flowchart, class hierarchy, graph, genealogy tree and more. The control offers rich event set, numerous customization options, animations, graph operations, styling and themes. You have more than 100 predefined nodes, table nodes and more than 15 automatic layout algorithms. Learn more about Diagramming for JavaScript at https://mindfusion.eu/javascript-diagram.html.

About Charting for JavaScript: MindFusion library for interactive charts and gauges. It supports all common chart types including 3D bar charts. Charts can have a grid, a legend, unlimited number of axes and series. Scroll, zoom and pan are supported out of the box. You can easily create your own chart series by implementing the Series interface.
The gauges library is part of Charting for JavaScript. It supports oval and linear gauge with several types of labels and ticks. Various samples show you how the implement the gauges to create and customize all popular gauge types: car dashboard, clock, thermometer, compass etc. Learn more about Charting and Gauges for JavaScript at https://mindfusion.eu/javascript-chart.html.

Horizontal Full Bar Chart in JavaScript

We use here MindFusion JavaScript library for Charts and Gauges to build this horizontal stacked bar chart that renders custom tooltips:

Run the sample from this link.

You can download the source code together with the libraries used from the link at the bottom of the post.

I. General Setup

We split our chart in two files – one is the web page that hosts an HTML Canvas element that will render the chart. The other file is a JavaScript code-behind file that contains the code for the chart.

We need to add reference to two JavaScript library files that provide the charting and drawing functionality that we need:

MindFusion.Common.js
MindFusion.Charting.js

We place them in a Scripts folder at the same level as our web page and JavaScript code behind file.

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

We also add a reference to the code-behind file that we call StackedBarChart.js:

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

Now we need to create an HTML Canvas element and we must provide it with an id so we can reference it in our JS code:

<canvas id="barChart" width="600px" height="400px"></canvas>

The size of the Canvas determines the size of the chart.

II. Chart Instance and General Settings

We add some namespace mappings that allow us to reference classes from the Chart library in a more consice manner:

var Charting = MindFusion.Charting;
var Controls = MindFusion.Charting.Controls;
var Collections = MindFusion.Charting.Collections;
var Drawing = MindFusion.Charting.Drawing;
var GridType = MindFusion.Charting.GridType;
var ToolTip = Charting.ToolTip;

Then we create an instance of the BarChart control. We need to get the Dom Element that corresponds to the Canvas that we’ve prepared for the chart:

var chartEl = document.getElementById('barChart');
chartEl.width = chartEl.offsetParent.clientWidth;
chartEl.height = chartEl.offsetParent.clientHeight;
var chart = new Controls.BarChart(chartEl, Charting.BarLayout.Stack);

The BarChart constructor supports a second argument that indicates the type of the bar chart to render.

We set the bar chart to horizontal with the horizontalBars property. We also make the bars thicker than normal – the property for this is barSpacingRatio It measures the thickness of the bars as a percente of the bar width.

chart.horizontalBars = true;
chart.barSpacingRatio = 0.2;

III. The Data Series

We want our chart to render labels as tooltips, inside the bars and also we want custom labels at the Y-axis. The predefined BarSeries class accepts 4 lists with data: one for bar data and three with labels inside the bars, at the top of the bars and at the X-axis. So, it is not an exact match for what we want to do and we need to customize it.

We will create our own custom BarSeries that we will call SeriesWithLabels. We will inherit the BarSeries class and override its constructor and getLabel members to provide the desired data for the desired type of labels.

We override the constructor by creating three new variables, which receive the data for the bars and the labels:

var SeriesWithLabels = function (barValues, innerLabels, yLabels) {
    Charting.BarSeries.apply(this, [barValues, innerLabels, yLabels]);
	
	this.yLabels = yLabels;
	this.innerLabels = innerLabels;
	this.values = barValues;
    
};

SeriesWithLabels.prototype = Object.create(Charting.BarSeries.prototype);

Note that before we do anything else in the new constructor we need to call the apply method of the BarSeries class to transfer the provided data to the base class. We also need to create a prototype of the new series and also define its constructor:

 Object.defineProperty(SeriesWithLabels.prototype, 'constructor', {
   	value: SeriesWithLabels,
   	enumerable: false,
   	writable: true
   });

Next we will override the getLabel method. This is the method that returns the correct label according to the requested label kind and the index of the label. We said we want to support inner labels, tooltips and Y-axis labels. So, we make sure our implementation of getLabel returns exactly those labels:

