| layout | post |
|---|---|
| title | Markers and data labels in Essential Javascript Chart | Syncfusion |
| description | Learn here about data markers support in Syncfusion Essential AngularJS Chart Control, its elements, and more. |
| platform | AngularJS |
| control | Chart |
| documentation | ug |
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.
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 e-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,
{% highlight html %}
<title>Essential Studio for AngularJS: Chart</title> });
</script>
</body>
{% endhighlight %}
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,
{% highlight html %}
<title>Essential Studio for AngularJS: Chart</title> });
</script>
</body>
{% endhighlight %}
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.
{% highlight html %}
<title>Essential Studio for AngularJS: Chart</title> });
</script>
</body>
{% endhighlight %}
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.
{% highlight html %}
});
</script>
</body>
{% endhighlight %}
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 datalabel text and customize the font.
{% highlight html %}
<title>Essential Studio for AngularJS: Chart</title> });
</script>
</body>
{% endhighlight %}
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.
{% highlight html %}
<title>Essential Studio for AngularJS: Chart</title> });
</script>
</body>
{% endhighlight %}
The label can be positioned inside or outside the perimeter of the series by using the e-labelPosition option for the chart types such as Pie and Doughnut, .
The following code example shows how to set the labelPosition,
{% highlight html %}
<title>Essential Studio for AngularJS: Chart</title> });
</script>
</body>
{% endhighlight %}
The following screenshot displays the labels when the e-labelPosition is set as inside position.
The following screenshot displays the labels when the e-labelPosition is set as outsideExtended position.
The label can be wrapped for pie, doughnut, funnel, and pyramid series by setting the enableWrap property.
{% highlight html %}
<title>Essential Studio for AngularJS: Chart</title> });
</script>
</body>
{% endhighlight %}
To change the contrast color for the data label, you can set the e-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.
{% highlight html %}
<title>Essential Studio for AngularJS: Chart</title> });
</script>
</body>
{% endhighlight %}
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 e-points option, you can add marker for each data point or specific point by using the e-marker option as illustrated in the following code example.
{% highlight html %}
<title>Essential Studio for AngularJS: Chart</title> });
</script>
</body>
{% endhighlight %}
When the data is bound to the series by using the e-dataSource option, you can customize the points in the e-seriesrendering event as illustrated in the following code example,
{% highlight html %} <title>Essential Studio for AngularJS: Chart</title>
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" }}; } </script>
{% endhighlight %}
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,
{% highlight html %}
<title>Essential Studio for AngularJS: Chart</title>{% endhighlight %}
Overlapping of the labels can be avoided by enabling the e-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,
{% highlight html %}
<title>Essential Studio for AngularJS: Chart</title>{% endhighlight %}
