Bar chart API reference

• Example
• Using errorbars on the Bar chart
• The coordinates properties
• Properties
• Methods
• Data properties that are used on the bars
• Events
• Effects

Example

<script>
    // Some data that's to be shown on the Bar chart. To show a stacked or grouped chart
    // each number should be an array of more numbers instead (as shown below).
    data = [[5,3],[4,6],[4,5],[8,5],[3,6],[5,6],[8,5],[1,9],[4,3],[4,8],[5,8],[4,8]];
    labels = ['Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sep','Oct','Sep','Dec']

    new RGraph.SVG.Bar({
        id: 'chart-container',
        data: data,
        options: {
            marginLeft: 35,
            marginRight: 5,
            marginBottom: 35,
            marginTop: 45,
            backgroundGridVlines: false,
            backgroundGridBorder: false,
            textSize: 12,
            yaxis: false,
            yaxisScaleUnitsPre: '',  // Default
            yaxisScaleUnitsPost: 'k',
            yaxisScalePoint: '.',    // Default
            yaxisScaleThousand: ',', // Default
            yaxisScaleDecimals: 0,
            xaxisLinewidth: 3,
            xaxisTickmarks: false,
            xaxisLabels: '%{global:labels[%{index}]}',
            colors: ['#5cf', 'black'],
            marginInner: 9,
            marginInnerGrouped: 2,
            titleSubtitle: 'Turnover grouped by sales team',
            title: 'Monthly sales figures',
            titleBold: true,
            titleSize: 16,
            tooltips: '%{key}',
            tooltipsFormattedUnitsPre: '$',
            tooltipsFormattedUnitsPost: ',000',
            tooltipsFormattedKeyLabels: ['Sales team A','Sales team B'],
            tooltipsCss: {
                backgroundColor: '#333',
                fontWeight: 'bold',
                fontSize: '14pt',
                opacity: 0.85
            }
        }
    }).wave();
</script>

Using errorbars on the Bar chart

One of the features that the Bar chart has is the ability to display errorbars. This is demonstrated by the chart that's shown here. The errorbars property should be an array of objects but each element can be the following:

• null
• undefined
• A number
• An object with just the max property set
• An object with just the min property set
• An object with both the min and max properties set

An example of some code for a chart that has errorbars is shown below:

<script>
    new RGraph.SVG.Bar({
        id: 'cc',
        data: [8,4,8,6,3,5,8],
        options: {
            marginLeft: 50,
            title: 'A Bar chart with errorbars',
            textSize: 14,
            xaxisLabels: ['Mon','Tue','Wed','Thu','Fri','Sat','Sun'],
            errorbars: null,
            yaxis: false,
            backgroundGridBorder: false,
            backgroundGridVlines: false,
            spline: true,
            shadow: true,
            errorbars: [
                1,
                null,
                , // Undefined
                0,
                {min:1, max: 5},
                {min: 1},
                {max: 1}
            ]
        }
    }).draw();
</script>

The coordinates properties

The coordinates for the bars on the Bar chart are held in the following arrays:

• obj.coords
  All of the coordinates - that are appended to this array as the bars are drawn. Each element of the array is an object which consists of x, y, width, height, element and object properties. The element property is the svg rect element - and the object property is the RGraph object.
  
  
• obj.coords2
  Again, this is all of the coordinates - but arranged slightly differently. This is only used by stacked and grouped charts - each element is an array of that groups/stacks segments. Then each sub-element is an object which consists of x, y, width, height, element and object properties. The element property is the svg rect element - and the object property is the RGraph object.
  
  

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.

• Background properties
• Margin properties
• Color properties
• X-axis properties
• Y-axis properties
• Other text properties
• Tooltip properties
• Shadow properties
• Key properties
• Title properties
• Error bar properties
• Other properties

yaxisFormatter: function (obj, num)
{
}

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'
}

obj.set('horizontalLines', [
    {
        value: 'average',
        dashed: true,
        labelPosition:'left bottom'
    },
    {
        value: 10.48,
        label:'Value (%{value})',
        labelValueDecimals: 2,
        labelValueThousand: ',',
        labelValuePoint:'.',
        labelValueUnitsPre:'',
        labelValueUnitsPost:''
        //labelValueFormatter: function (opt)
        //{
        //    return opt.number;
        //}
    }
]);

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 method can be used to get a y-axis coordinate for a value when you're doing custom drawing on the chart. It returns null if the value is out of range.

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.

This method returns the relevant index for a bar given the X-coord The X-coord is retrieved from the event object that you pass it (the event.offsetX property.

This method returns the value from a click on the chart. You give it an event object and it returns the appropriate value (based on the scale) to you.

This method returns the approriate height for a value that you give it. It's the value that you give it remember - not an event object.

Data properties that are used on the bars

The svg rect elements that represent the bars on the Bar chart have various data attributes added to them that hold various bits of information. These are:

• data-original-x
• data-original-y
• data-original-width
• data-original-height
• data-index
• data-subindex (only used in grouped or stacked charts)
• data-sequential-index
• data-value
• data-sequential-tooltip

These can be retrieved by using standard dom methods:

obj.coords[0].element.getAttribute('data-sequential-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.Bar({
    id: 'chart-container',
    data: [4,8,6,4,5,2,3],
    options: {
    }
}).on('draw', function (obj)
{
    console.log('The draw event has fired');
    
}).draw();

Effects

• The grow effect (svg-bar-effect-grow.html in the download archive)
• The wave effect (svg-bar-effect-wave.html in the download archive)

<script>
    //
    // Optional callback function that's called when the effect is complete
    //
    function myCallback (obj)
    {
        // ...
    }

    obj = new RGraph.SVG.Bar({
        id: 'chart-container',
        data: [3,4,7,5,6,9,8],
        options: {
        }
    }).grow({frames: 60, callback: myCallback});
</script>