SeriesWithLabels.prototype.getLabel = function (index, kind) {
    if ((kind & Charting.LabelKinds.YAxisLabel) != 0 && this.yLabels)
        return this.yLabels.items()[index];

    if ((kind & Charting.LabelKinds.InnerLabel) != 0 && this.innerLabels)
        return this.innerLabels.items()[index];
	
	if ((kind & Charting.LabelKinds.ToolTip) != 0)
        return getPercentLabel(index, this);
   
    return "";
};

Getting the correct inner and top label is easy – we just return the label at the requested position. What is more work is building the tooltip. We want our tooltip to calculate the portion of the part in the stacked bar the mouse currently is over, to the entire bar. This means we need to calculate the data of all bar portions, which is a combination of the values at the requested position in all three bar series. We do this calculation in a separate method called getPercentLabel.

Before we get to the getPercentLabel method let’s create 3 instances of our custom SeriesWithLabels class:

var labels = new Collections.List([
	"POSITION", "SALARY", "LOCATION", "COLLEAGUES", "WORKTIME"
]);

// create sample data series
var series1 = new SeriesWithLabels(new Collections.List([123, 212, 220, 115, 0.01]), new Collections.List([123, 212, 220, 115, 0]), labels);
var series2 = new SeriesWithLabels(new Collections.List([53, 132, 42, 105, 80]), new Collections.List([53, 132, 42, 105, 80]), null);
var series3 = new SeriesWithLabels(new Collections.List([224, 56, 138, 180, 320]), new Collections.List([224, 56, 138, 180, 320]), null);

The third argument in the SeriesWithLabels constructor is the lists with labels at the Y-axis. We need just one list with labels and we set it with the first series. The other series take null as their third argument.

We need to create a collection with the series and assign it to the series property of the chart:

var series = new Collections.ObservableCollection(new Array(series1, series2, series3));
chart.series = series;

There is a special property called supportedLabels that is member of Series and tells the chart, what type of labels this Series needs to draw. In our case we need to indicate that the first series renders labels at the Y-axis, the inner labels and tooltips. The other two series render inner labels and tooltips:

series1.supportedLabels = Charting.LabelKinds.YAxisLabel | Charting.LabelKinds.InnerLabel | Charting.LabelKinds.ToolTip;
series2.supportedLabels = Charting.LabelKinds.InnerLabel | Charting.LabelKinds.ToolTip;
series3.supportedLabels = Charting.LabelKinds.InnerLabel | Charting.LabelKinds.ToolTip;

Now let’s get back to the method that calculates the tooltip:

function getPercentLabel(index, series)
{
	var value1 = series1.values.items()[index];
	var value2 = series2.values.items()[index];
	var value3 = series3.values.items()[index];
	
	var theValue = series.values.items()[index];	
	var result = theValue/(value1+value2+value3) * 100;
	
	return Number(result).toFixed(0) + "%";	
};

In it we calculate the sum of all data that is rendered by the stacked bar at the specified index. Then we convert the data to percent and format it to have no numbers after the decimal point. That gives us a little inacurracy sometimes, when the value gets rounded to the next number and the sum of all percents actually is 101. You might want to change the formatting to toFixed(2) if you want to see the exact number rendered.

IV. Axes and Tooltip

By default the X-axis shows a title and both axes render the auto scale for the data of the chart. We need to hide the scale and we also hide the ticks that are rendered at the interval values:

chart.xAxis.title = "";
chart.yAxis.title = "";
chart.showXCoordinates = false;
chart.showYCoordinates = false;
chart.showXTicks = false;
chart.showYTicks = false;

We don’t want our chart to render axes at all, so we will draw them with the color of the chart background. You can also draw them with a transparent brush:

chart.theme.axisStroke = new Drawing.Brush(Drawing.Color.knownColors.White);

The tooltip renders automatically when the user hovers a bar. We can customize it with the properties of the static Tooltip class:

ToolTip.brush = new Drawing.Brush("#fafafa");
ToolTip.pen = new Drawing.Pen("#9caac6");
ToolTip.textBrush = new Drawing.Brush("#5050c0");
ToolTip.horizontalPadding = 6;
ToolTip.verticalPadding = 4;
ToolTip.horizontalOffset = 76;
ToolTip.verticalOffset = 34;
ToolTip.font = new Charting.Drawing.Font("Verdana", 12);

We add some padding to the tooltip text and increase its font size. We also render the tooltip with a little offset that will place it inside the bar, ater the inner label.

