<!-- Start 3D Pie Chart -->
<chart evaluationTime="Report" isShowLegend="false">
<reportElement x="125" y="375" width="300" height="200"/>
<!-- End 3D Pie Chart -->
As we can see from this example, the JRXML element to create a two-dimensional
pie chart is <pieChart> , and the JRXML element to create a three-dimensional pie
chart is called <pie3DChart> . Just like all JRXML chart elements, these elements
contain a <chart> sub-element. They also contain a <pieDataset> sub-element,
which in turn contains the <dataset> element for the chart, a <keyExpression>
sub-element, and a <valueExpression> sub-element. The <keyExpression> sub-
element contains a report expression indicating what to use as a key in the chart.
The <valueExpression> sub-element contains an expression used to calculate the
value for the key. The values we see to the left of the equal sign in the chart label
correspond to the <keyExpression> (aircraft model, in this case). The values we see
to the right of the equal sign in the chart label correspond to the <valueExpression>
(number of aircraft of a particular model, in this case).
In this example, the aircraft model is used as the key. It is represented by the report
field called model . The value to be used in the chart is the total number of aircrafts of
that model, represented by the totalAircraft report variable.
<pieChart> must contain a <piePlot> sub-element containing the chart's <plot>
element. <pie3Dchart> must contain an analogous <pie3DPlot> element. Although
<piePlot> has no attributes, <pie3DPlot> has a single optional attribute called
depthFactor . This attribute indicates the depth (how 'tall' or 'short' the pie chart is)
of the 3-D pie chart. Its default value is 0.2 .