Point Labels

The point labels options are used to configure the point labels that are shown on the perimeter of the scale. They can be found in the pointLabels sub options object. Note

caution

The point labels can be ONLY applied to radial axes.
These options only apply if display is true.

The RadialPointLabels provides all set and get methods to manage the configuration, as following:

// creates a radial axis 
RadialAxis axis = new RadialAxis(chart);
// enables point labels
axis.getPointLabels().setDisplay(true);
// sets and gets the color value
axis.getPointLabels().setColor(HtmlColor.RED);

IsColor color = axis.getPointLabels().getColor();

Table with options:

Name	Type	Scriptable	Description
backdropColor	String - IsColor	Yes	Background color of the point label.
backdropPadding	Padding	-	The padding of label backdrop. See padding documentation for more details.
borderRadius	int - BarBorderRadius	Yes	The border radius of the point label (in pixels).
centerPointLabels	boolean	-	If true, point labels are centered.
display	boolean - Display	-	If true, point labels are shown. When Display.AUTO, the label is hidden if it overlaps with another label.
color	String - IsColor	Yes	Color of point labels.
font	IsFont	Yes	Font of point labels.
padding	int	Yes	Padding between chart and point labels, in pixel.

The further customization of point labels, a callback is provided.

Scriptable

Scriptable options at grid level accept a callback which is called for each of the underlying data values. See more details in Configuring charts section.

All scriptable options callbacks will get a ScaleContext instance.

// creates a radial axis 
RadialAxis axis = new RadialAxis(chart);
// enables point labels
axis.getPointLabels().setDisplay(true);
// sets the option by a callback 
axis.getPointLabels().setColor(new ColorCallback<ScaleContext>(){

   @Override
   public IsColor invoke(ScaleContext context){
      // logic
      return color;
   }
});

The following options can be set by a callback:

Name	Callback	Returned types
backdropColor	ColorCallback<ScaleContext>	String - IsColor
borderRadius	BorderRadiusCallback<ScaleContext>	int - BarBorderRadius
color	ColorCallback<ScaleContext>	String - IsColor
font	FontCallback<ScaleContext>	FontItem
padding	SimplePaddingCallback	int

Callback

Callback implementation can transform data labels to point labels. The default implementation simply returns the current string.

To apply an own callback, you can set a PointLabelCallback instance to the axis options, as following:

// creates a radial axis 
RadialAxis axis = new RadialAxis(chart);
// enables point labels
axis.getPointLabels().setDisplay(true);
// sets callback
axis.getPointLabels().setCallBack(new PointLabelCallback(){

   /**
    * Callback function to transform data labels to point labels. The default implementation simply returns the current string.
    * 
    * @param axis axis instance where this callback as been defined
    * @param item label of current label
    * @param index index of the label
    * @return new label to apply to point label
    */
    @Override
    public String onCallback(Axis axis, String item, int index){
      // logic
      return item;
   }
         
});

The callback can return a string (for single line) or a list of strings (for multiple lines).