V. Styling and Legend

Styling o the charts is done through instances of SeriesStyle derived classes. The instance is assigned to the seriesStyle property of the Chart In our case we want to color each bar in three sections. That means the portion of the bar that corresponds to the same series is colored in the same color for all its members. That kind of styling is supported by the PerSeriesStyle class. It accepts a list with brushes and strokes and paints all elements of the series corresponding to the index of the brush in the list with this brush:

// create bar brushes
var thirdBrush = new Drawing.Brush("#97b5b5");
var secondBrush = new Drawing.Brush("#5a79a5");
var firstBrush = new Drawing.Brush("#003466");

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

The theme property is the main property for styling the chart. The Theme class exposes fields for customizing the appearance of all chart elements. We first adjust the font and size of the axis labels – remember we have labels only at the Y-axis:

chart.theme.axisTitleFontSize = 14;
chart.theme.axisLabelsFontSize = 11;
chart.theme.axisTitleFontName = "Verdana";
chart.theme.axisLabelsFontName = "Verdana";
chart.theme.axisLabelsFontSize = 14;
chart.theme.axisStroke = new Drawing.Brush(Drawing.Color.knownColors.White);

The labels inside the bars are called data labels and there are dataLabels*** properties that regulate their appearance:

chart.theme.dataLabelsFontName = "Verdana";
chart.theme.dataLabelsFontSize = 14;
chart.theme.dataLabelsBrush = new Drawing.Brush("#ffffff");

The dataLabelsBrush is also used when the legend labels are rendered. In order to make them visible we need to set a darker background for the legend:

chart.theme.legendBackground = new Drawing.Brush("#cccccc");
chart.theme.legendBorderStroke = new Drawing.Brush("#cecece");

The labels inside the legend are taken from the title property of the Series instances:

series.item(0).title = "CAREER START";
series.item(1).title = "MIDDLE OF CAREER";
series.item(2).title = "CAREER END";

Finally we should not forget to call the draw method that actually renders the chart:

chart.draw();

With this our costimization of the chart is done. You can download the source code of the sample and the MindFusion JavaScript libraries used from this link:

Download the Horizontal Stacked Bar Chart Sample: Source Code and Libraries

About Charting for JavaScript: MindFusion library for interactive charts and gauges. It supports all common chart types including 3D bar charts. Charts can have a grid, a legend, unlimitd number of axes and series. Scroll, zoom and pan are supported out of the box. You can easily create your own chart series by implementing the Series interface.
The gauges library is part of Charting for JavaScript. It supports oval and linear gauge with several types of labels and ticks. Various samples show you how the implement the gauges to create and customize all popular gauge types: car dashboard, clock, thermometer, compass etc. Learn more about Charting and Gauges for JavaScript at https://mindfusion.eu/javascript-chart.html.

Pie Chart with Custom Labels in WinForms

In this tutorial we will build the following pie chart using MindFusion Charts and Gauges for WinForms library:

This is a PieChart with a custom Series class that extends the capabilities of a standard PieSeries We need to create a custom Series class because we want the inner labels to follow a special format and we want the outer labels to be rendered as legend items not near pie pieces.

You can download the source code of the sample together with the MindFusion libraries used from the link at the bottom of the post.

I. General Setup

We create an empty WinForms application in C# with Visual Studio. We create a folder called References and there we copy the MindFusion.*.dll -s that we will need. They are:

MindFusion.Charting.dll
MindFusion.Charting.WinForms.dll
MindFusion.Common.dll

We reference those files in our project: we right-click the References folder in the Solution Explorer and click on “Add Reference”. Then we browse to our local References folder and add the 3 dll-s.

We have installed MindFusion Charts and Gauges from the website: http://mindfusion.eu/ChartWinFormsTrial.zip and now we need only to find the PieChart control, drag and drop it onto the WinForms Form of our application.

II. The Custom Pie Series

When you create a custom series you need to implement the Series interface. You need to declare several methods and properties, and one event. Let’s start with the constructor.

