There are up to three (dependant on the pie style) visualisation options: 'show labels', 'show total' and 'show icon'.  'Show labels' can be selected alongside the other two however, 'show total' and 'show icon' cannot be selected simultaneously. 

This feature is available for each pie chart style. It will label each section of the pie chart with its dimension value and its size - as a percentage by default.

This will display the total figure for that metric in the centre of the pie chart.

If the metric has an icon attributed to it, this option will display it in the centre of the pie chart.