Bar chart API reference

Documentation about the Bar chart including information about all of the options that are available to you. The Bar chart is a very commonly used type of chart and is very versatile. As such there are lots of Bar chart demos available in the download that demonstrate what you can do with it.

• Example
• Interactive demo
• Properties
• Methods
• Errorbars
• Note about the data_arr array
• Events
• Effects

Example

<script>
    data   = [[3,5,6],[8,4,5],[4,9,6]];
    labels = ['Richard', 'Alex', 'Nick'];

    new RGraph.Bar({
        id: 'cvs',
        data: data,
        options: {
            xaxisTickmarksCount: 0,
            xaxisLinewidth: 5,
            backgroundGridVlines: false,
            backgroundGridBorder: false,
            yaxis: false,
            colors:[
                'Gradient(#faa:red)',
                'Gradient(#afa:green)',
                'Gradient(#aaf:blue)'
            ],
            textSize: 24,
            xaxisLabels: '%{global:labels[%{index}]}',
            marginLeft: 45,
            backgroundGrid: true,
            marginInner: 50,
            tooltips: '<b>Results</b><br />%{key}',
            tooltipsFormattedKeyLabels: ['06:00','12:00','18:00'],
            tooltipsFormattedKeyColors:['red','green','blue'],
            tooltipsFormattedUnitsPost: '%',
            tooltipsCss: {
                fontSize: '16pt',
                textAlign: 'left'
            },
            corners: 'round'
        }
    }).draw();
</script>

Interactive demo

As of August 2021 there's an online interactive demo of the Bar chart which you can use to try out the Bar chart and see some of the capabilities of RGraph.

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
• X axis properties
• Y axis properties
• Color properties
• Margin properties
• Labels and text properties
• Title properties
• Shadow properties
• Key properties
• Interactive features properties
• Miscellaneous properties

Background properties

X axis properties

Y axis properties

function myFormatter(opt)
{
    var num = Number(opt.number) * 5;

    return String(num)
}
obj.set('yaxisScaleFormatter', myFormatter);

function myFormatter(opt)
{
    var num = Number(opt.number) * 5;

    return String(num)
}
obj.set('yaxisScaleFormatter', myFormatter);

Color properties

Margin properties

Labels and text properties

<div style="margin-left: 50px; display: inline-block">
    <canvas id="cvs" width="650" height="250"></canvas>
</div>

<div style="margin-left: 50px; display: inline-block">
    <canvas id="cvs" width="650" height="250"></canvas>
</div>

Title properties

Shadow properties

Key properties

Interactive features properties

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',
    backgroundColor: 'black',
    color: 'white'
}

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',
    backgroundColor: 'black',
    color: 'white'
}

Miscellaneous properties

combinedEffectOptions: '{frames: 300}'

combinedEffectOptions: '{frames: 300}'

Methods

<script>
    obj.canvas.onclick = function (e)
    {
        RGraph.redraw();
    
        var canvas  = e.target,
            obj     = canvas.__object__,
            shape   = obj.getShape(e);

        if (shape) {
            var x      = shape.x,
                y      = shape.y,
                width  = shape.width,
                height = shape.height;
            
            obj.path(
                'b r % % % % s black f red',
                x, y, width, height
            );
        }
    }
</script>

This method is similar to the above, but only uses the X coordinate to determine the relevant bar.

This method can be used to get the value at a particular point or at the mouse coordinates, based on the scale that is in use. Not simply the coordinates of the mouse. The argument can either be an event object (for use in event listener functions) OR a two element array consisting of the X and Y coordinates (ie when you're not in an event listener function). It returns null if the mouse or coordinates are in the margin areas. An example:

bar.canvas.onclick = function (e)
{
    var obj   = e.target.__object__;
    var value = obj.getValue(e);
    
    // ...
}

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

This method can be used to set an event listener on an object. It operates in a similar way to the jQuery on() function. The first argument is the event that you wish to attach to and the second is the handler function. For example:

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

The exec function is documented 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.

The responsive() function is documented on its own page here.

Errorbars

Errorbars can allow you to show an upper and lower range for a particular bar like the bar-errorbars.html example page shows in the download archive. You can specify errorbars like this:

bar = new RGraph.Bar({
    id: 'cvs',
    data: [12,18,10,9,6,20,18],
    options: {
        xaxisLabels: ['Monday','Tuesday','Wednesday','Thursday','Friday','Saturday','Sunday'],
        shadow: false,
        colors: ['red'],
        colorsStroke: 'rgba(0,0,0,0)',
        errorbars: [ [5,3], [2,6], [5,15,'blue',5,45] ],
        errorbarsLinewidth: 2,   // The default linewidth
        errorbarsColor: 'gray',  // The default color
        errorbarsCapped: true,   // Whether the ends of the errorbar have terminating lines
        errorbarsCappedWidth: 14 // The default width of the caps
    }                
}).draw();

This would give you three errorbars and the elements of each errorbar array are (each one is optional):

• The upper extent of the errorbar
• The lower extent of the errorbar
• The color of this errorbar
• The linewidth of this errorbar
• The (total) width of the cap at the end of this errorbar

Note about the data_arr array

Events

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

• adjustbegin This event fires at the start of adjusting - like the standard mousedown event.
• adjust This event fires (repeatedly) during adjusting - like the standard mousemove event.
• adjustend This event fires at the end of adjusting - like the standard mouseup event.
• annotatebegin This event fires at the start of annotating - like the standard mousedown event.
• annotate This event fires (repeatedly) during annotating - like the standard mousemove event.
• annotateend This event fires at the end of annotating - like the standard mouseup event.
• annotateclear This event fires at the end of the RGraph.clearAnnotations() function.
• beforeclear This event fires at the start of the RGraph.clear() function.
• clear This event fires at the end of the RGraph.clear() function.
• click This is similar to the standard canvas click event but this only fires when you click on a bar - not the whole canvas.
• crosshairs This event fires when you have the crosshairs feature enabled and you move the mouse.
• beforecontextmenu This event fires when you have the contextmenu enabled and it is about to appear.
• contextmenu This event fires when you have the contextmenu enabled and it has been displayed.
• beforedraw This event fires at the start of the draw() method before anything has been done.
• firstdraw This event fires at the end of the draw() function - but only the first time that the draw() function is called.
• draw This event fires at the end of the draw() function.
• beforeinteractivekey When you're using the interactive key this event fires just before the key and chart are highlighted.
• afterinteractivekey When you're using the interactive key this event fires just after the key and chart are highlighted.
• keyclick This event fires when you click on the key - you don't have to be using the interactive key however.
• mousemove This event is similar to the standard mousemove event but only fires when you move the mouse over a bar on the chart.
• mouseover This event is similar to the standard mouseover event but only fires when you move the mouse over a bar on the chart.
• mouseout This event is similar to the standard mouseout event but only fires when you move the mouse away from a bar on the chart that you've previously hovered over.
• beforetooltip This event fires at the start of the tooltip showing process.
• tooltip This event fires after a tooltip has been shown.

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

Effects

• The wave effect (effects-bar-wave.html in the download archive)
• The grow effect (effects-bar-grow.html in the download archive)
• The colorwave effect (effects-bar-color-wave.html in the download archive)

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

    obj = new RGraph.Bar({
        id: 'cvs',
        data: [3,4,7,5,6,9,8],
        options: {
            marginLeft: 35,
            marginInner: 60
        }
    }).wave({frames: 60}, myCallback);
    // .grow({frames: 60}, myCallback);
</script>