We need our chart to use one array with data and one array with labels. We declare two class variables for that and assign to them the values that we receive for them in the constructor. We name the new class CustomPieSeries:

public class CustomPieSeries : Series
{
	public CustomPieSeries(IList data, IList legendLabels )
	{
		values = data;		
		_legendLabels = legendLabels;

		//sum up all pie data
		total = 0.0;
		for (int i = 0; i < data.Count; i++)
			total += data[i];
	}

	IList values;	
	IList _legendLabels;
        double total = 0L;
}

We have added a new class variable called total. It is needed to keep the sum of all data for the chart. We will use this variable when we calculate the percent value of each pie piece.

The SupportedLabels property of type LabelKinds is the way to set which labels will be rendered by the new series. We want tooltips, inner labels and legend labels. There is no special enum field for legend labels. You just set which labels form the series should be rendered as legend items. We decide to use for this the ZAxisLabel, because it is not drawn anywhere on the pie chart and we won’t see it doubled by the legend labels. So, we say that the chart supports ZAxisLabels and we will tell the series that the ZAxisLabels must be rendered in the legend. We will do this later.

public LabelKinds SupportedLabels
{
	get { return LabelKinds.InnerLabel | LabelKinds.ToolTip | LabelKinds.ZAxisLabel; }
}

The GetLabel method is the place where we must return the correct label according to the type and position of the label, which are provided as arguments.

public string GetLabel(int index, LabelKinds kind)
{
	double percent = (values[index] / total) * 100;
	if (kind == LabelKinds.InnerLabel)
		return percent.ToString("F2") + "%\n" + values[index].ToString();
	if (kind == LabelKinds.ToolTip)
		return "Number of interns: " + values[index].ToString("F0") + 
			"\nPercent of total: " + percent.ToString("F2") + "%";

	if (kind == LabelKinds.ZAxisLabel)
		return _legendLabels[index].ToString();

	return null;
}

Here we have the chance to work over the raw data that we have for the series and return the desired labels as a string. We want the inner label to appear as the data value together with its percent representation. We calculate the percent thanks to the total variable and format it in an appropriate way:

 if (kind == LabelKinds.InnerLabel)
	return percent.ToString("F2") + "%\n" + values[index].ToString();

We do the same with the tooltips. We add an explanation text to the tooltip of each piece:

if (kind == LabelKinds.ToolTip)
	return "Number of interns: " + values[index].ToString("F0") + 
		"\nPercent of total: " + percent.ToString("F2") + "%";

The ZAxisLabel is the easiest to do. It will be used by the legend and we perform no special formatting upon it – we just return the label corresponding to the given index.

if (kind == LabelKinds.ZAxisLabel)
		return _legendLabels[index].ToString();

Among the other notable members of the Series interface are the Dimensions and Title properties. Dimensions is the property that specifies how many data dimensions the series has. They are 1 for charts that use one array of data, 2 for axes that use X and Y data, and 3 for 3D charts, which need X, Y and Z data. In our case we return 1 as property value because pie charts, just like radar charts, use only one data array.

public int Dimensions
{
	get { return 1; }
}

The Title property returns the Series title. This is an important property but in our case we will not use it. A common use case for Title is to be rendered in legends. We will not render the Series title in the legend, so we return an empty string.

public string Title
{
	get { return ""; }
}

Building the CustomPieSeries is an easy task:

var values = new List { 23, 54, 17, 9 };
pieChart1.Series = new CustomPieSeries(
	values,				
	new List()
	{
		" <1 month", " <=3 months", " <=6 months", " >6 months"
	}
);

We create a new instance of our new class and assign it to the Series property of the PieChart control. We provide a list with the data and the labels that we want to appear as a legend.

III. The Legend

The legend in the PieChart control is regulated by the LegendRenderer property. We set the ShowSeriesElements property to true to let the chart know that we want the data from the series to be rendered as labels and not the title:

pieChart1.LegendRenderer.ShowSeriesElements = true;

Then we use the ElementLabelKind property to specify which labels we want to use in the legend. These are the ZAxisLabels:

pieChart1.LegendRenderer.ElementLabelKind = LabelKinds.ZAxisLabel;

The other properties are self-explanatory. We use the Title property to set the legend title and set a transparent brush for both the Background and the BorderStroke = “Duration”;

pieChart1.LegendRenderer.Background = new SolidBrush(Color.Transparent);
pieChart1.LegendRenderer.BorderStroke = new SolidBrush(Color.Transparent);

