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Add Annotations

Annotations are graphical elements (different types of shapes, custom text, and so on) that you can render on your chart to make it more informative, while making it visually appealing.

In this article we'll create a Spline chart and add annotations using angularjs-fusioncharts component. A spline chart using annotations to highlight a particular anchor along with text is shown below:

FusionCharts will load here..
{
    "chart": {
        "caption": "Average Monthly Temperature in Texas",
        "yAxisName": "Average Monthly Temperature",
        "anchorradius": "5",
        "plotToolText": "Average temperature in $label is <b>$dataValue</b>",
        "showHoverEffect": "1",
        "showvalues": "0",
        "numberSuffix": "°C",
        "theme": "fusion",
        "anchorBgColor": "#72D7B2",
        "paletteColors": "#72D7B2"
    },
    "annotations": {
        "groups": [
            {
                "id": "anchor-highlight",
                "items": [
                    {
                        "id": "high-star",
                        "type": "circle",
                        "x": "$dataset.0.set.7.x",
                        "y": "$dataset.0.set.7.y",
                        "radius": "12",
                        "color": "#cc0000",
                        "border": "2",
                        "borderColor": "#0075c2"
                    },
                    {
                        "id": "label",
                        "type": "text",
                        "text": "Hottest Month",
                        "fillcolor": "#0075c2",
                        "rotate": "90",
                        "x": "$dataset.0.set.7.x+75",
                        "y": "$dataset.0.set.7.y-2"
                    }
                ]
            }
        ]
    },
    "data": [
        {
            "label": "Jan",
            "value": "1"
        },
        {
            "label": "Feb",
            "value": "5"
        },
        {
            "label": "Mar",
            "value": "10"
        },
        {
            "label": "Apr",
            "value": "12"
        },
        {
            "label": "May",
            "value": "14"
        },
        {
            "label": "Jun",
            "value": "16"
        },
        {
            "label": "Jul",
            "value": "20"
        },
        {
            "label": "Aug",
            "value": "22"
        },
        {
            "label": "Sep",
            "value": "20"
        },
        {
            "label": "Oct",
            "value": "16"
        },
        {
            "label": "Nov",
            "value": "7"
        },
        {
            "label": "Dec",
            "value": "2"
        }
    ]
}

The code to render the above chart is given below:

//  Require AngularJS 
var angular = require('angular');

// Require FusionCharts 
var FusionCharts = require('fusioncharts');

// Include angularjs-fusioncharts 
require('angularjs-fusioncharts');

// Require Chart modules 
var Charts = require('fusioncharts/fusioncharts.charts');

// Require Fusion theme
var FusionTheme = require('fusioncharts/themes/fusioncharts.theme.fusion');

// Initialize Charts with FusionCharts instance
Charts(FusionCharts);

// Initialize FusionTheme with FusionCharts instance
FusionTheme(FusionCharts);

var myApp = angular.module("myApp", ["ng-fusioncharts"]);
myApp.controller("MyController", ["$scope", function($scope){
    // datasource
    $scope.myDataSource = {
        "chart": {
            "caption": "Average Monthly Temperature in Texas",
            "yAxisName": "Average Monthly Temperature",
            "anchorradius": "5",
            "plotToolText": "Average temperature in $label is <b>$dataValue</b>",
            "showHoverEffect": "1",
            "showvalues": "0",
            "numberSuffix": "°C",
            "theme": "fusion",
            "anchorBgColor": "#72D7B2",
            "paletteColors": "#72D7B2"
        },
        "data": [{
            "label": "Jan",
            "value": "1"
        }, {
            "label": "Feb",
            "value": "5"
        }, {
            "label": "Mar",
            "value": "10"
        }, {
            "label": "Apr",
            "value": "12"
        }, {
            "label": "May",
            "value": "14"
        }, {
            "label": "Jun",
            "value": "16"
        }, {
            "label": "Jul",
            "value": "20"
        }, {
            "label": "Aug",
            "value": "22"
        }, {
            "label": "Sep",
            "value": "20"
        }, {
            "label": "Oct",
            "value": "16"
        }, {
            "label": "Nov",
            "value": "7"
        }, {
            "label": "Dec",
            "value": "2"
        }]
    };
    // annotations object
    $scope.annotations = {{
        "groups": [{
            "id": "anchor-highlight",
            "items": [{
                "id": "high-star",
                "type": "circle",
                "x": "$dataset.0.set.7.x",
                "y": "$dataset.0.set.7.y",
                "radius": "12",
                "color": "#cc0000",
                "border": "2",
                "borderColor": "#0075c2"
            }, {
                "id": "label",
                "type": "text",
                "text": "Hottest Month",
                "fillcolor": "#0075c2",
                "rotate": "90",
                "x": "$dataset.0.set.7.x+75",
                "y": "$dataset.0.set.7.y-2"
            }]
        }]
    };
}]);

Now, use the fusioncharts directive in a template. The HTML template is given below:

<div ng-app="myApp">
  <div ng-controller="MyController"> 
    <!--Add annotations to the chart through annotations attribute-->
    <fusioncharts
        type="spline"
        width="700"
        height="400"
        annotations="{{annotations}}"
        dataFormat="json"
        datasource="{{myDataSource}}">
    </fusioncharts>
  </div>
</div>

The above chart has been rendered using the following steps:

  1. Include the necessary libraries and components using require. For example, angularjs-fusioncharts, fusioncharts, etc.

  2. Add the chart and the theme as dependencies to the core.

  3. Store the chart configurations in a variable (myApp).

  4. In the dataSource, create an annotations object to specify the cosmetics and functionalities of the annotation.

  5. Add the <div> with an fc-chart directive in your HTML, assuming that it is inside a controller named MyController. In the div:

    • Set the chart type as spline. For Spline chart, the alias is spline. Find the complete list of chart types with their respective alias here.
    • Set the width and height (in pixels).
    • Embed the annotations from annotations object.
    • Set the dataFormat as JSON.
    • Embed the json data from dataSource.