Data Markers

Data markers are used to provide information about the data point to the user. You can add a shape and label to adorn each data point.

Add Shapes

You can add shapes to any chart types but they are often used with line, area and spline series to indicate each data point. It is highlighted when you hover the mouse on the shape.

Shapes can be added to the chart by enabling the visible option of the marker property. There are different shapes you can add to the chart by using the shape option such as rectangle, circle, diamond etc.

The following code example explains on how to enable series marker and add shapes,

  • javascript
  • /// <reference path="tsfiles/jquery.d.ts" />
    /// <reference path="tsfiles/ej.web.all.d.ts" />
    
    module ChartComponent {
        $(function () {
            var chartSample = new ej.datavisualization.Chart($("#chartContainer"), {
                // ...
                //Adding shapes to series	
                series: [{
                    // ....
                    marker: {
                        shape: 'Diamond',
                        visible: true
                    }
                },
                 {
                     // ... 
                     marker: {
                         shape: 'Triangle',
                         visible: true
                     }
                 },
                  {
                      // ...
                      marker: {
                          shape: 'Hexagon',
                          visible: true
                      }
                  }],
    
               // ....
        });
     });
    }

    Marker Shapes

    Add image as marker

    Apart from the shapes, you can also add images to mark the data point by using the imageUrl option.

    The following code example illustrates this,

  • javascript
  • var chartSample = new ej.datavisualization.Chart($("#chartContainer"), {
                // ...      
                series: [{
                    // ...
                    marker: {
                     // Enable and customize the marker shape and size
                        visible: true,
                    // In order to set imageUrl, set shape as ‘image’ .
                        shape: "image",
                        imageUrl: "sun_annotation.png",
                        size: {width: 20, height: 20}
                    }
                }],
               // ...
        });

    Marker Image

    Add labels

    Data label can be added to a chart series by enabling the visible property in the dataLabel option. The labels appear at the top of the data point, by default.

    The following code example shows how to enable data label and set its horizontal and vertical text alignment.

  • javascript
  • var chartSample = new ej.datavisualization.Chart($("#chartContainer"), {
                // ...      
                series: [{
                    // ...
                    marker: {
                            dataLabel: {
                          //Set text alignment to data label text	
                                visible: true,
                                horizontalTextAlignment: "center",
                                verticalTextAlignment: "far"
                            }
                        }
                }],
               // ...
        });

    DataLabel Visibility

    Label content can be formatted by using the template option. Inside the template, you can add the placeholder text “point.x” and “point.y” to display corresponding data points x & y value.

    You can adorn the labels with background shapes by setting shape option.

    The following code example shows how to add background shapes and set template to data label.

  • html
  • <div id="template">
         <div id="left">
    	<img src="../images/chart/icon_investments.png"/>
         </div>
         <div id="right">
              <div id="point">#point.y#%</div>
         </div>
    </div>
  • javascript
  • var chartSample = new ej.datavisualization.Chart($("#chartContainer"), {
                // ...      
                series: [{
                   // ...
                   marker: {
    		            dataLabel: {
    			           visible: true,
                         //Set template to data label
                			template: 'template'
    		              }}		
                   }, {
    	           // ...
                   marker: {
    		             dataLabel: {
    			                visible: true,
                              //Add background shape to the data label
                                shape: 'Rectangle',
                                border: { width: 1, color: "red" }			     
                             }}
                        },{
                    // ...
                   marker: {
    		            dataLabel: {
    			           visible: true
    		             }}               
                  }],
    
               // ...
        });

    DataLabel Template

    The appearance of the labels can be customized by using the font and offset options. The offset option is used to move the labels vertically. Also, labels can be rotated by using the rotate option.

    The following code example shows how to rotate data label text and customize the font.

