Data Markers
7 Jun 202324 minutes to read
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,
$("#container").ejChart({
// ...
//Adding shapes to series
series: [{
// ....
marker: {
shape: 'Diamond',
visible: true
}
},
{
// ...
marker: {
shape: 'Triangle',
visible: true
}
},
{
// ...
marker: {
shape: 'Hexagon',
visible: true
}
}],
// ....
});
Customizing marker
You can give color and opacity for the marker using fill and opacity property.
$("#container").ejChart({
series :[{marker : {
fill : "green",
opacity : 0.5
}
}]
});
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,
$("#container").ejChart({
// ...
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}
}
}],
// ...
});
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 horizontalTextAlignment and vertical text alignment.
$("#container").ejChart({
// ...
series: [{
// ...
marker: {
dataLabel: {
//Set text alignment to datalabel text
visible: true,
horizontalTextAlignment: "center",
verticalTextAlignment: "far"
}
}
}],
// ...
});
Label content can be formatted by using the template option. Inside the template, you can add the placeholder text “point.x” and “point.y” to display corresponding data points x & y value.
You can adorn the labels with background shapes by setting shape option.
The color for the datalabel text is set by using the fill property.
The following code example shows how to add background shapes and set template to data label.
The border color and width for the marker is added by using the border property.
<div id="template">
<div id="left">
<img src="../images/chart/icon_investments.png"/>
</div>
<div id="right">
<div id="point">#point.y#%</div>
</div>
</div>$("#container").ejChart({
// ...
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
}}
}],
// ...
});
The appearance of the labels can be customized by using the font and offset options. The color, fontFamily, fontStyle, fontWeight, opacity and size of font can also be customized. The offset option is used to move the labels vertically. Also, labels can be rotated by using the angle option.
The following code example shows how to rotate datalabel text and customize the font.
$("#container").ejChart({
// ...
series: [{
// ...
marker: {
dataLabel: {
visible: true,
//Rotate data label and customize the font
angle: "300",
offset: 15,
font: { color: "black", size:"13px" }
}
}
}],
// ...
});
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.
$("#container").ejChart({
// ...
series:[{
// ....
marker: {
dataLabel: {
visible: true,
// Place the datalabel text position in the center of the rectangle
textPosition: "middle"
// ...
} }
}],
// .....
});
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,
$("#container").ejChart({
// ...
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'
}],
// ...
});
The following screenshot displays the labels when the labelPosition is set as inside position.
The following screenshot displays the labels when the labelPosition is set as outsideExtended position.
The label can be wrapped for pie, doughnut, funnel, and pyramid series by setting the enableWrap property. The maximum label width for data label can be specified using maximumLabelWidth property.
$("#container").ejChart({
// . . .
series:[
{
//. . .
marker: {
dataLabel: {
// enable the dataLabel
visible: true,
// enable the wrapping option
enableWrap: true,
// set the maximumLabelWidth of the data label
maximumLabelWidth: 32
//. . .
}
}
// . . .
]}
// . . .
});
Binding label from the datasource
You can bind the text value to the datalabel from the datasource and then you need to map the text value field with the textMappingName properties respectively.
//data source for chart with label
var chartData = [
{ month: 'Jan', sales: 35, Text: "January" },
{ month: 'Feb', sales: 28, Text: "February" },
//...
];
$("#container").ejChart({
// ...
series: [{
// ...
marker: {
dataLabel: {
//Mapping the text name
visible : true,
textMappingName : "Text",
}
}
}],
// ...
});Try it: JS Playground Sample
Binding fill color to the points from the datasource
You can bind the color value to the points from the datasource and then you need to map the color value field to the pointColorMappingName property respectively.
//data source for chart with fill color
var chartData = [
{ month: 'Jan', sales: 35, color: "red" },
{ month: 'Feb', sales: 28, color: "blue" },
//...
];
$("#container").ejChart({
// ...
series: [{
// ...
//Mapping the color values to the points
pointColorMappingName:"color",
}],
// ...
});Try it: JS Playground Sample
Contrast Color for the data label
To change the contrast color for the data label, you can set the enableContrastColor as true in the dataLabel property of the chart series.
When we enable this property, the data label text will be rendered in contrast color based on the segment on which it is placed.
If the data label is placed inside the data points segment, then that particular point’s color is taken. Else the chart area or chart background color is considered for deriving the contrast color.
$("#container").ejChart({
// ...
series: [{
// ...
marker: {
dataLabel: {
//Set the saturation color to datalabel text
visible : true,
enableContrastColor : true,
}
}
}],
// ...
});Show Edge labels
The partially visible data labels can be displayed inside chart area using showEdgeLabels property.
$("#container").ejChart({
series :[{
marker :{
dataLabel :{showEdgeLabels : true}
}
}]
});DataLabel border
The border color and width of the data label can be customized using border property.
$("#container").ejChart({
series :[{
marker :{
dataLabel :{
border : {
color : "green",
width : 2
}
}
}
}]
});Customize specific points
By using the ejChart, you can also customize the individual/specific markers with different colors, shape and also with different images.
There are two ways to achieve this based on how the data is fed to the series.
The margin property is used for providing the space in the left,right,top and bottom directions.
The required space for the datalabel text can also be customized by using the offset property. The horizontal and vertical offset of data label can be customized using x and y property.
The opacity of the data label can be customized using opacity property.
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. There are several options like angle, opacity, border color, width, connectorLine type, width, fill, font size, opacity, fontWeight, fontStyle, fontFamily, horizontalTextAlignment, margin left, right, top, bottom, shape, textPosition, verticalTextAlignment, visible, template and offset to customize the point data label.
$("#container").ejChart({
// ...
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 }],
}],
// ...
});
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,
$("#container").ejChart({
// ...
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"
}};
}
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 color and width of connector line can also be customized using connectorLine property.
The following code example illustrates this,
$("#container").ejChart({
// ...
series: [{
// ...
marker: {
dataLabel: {
visible: true,
// Set connector line type and customize the color,
connectorLine: { type: 'bezier', color: 'black', width: 1 }
// ...
} },
// ...
labelPosition: 'outsideExtended',
}],
// ...
});
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,
$("#container").ejChart({
// ...
//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 smartLabels
enableSmartLabels: true
}],
// ...
});