Donut Chart
Donut charts act just like pie charts, except for an adjustable donut hole in the center of the chart. DonutChart is a subclass of PieChart, so all pie chart documentation also applies to donut chart.
Specifying Hole Radius
The hole radius of a donut chart can be specified by changing DonutChart.HoleRadiusPercentage. HoleRadiusPercentage
determines what percentage of the DonutChart is consumed by the donut hole, from 0.0
(0%) to 1.0
(100%).
A donut chart with a donut hole radius at 80%:
<charts:DonutChart HoleRadiusPercentage="0.8"/>