IV. Styling

Styling the chart is done through the Theme property and through styles. There are different style classes available and in our case we will use the PerElementSeriesStyle class. This class accepts as arguments for the brushes and strokes lists with lists that contain the brushes. Then, it colors each element in each series with the corresponding brush in the array at the corresponding index. Our PieChart needs just one list with brushes and strokes. The stroke thicknesses are also added as nested arrays:

pieChart1.Plot.SeriesStyle = new PerElementSeriesStyle()
{
	Fills = new List<List>()
	{
		new List()
		{
			new SolidBrush(Color.FromArgb(158, 212, 224)),
			new SolidBrush(Color.FromArgb(187, 236, 247)),
			new SolidBrush(Color.FromArgb(212, 204, 196)),
			new SolidBrush(Color.FromArgb(245, 210, 179))					         }
	},

	Strokes = new List<list>()
	{
		new List()
		{
			new SolidBrush(Color.White)
						
		}
	},
	StrokeThicknesses = new List<list>()
	{
		new List()
		{
			3.0
		}
	}
};

We also set some appearance properties through the Theme field:

pieChart1.Theme.DataLabelsFontSize = 10;
pieChart1.Theme.HighlightStroke = new SolidBrush(Color.FromArgb(237, 175, 120));
pieChart1.Theme.HighlightStrokeThickness = 4;

The HighlightStroke is used to mark the selected chart element by mouse hover. The DataLabelsFontSize is used not only by painting the inner labels but also by painting the labels in the legend.

Finally we set the Title of the chart:

pieChart1.Title = "Internship Statistics";

And that is the end of this tutorial. You can download the code for the chart together with the MindFusion.*.dll libraries used from this link:

Pie Chart with Custom Labels Source Code Download

You can refer to MindFusion helpful support team with any technical questions regarding the WinForms Charts & Gauges control. Use the forum at: https://mindfusion.eu/Forum/YaBB.pl?board=mchart_disc

About MindFusion Charts and Gauges for WinForms: MindFusion Charts and Gauges for WinForms offers a long list of features that enables developer to build any type of chart, gauge or dashboard. The smart API of the library provides the option different chart elements like plots, axes, labels, and series to be combined and arranged in order to build any type of custom looking chart. The library also supports out of the box the most common chart types together with a set of their widely used properties. The gauge control is indispensable part of the library and offers a linear and oval gauge together with a variety of samples that provide you with the most common types of gauges used: clock, compass, thermometer, car dashboard and more. More about MindFusion Charts and Gauges for WinForms at: https://mindfusion.eu/winforms-chart.html.

Combo Chart with the Free JS Chart Library

MindFusion Free Js Chart 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.

I. Setup

The chart needs an HTML Canvas element to render onto and we create one in our web page:

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

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

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>

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

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

II. Chart Settings

We create the chart control using the HTML Element of the Canvas:

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.

III. Chart Series

We create two series for the bars. Free JS Chart offers a variety of series types to choose from and we use two different series for the bars. The first one is 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 only two parameters – a list with the data and a list with the 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 null. Then we add the series to a collection:

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

and 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));

We add it to another collections.

The chart renders by 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 provides it with the collection of series 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 SeriesRenderer property that holds all renderers for the chart data. By default, a bar chart has a BarRenderer Now we add to this collection the LineRenderer that will draw the series in lseries as lines.

IV. 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 margin. 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 are the renders 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;

V. 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 the stroke thickness. Note that now we assign the new style to the seriesStyle property of the LineRenderer 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, style the legend and the grid. Finally, we customize the stroke that highlights chart elements when the user hovers with the mouse over them.

And that’s 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: http://mindfusion.eu/samples/javascript/free_chart/CombiChart.zip

You can find out more about MindFusion Free JS Chart library at https://mindfusion.eu/free-js-chart.html.

New Release for the Free JS Chart Library

MindFusion Free JS Chart has a new release with the following new features:

– All Series can accept now simple JavaScript array-s as arguments instead of Collections.List instances
– The ToolTip class is greatly extended with many new properties that allow you to customize the apparance and position of tooltips
– The Color.knownColors field lists all standard CSS color names
– Brush and Pen instances can be created with simple strings that specify the HTML code of the color as argument instead of Color objects.
– The yLabelAlignment property of BiaxialChart specifies horizontal alignment of Y-axis labels.
– Texts are now properly underlined when FontStyle.Underline is set.

Free JS Chart is MindFusion charting library that is offered free of charge for commercial use. No attribution is required.

More about MindFusion Free JS Chart at https://mindfusion.eu/free-js-chart.html