GemBox Spreadsheet : Why Save Excel to PDF PieChart cannot show same in Excel

Question

from Excel File

from PDF Export From Excel

This Code export Pie Chart

    //Pie Chart
    var pieChart = worksheet.Charts.Add(ChartType.Pie, "A27", "G45");
    pieChart.SelectData(worksheet.Cells.GetSubrange("G2:G6"), true, true);
    pieChart.DataLabels.LabelContainsValue = true;
    pieChart.DataLabels.LabelContainsPercentage = true;
    pieChart.DataLabels.ShowLeaderLines = true;
    pieChart.DataLabels.Separator = ", ";
    pieChart.Legend.IsVisible = true;
    pieChart.Legend.Position = ChartLegendPosition.Bottom;

    var printOptions = worksheet.PrintOptions;
    printOptions.FitWorksheetWidthToPages = 1;
    printOptions.FitWorksheetHeightToPages = 1;
    workbook.Save(ms, SaveOptions.PdfDefault);`enter code here`