Radar chart API reference

• Example
• The angles (coordinates) properties
• Properties
• Methods
• Data properties that are used on the points
• Events

Example

<script>
    // Some data that's to be shown on the Radar chart. For multiple
    // lines it should be an array of arrays
    // data = [50,57,54,59,56];

    data = [
        [50,58,54,59,56],
        [90,84,86,98,86]
    ];

    new RGraph.SVG.Radar({
        id: 'chart-container',
        data: data,
        options: {
            colors: ['black', 'red'],
            tickmarksStyle: 'circle',
            tickmarksSize: 5,
            linewidth: 2,
            labels: ['John','Jay','June','Jocy','Joseph'],
            labelsBold: true,
            labelsItalic: true,
            labelsSize: 20,
            labelsOffset: 0,
            tooltips: '<i>Results for</i> <b>%{property:labels[%{index}]}</b><br />%{key}',
            tooltipsFormattedKeyLabels: ['Monday:','Tuesday:'],
            tooltipsFormattedUnitsPost:'%',
            tooltipsCss: {
                backgroundColor: '#333',
                fontWeight: 'bold',
                fontSize: '14pt',
                opacity: 0.85
            }
        }
    }).draw();
</script>

The angles (coordinates) properties

The details of the points on the Radar chart are held in two arrays called obj.angles and obj.angles2. The difference is how they're indexed. With the former, each point is appended to the array - so on a Radar chart with two datasets where each consists of eight points - the obj.angles array would result in having 16 elements - one per point.

The obj.angles2 array on the other hand is indexed by the relevant dataset - to which points are appended. So in the previous example, the angles2 array would have two elements - each of them being another array of eight elements (one per point). These elements are objects that consist of the following properties:

• object - The RGraph Radar chart object
• dataset - The dataset that pertains to the point
• index - The index of the point in the dataset
• x - The actual x-axis coordinate of the point
• y - The actual y-axis coordinate of the point
• cx - The center x-axis coordinate of the point
• cy - The center y-axis coordinate of the point
• r - The radius away from the center point that the point is
• angle - The angle used to get to the endpoint (the x-axis and y-axis coordinates)

Properties

You can use these properties to control how the chart appears. You can set them by including them in the options section of the configuration as shown above.

• Chart configuration properties
• Margin properties
• Background properties
• Color properties
• Labels and text properties
• Shadow properties
• Title properties
• Key properties
• Tooltip properties
• Highlight properties
• Scale properties
• Tickmark properties
• Other properties

tooltipsOverride: function (obj, opt)
{
    // Show tooltip
}

tooltipsFormattedKeyColorsCss : {
    border: "1px solid #ddd";
}

tooltipsFormattedListItems: [
    ['Bill','Jerry','Berty'], // First tooltip
    ['Gill','Carrie','Lucy'], // Second tooltip
    ['Pob','Nobby','Hilda']   // Third tooltip
]

.RGraph_tooltip ul#rgraph_formatted_tooltips_list li {
    text-align: left;
    color: yellow;
}

tooltips: {
    borderLeft: 'gray 2px solid',
    borderBottom: 'gray 2px solid'
}

tooltipsCss: {
    fontFamily: 'Verdana',
    fontSize: '20pt'
}

function (obj, num)
{
}

Methods

This can be used to get properties if necessary. It's normally used after the chart is drawn if you need to get parameters (if you're doing custom coding for example).

This can be used to set properties if necessary. It's normally used after the chart is drawn if you need to set additional parameters or change them.

This can be used to get the radius for the given value.

This function adds an event listener (such as beforedraw or draw) to the chart object. For example:

obj.on('draw', function (obj)
{
    // Put your code here
});

This function can be used to execute a function (immediately). It's not event-based (ie it doesn't run when something happens) - it just runs immediately - and only once. You might use it when you need to get something from the chart when it's drawn and then call the redraw function. Because this function only runs once the RGraph.SVG.redraw function would not cause a loop - which would happen if you used the draw event.

obj.exec(function (obj)
{
    // Put your code here
});

The responsive function helps your charts respond to different browser window sizes and screen resolutions. For example, for smaller screens, you might want to have angled labels or show shorter versions of them completely.

Update: There is now the responsive configuration option available to you and this is now the preferred method of configuration.

The responsive function and configuration option are documented on their own page here.

Data properties that are used on the points

The svg elements that represent the points on the Radar chart have two data attributes added to them that hold information about the indexes of the point. These are:

• data-index
• data-dataset

These can be retrieved by using standard dom methods:

element.getAttribute('data-index');

Events

RGraph supports custom events that allow you to easily add interactivity to your charts if required. The following events are available:

• beforedraw This event fires at the start of the draw method before anything has been done.
• draw This event fires at the end of the draw function.
• firstdraw This event fires at the end of the draw function - but only the first time and so it fires only once after the first draw call.
• beforetooltip This event fires at the start of the tooltip showing process.
• tooltip This event fires after a tooltip has been shown.

new RGraph.SVG.Radar({
    id: 'chart-container',
    data: [4,8,6,3,5,8,9],
    options: {
    }
}).on('tooltip', function (obj)
{
    console.log('The draw event has fired');
    
}).draw();