  • javascript
  • var chartSample = new ej.datavisualization.Chart($("#chartContainer"), {
                // ...      
                series: [{
                 // ...
                   marker: {
                            dataLabel: {
                                visible: true,
                               //Rotate data label and customize the font
                                angle: "300",    
                                offset: 15,
                                font: { color: "black", size:"13px" }
                             }
                        }		
                  }], 
               // ...
        });

    DataLabel Rotation and Font

    You can position the label to the top, center or bottom position of the segment by using the textPosition option for the chart types such as column, bar, stacked bar, stacked column, 100% stacked bar, 100% stacked column, candle and OHLC.

    The following code example shows how to set textPosition to display data label in the middle of the column rectangle.

  • javascript
  • var chartSample = new ej.datavisualization.Chart($("#chartContainer"), {
                // ... 
    	        series:[{
                      // ....
                       marker: {
                           dataLabel: {
                               visible: true,
                             // Place the data label text position in the centre of the rectangle
                               textPosition: "middle"
                              // ...
                           } } 
                   }],            
    
    	    // .....
        });

    DataLabel Position

    The label can be positioned inside or outside the perimeter of the series by using the labelPosition option for the chart types such as Pie and Doughnut, .

    The following code example shows how to set the labelPosition,

  • javascript
  • var chartSample = new ej.datavisualization.Chart($("#chartContainer"), {
                // ... 
    	        series:[{
                       points: [{ x: 'India', y: 24, text: 'India 24%' },
                                { x: 'Japan', y: 25, text: 'Japan 25%' },
                                { x: 'Australia', y: 20, text: 'Australia 20%' },
                                { x: 'USA', y: 35, text: 'USA 35%' },
                                { x: 'China', y: 23, text: 'China 23%' },
                                { x: 'Germany', y: 27, text: 'Germany 27%' },
                                { x: 'France', y: 22, text: 'France 22%' }],
    
                       marker: {
                           dataLabel: {
                               visible: true,
                               shape: 'rectangle',
                               font: {color: "white"}
                           }
                       },
                       type: 'doughnut',
                       //Display data label outside position 
                       labelPosition: 'outside'
                   }],            
    	    // ...
        });

    Pie and Doughnut DataLabel

    The following screenshot displays the labels when the labelPosition is set as inside position.

    Inside LabelPosition

    The following screenshot displays the labels when the labelPosition is set as outsideExtended position.

    OutsideExtended LabelPosition

    The label can be wrapped for pie, doughnut, funnel, and pyramid series by setting the enableWrap property.

  • javascript
  • var chartSample = new ej.datavisualization.Chart($("#chartContainer"), {
    
            // . . .   
    
        series:[
        {
                    //. . .
                marker: {
                     
                           dataLabel: {
                                     
                                 // enable the dataLabel
                              
                                 visible: true,
    
                                 // enable the wrapping option
    
                                 enableWrap: true,
               
                                 // set the maximumLabelWidth of the data label
    
                                 maximumLabelWidth: 32
                   
                                    //. . .
    
                          }
                   }
        
                 // . . .
    
            ]}
    
         // . . .
    
    });

    DataLabel Wrap

    Customize specific points

    By using the ejChart, you can also customize the individual/specific markers with different colors, shapes and also with different images.

    There are two ways to achieve this based on how the data is fed to the series.

    When the data is provided by using the points option, you can add marker for each data point or specific point by using the marker option as illustrated in the following code example.

  • javascript
  • var chartSample = new ej.datavisualization.Chart($("#chartContainer"), {
                // ...     
                series: [{
                        // ...
                        points: [  { x: 'Jan', y: 35 }, { x: 'Feb', y: 28 },   { x: 'Mar', y: 34 },
                          { x: 'Apr', y: 32 },{ x: 'May', y: 40 },  { x: 'Jun', y: 32 },
                          { x: 'Jul', y: 35 },  { x: 'Aug', y: 55,
                           marker: {
                             //Enable and customize the data label for a point
                                dataLabel: {
                                    visible: true,
                                    offset: -10,
                                    shape: "upArrow", font: { color: "white" , size: '11px' },
                                    margin: { left: 15, right: 15, top: 10, bottom: 10 },
                                    fill: "green"
                               } } },
    
