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Change Chart Type at Runtime

FusionCharts Suite XT includes advanced features that let you add more context to your chart and make data visualization simpler. These features include chart updates, update chart type at runtime, and events.

This article focuses on how you can change the chart type of the chart at runtime using a Python function. The chart types used in the sample is:

  • Column 2D

  • Bar 2D

  • Pie 2D

A chart configured to change the chart type is shown below:

FusionCharts will load here..
{
    "chart": {
        "caption": "Countries With Most Oil Reserves [2017-18]",
        "subCaption": "In MMbbl = One Million barrels",
        "xAxisName": "Country",
        "yAxisName": "Reserves (MMbbl)",
        "numberSuffix": "K",
        "theme": "fusion"
    },
    "data": [
        {
            "label": "Venezuela",
            "value": "290"
        },
        {
            "label": "Saudi",
            "value": "260"
        },
        {
            "label": "Canada",
            "value": "180"
        },
        {
            "label": "Iran",
            "value": "140"
        },
        {
            "label": "Russia",
            "value": "115"
        },
        {
            "label": "UAE",
            "value": "100"
        },
        {
            "label": "US",
            "value": "30"
        },
        {
            "label": "China",
            "value": "30"
        }
    ]
}

The full code for the above sample is given below:

from django.shortcuts import render
from django.http import HttpResponse

# Include the `fusioncharts.py` the file which has required functions to embed the charts in HTML page
from ..fusioncharts import FusionCharts

# Loading Data from a Static JSON String
# It is an example to show how to attach event in the chart.
# The `chart` method is defined to load chart data from a JSON string.

def chart(request):

    # Create an object for the column2d chart using the FusionCharts class constructor
    column2d = FusionCharts("column2d", "ex1", '700', '400', "chart-1", "json", 
        # The chart data is passed as a string to the `dataSource` parameter.
        """{  
             "chart":
             {  
                "caption": "Countries With Most Oil Reserves [2017-18]",
                "subCaption": "In MMbbl = One Million barrels",
                "xAxisName": "Country",
                "yAxisName": "Reserves (MMbbl)",
                "numberSuffix": "K",
                "theme": "fusion"
             },
             "data": [{
                "label": "Venezuela",
                "value": "290"
            }, {
                "label": "Saudi",
                "value": "260"
            }, {
                "label": "Canada",
                "value": "180"
            }, {
                "label": "Iran",
                "value": "140"
            }, {
                "label": "Russia",
                "value": "115"
            }, {
                "label": "UAE",
                "value": "100"
            }, {
                "label": "US",
                "value": "30"
            }, {
                "label": "China",
                "value": "30"
            }]
        }""")        

    # returning complete JavaScript and HTML code, which is used to generate chart in the browsers. 
    return  render(request, 'dynamic-chart-type.html', {'output' : column2d.render(), 'chartTitle': 'Dynamic Chart Type Change'})

The HTML template to render the above chart is shown below:

<!DOCTYPE html>
<html>
<head>
  <title>FC-python wrapper</title>

<!-- If you are using downloaded FusionCharts libraries, uncomment the below code   -->

   <script type="text/javascript" src="//cdn.fusioncharts.com/fusioncharts/latest/fusioncharts.js"></script>
   <script type="text/javascript" src="//cdn.fusioncharts.com/fusioncharts/latest/themes/fusioncharts.theme.fusion.js"></script>

</head>
<body style="font-family:'Helvetica Neue', Arial; font-size: 16px;">
  <h3>{{ chartTitle|safe }}</h3>
        <script type="text/javascript">
            FusionCharts && FusionCharts.ready(function () {
            var trans = document.getElementById("controllers").getElementsByTagName("input");
            for (var i=0, len=trans.length; i<len; i++) {                
                if (trans[i].type == "radio"){
                    trans[i].onchange = function() {
                        changeChartType(this.value);
                    };
                }
            }
        });

        function changeChartType(chartType) {
            for (var k in FusionCharts.items) {
                if (FusionCharts.items.hasOwnProperty(k)) {
                    FusionCharts.items[k].chartType(chartType);
                }
            }
        };
    </script>
    <div align="center">
    <label style="padding: 0px 5px !important;">Select The Chart Type</label>
    </div>
    <br/>
    <div id="controllers" align="center" style="font-family:'Helvetica Neue', Arial; font-size: 14px;">
    <label style="padding: 0px 5px !important;">
        <input type="radio" name="div-size" checked value="column2d"/>Column 2D 
    </label>
    <label style="padding: 0px 5px !important;">
        <input type="radio" name="div-size" value="pie3d"/>Pie 3D
    </label>
    <label style="padding: 0px 5px !important;">
            <input type="radio" name="div-size" value="bar2d"/>Bar 2D
    </label>
    </div>
    <br/>
    <br/>
    <br/>
    <div style="width: 100%; display: block;" align="center">
    <div id="chartContainer">{{ output|safe }}</div>
    </div>
    <br/>
    <br/>
    <a href="/">Go Back</a>
</body>
</html>

The sample code provided above corresponds to the following tasks:

  1. Import and resolve dependencies:

    • render from django.shortcuts, and HttpResponse from django.http

    • FusionCharts from fusioncharts

  2. Define a function chart, which takes request as an argument:

    • Create a variable column2d, which is an instance of the FusionCharts class. As argument values for FusionCharts, pass the chart details and the configuration (JSON string):

      • Set the chart type as column2d. Find the complete list of chart types with their respective alias here.

      • Set the id as ex1.

      • Set the width and height of the chart in pixels. You can also provide them as percentages.

      • Set the renderAt as chart-1.

      • Set the dataFormat as json.

      • Embed the json data (string) as the value of dataSource.

    • Return the output of the render function (defined in FusionCharts):

      • Pass the request, which is also the only argument accepted by the chart function you are defining.

      • Pass the relative path of the HTML template, where the chart will be rendered.

      • Pass a dictionary:

        • Set the output to column2d.render().

        • Set the chartTitle to Example of event (product life cycle event).

When you change the values of id and renderAt, ensure that the corresponding changes are reflected in the HTML template. The string values for renderAt in the code, and the corresponding div id in the HTML template, should be the exact same.

Refer to Column 2D chart for more information on the configuration and data for this chart type. Alternatively, if your starting chart is Bar chart or Pie chart, you can use their respective pages as a source of detailed information for possible configuration and data.