如何在 Apache poi 图表中重新定位 XDDFChartLegend 图例

问：

我正在使用 Apache POI 创建多个圆环图。当标签字符串大小很大并且添加更多标签时，我会遇到问题。在 Apache POI 文档中，我在 XDDFChartLegend 中没有找到可以调整边距的方法。我还希望这些标签适合分配给传奇的空间，无论大小。

在上图中，可以观察到

1. 当图例的字符串大小较大时，它会叠加在图表上。此外，还有 10 个传奇。但只显示 8 个。

2. 当图例的字符串大小较小时，将显示所有图例。

   public static XSSFChart createDoughnutChart(XSSFSheet sheet, String[] categories,Number[] values, String titleText, int col1, int row1, int col2, int row2) {
   XSSFDrawing drawing = sheet.createDrawingPatriarch();
   XSSFClientAnchor anchor = drawing.createAnchor(0, 0, 0, 0, col1, row1, col2, row2);
   
   XSSFChart chart = drawing.createChart(anchor);
   chart.setTitleText(titleText);
   chart.setTitleOverlay(false);
   
   XDDFChartLegend legend = chart.getOrAddLegend();
   legend.setPosition(LegendPosition.BOTTOM);
   legend.setOverlay(true);
   
   //setting legend size
   XDDFTextBody legendTextBody = new XDDFTextBody(legend);
   legendTextBody.getXmlObject().addNewBodyPr();
   legendTextBody.addNewParagraph().addDefaultRunProperties().setFontSize(6d);
   legend.setTextBody(legendTextBody);
   
   
   XDDFDataSource<String> cat = XDDFDataSourcesFactory.fromArray(categories);
   XDDFNumericalDataSource<Number> val = XDDFDataSourcesFactory.fromArray(values);
   XDDFDoughnutChartData data = (XDDFDoughnutChartData)chart.createData(ChartTypes.DOUGHNUT, null, null);
   data.setVaryColors(false);
   data.setHoleSize(50);
   XDDFChartData.Series series = data.addSeries(cat, val);
   
   chart.plot(data);
   
   // Do not auto delete the title; is necessary for showing title in Calc
   if (chart.getCTChart().getAutoTitleDeleted() == null) chart.getCTChart().addNewAutoTitleDeleted();
   chart.getCTChart().getAutoTitleDeleted().setVal(false);
   
   // Data point colors; is necessary for showing data points in Calc
   int pointCount = series.getCategoryData().getPointCount();
   for (int p = 0; p < pointCount; p++) {
       chart.getCTChart().getPlotArea().getDoughnutChartArray(0).getSerArray(0).addNewDPt().addNewIdx().setVal(p);
       chart.getCTChart().getPlotArea().getDoughnutChartArray(0).getSerArray(0).getDPtArray(p)
               .addNewSpPr().addNewSolidFill().addNewSrgbClr().setVal(XlsxService.getColor(p));
   }
   
   // Add data labels
   if (!chart.getCTChart().getPlotArea().getDoughnutChartArray(0).getSerArray(0).isSetDLbls()) {
       chart.getCTChart().getPlotArea().getDoughnutChartArray(0).getSerArray(0).addNewDLbls();
   }
   chart.getCTChart().getPlotArea().getDoughnutChartArray(0).getSerArray(0).getDLbls().addNewShowVal().setVal(true);
   chart.getCTChart().getPlotArea().getDoughnutChartArray(0).getSerArray(0).getDLbls().addNewShowSerName().setVal(false);
   chart.getCTChart().getPlotArea().getDoughnutChartArray(0).getSerArray(0).getDLbls().addNewShowCatName().setVal(false);
   chart.getCTChart().getPlotArea().getDoughnutChartArray(0).getSerArray(0).getDLbls().addNewShowPercent().setVal(false);
   chart.getCTChart().getPlotArea().getDoughnutChartArray(0).getSerArray(0).getDLbls().addNewShowLegendKey().setVal(false);
   
   // chart area (chartspace) without border line
   chart.getCTChartSpace().addNewSpPr().addNewLn().addNewNoFill();
   // changing background color
   if (chart.getCTChartSpace().getSpPr() == null) chart.getCTChartSpace().addNewSpPr();
   if (chart.getCTChartSpace().getSpPr().isSetSolidFill()) chart.getCTChartSpace().getSpPr().unsetSolidFill();
   chart.getCTChartSpace().getSpPr().addNewSolidFill().addNewSrgbClr().setVal(new byte[]{(byte)242, (byte)242, (byte)242});
   // set plot area size
   if (!chart.getCTChart().getPlotArea().isSetLayout()) {
       chart.getCTChart().getPlotArea().addNewLayout();
   }
   if (chart.getCTChart().getPlotArea().getLayout().isSetManualLayout()) {
       chart.getCTChart().getPlotArea().getLayout().unsetManualLayout();
   }
   chart.getCTChart().getPlotArea().getLayout().addNewManualLayout();
   chart.getCTChart().getPlotArea().getLayout().getManualLayout().addNewLayoutTarget().setVal(
           org.openxmlformats.schemas.drawingml.x2006.chart.STLayoutTarget.INNER);
   chart.getCTChart().getPlotArea().getLayout().getManualLayout().addNewXMode().setVal(
           org.openxmlformats.schemas.drawingml.x2006.chart.STLayoutMode.EDGE);
   chart.getCTChart().getPlotArea().getLayout().getManualLayout().addNewYMode().setVal(
           org.openxmlformats.schemas.drawingml.x2006.chart.STLayoutMode.EDGE);
   chart.getCTChart().getPlotArea().getLayout().getManualLayout().addNewX().setVal(0.10); //10% from left
   chart.getCTChart().getPlotArea().getLayout().getManualLayout().addNewY().setVal(0.10); //10% from top
   chart.getCTChart().getPlotArea().getLayout().getManualLayout().addNewW().setVal(0.80); //80% width
   chart.getCTChart().getPlotArea().getLayout().getManualLayout().addNewH().setVal(0.60); //60% height
   
   return chart;
   

   }