                              { x: 'Sep', y: 38 },{ x: 'Oct', y: 30 },
                              { x: 'Nov', y: 25,
                                      marker: {
                                        //Enable and customize the data label for a point
                                         dataLabel: {
                                            visible: true,
                                            offset: -22,
                                            verticalTextAlignment: 'near',
                                            shape: "downArrow", font: { color: "white", size: '11px' },
                                            margin: { left: 15, right: 15, top: 10, bottom: 10 },                    
                                            fill: "red"
                               } } },  { x: 'Dec', y: 32 }],
    
                         }],
                     // ...
        });

    DataLabel Customization

    When the data is bound to the series by using the dataSource option, you can customize the points in the seriesRendering event as illustrated in the following code example,

  • javascript
  • var chartSample = new ej.datavisualization.Chart($("#chartContainer"), {
               // ...
                series: [{
                             //Add datasource and set xName and yName 
                             dataSource: chartData, 
                              xName: "month", 
                              yName: "sales"
                }],
                
               //Fires on rendering the series
                seriesRendering: "onSeriesRender",
    
                 // ...
    
        });
    
        //Define the seriesRendering client side event
      
         function onSeriesRender(sender) {
     
            
            //Enable and customize the dataLabel for a point using event
    
                sender.data.series.points[7].marker = {
                   dataLabel: {
                        visible: true,
                        offset: -10,
                        shape: "upArrow", font: { color: "white", size: '11px' },
                        margin: { left: 15, right: 15, top: 10, bottom: 10 },                    
                        fill: "green"
                    }};
    
                sender.data.series.points[10].marker = {
                     //Enable and customize the dataLabel for a point using event
                    dataLabel: {
                            visible: true,
                            offset: -22,
                            verticalTextAlignment: 'near',
                            shape: "downArrow", font: { color: "white", size: '11px' },
                            margin: { left: 15, right: 15, top: 10, bottom: 10 },                    
                            fill: "red"
                    }};
            }

    DataLabel Customize on SeriesRender

    Connect Line

    This feature is used to connect label and data point by using a line. It can be enabled only for Pie, Doughnut, Pyramid and Funnel chart types. Connector line types can be set as bezier or line by using the type option.

    The following code example illustrates this,

  • javascript
  • var chartSample = new ej.datavisualization.Chart($("#chartContainer"), {
                // ...      
                series: [{
    		      // ...
    		       marker: {
                       dataLabel: {
                                 visible: true,
                                 // Set connector line type and customize the color,
                                 connectorLine: { type: 'bezier', color: 'black' }
                                 // ...
                             }  },
                             // ...
                             labelPosition: 'outsideExtended',
                     }],
    
               // ...
        });

    Connector Line

    Smart labels

    Overlapping of the labels can be avoided by enabling the enableSmartLabels property. The default value is true for accumulation type series and false for other series types.

    The following code example shows how to enable smart labels,

  • javascript
  • var chartSample = new ej.datavisualization.Chart($("#chartContainer"), {
                // ...      
                //Initializing Series	
                series: [{
                    points: [{ x: 'Other Personal', y: 94658, text: 'Other Personal, 88.47%' },
                                 { x: 'Medical care', y: 9090, text: 'Medical care, 8.49%' },
    		                     { x: 'Housing', y: 2577, text: 'Housing, 2.40%' },
                                 { x: 'Transportation', y: 473, text: 'Transportation, 0.44%' },
                                 { x: 'Education', y: 120, text: 'Education, 0.11%' },
                                 { x: 'Electronics', y: 70, text: 'Electronics, 0.06%' }],
               	    marker:{
    		              dataLabel:{
    				          visible: true,
    				          shape: 'none',
    				          connectorLine: { type: 'bezier', color: 'black' },
    				          font: { size: '14px' }
                           }},
                   	       border: { width: 2, color: 'white' },
    		               type: 'pie',
                           labelPosition: "outsideExtended",
                           //Display data label outside position and enable smart labels
                           enableSmartLabels: true
                     }],
               // ...
        });

    EnableSmartLabels