Data labels in the pie chart can be displayed inside or outside the pie slice. The display location of data labels can be set using the labelPosition attribute in the <Pie2DSeries> element tag.
This sample pie chart is to show how to display data labels inside and outside the pie slice.
If you set as labelPosition = "insideWithCallout", then the label of the pie slice which has enough space will be displayed inside, and the label of the pie slice which has no enough space will be displayed outside.
... <Pie2DChart ... > ''' <Pie2DSeries labelPosition="insideWithCallout" ... > ... </Pie2DSeries> ... </Pie2DChart> ...