[SOLVED] Save jzy3d Chart in PDF using DynamicReports

I'm using DynamicReports API to create a PDF report displaying the results of my Java application (tables and charts). One of the chart I have to display is a 3D Surface Plot build using jzy3d 0.9.0.

Here is my code:

import static net.sf.dynamicreports.report.builder.DynamicReports.*;
import net.sf.dynamicreports.examples.Templates;
import net.sf.dynamicreports.examples.complex.invoice.InvoiceDesign;
import net.sf.dynamicreports.examples.complex.sales.SalesDesign;
import net.sf.dynamicreports.jasper.builder.JasperReportBuilder;
import net.sf.dynamicreports.report.constant.HorizontalImageAlignment;
import net.sf.dynamicreports.report.constant.HorizontalTextAlignment;
import net.sf.dynamicreports.report.constant.PageType;
import net.sf.dynamicreports.report.constant.VerticalImageAlignment;
import net.sf.dynamicreports.report.constant.VerticalTextAlignment;
import net.sf.dynamicreports.report.builder.chart.PieChartBuilder;
import net.sf.dynamicreports.report.builder.component.ComponentBuilder;
import net.sf.dynamicreports.report.builder.component.ComponentBuilders;
import net.sf.dynamicreports.report.builder.component.TextFieldBuilder;
import net.sf.dynamicreports.report.builder.style.FontBuilder;
import net.sf.dynamicreports.report.builder.style.StyleBuilder;
import net.sf.dynamicreports.report.constant.PageOrientation;
import net.sf.dynamicreports.report.datasource.DRDataSource;
import net.sf.jasperreports.engine.JRDataSource;
import net.sf.dynamicreports.jasper.builder.export.Exporters;
import net.sf.dynamicreports.report.builder.column.TextColumnBuilder;
import net.sf.dynamicreports.report.builder.component.HorizontalListBuilder;
import javax.swing.JFrame;
import com.fairdynamics.components.FDPalette;
import com.fairdynamics.components.FDGlassPane;
import com.fairdynamics.components.FDOptionPane;
import fairdynamics.lyrica.UI_VisualAnalytics.UIRespondersHeatMap.HeatMapDetails;
import javax.swing.ImageIcon;
import org.jzy3d.maths.*;
import org.jzy3d.plot3d.builder.*;
import org.jzy3d.plot3d.builder.concrete.OrthonormalGrid;
import org.jzy3d.colors.ColorMapper;
import org.jzy3d.colors.colormaps.ColorMapRainbow;
import org.jzy3d.plot3d.primitives.Shape;
import org.jzy3d.chart.Chart;
import org.jzy3d.plot3d.rendering.canvas.Quality;
import org.jzy3d.chart.ChartLauncher;
import org.jzy3d.plot3d.builder.Mapper;

public class UI_ReportBuilder3 extends JasperReportBuilder{
    protected final FontBuilder font18 = stl.font("Roboto Light",false,false,18);
    protected final FontBuilder font16 = stl.font("Roboto Light",false,false,16);
    protected final FontBuilder font14 = stl.font("Roboto Light",false,false,14);
    protected final FontBuilder font12 = stl.font("Roboto Light",false,false,12);
    protected final FontBuilder font10 = stl.font("Roboto Light",false,false,10);
    protected final StyleBuilder titleStyle = stl.style(font12).setVerticalTextAlignment(VerticalTextAlignment.TOP).setForegroundColor(FDPalette.primaryColor);
    protected final StyleBuilder mainTitleStyle = stl.style(font18).setVerticalTextAlignment(VerticalTextAlignment.TOP).setForegroundColor(FDPalette.primaryColor);
    protected final StyleBuilder subTitleStyle = stl.style(font14).setVerticalTextAlignment(VerticalTextAlignment.TOP).setForegroundColor(FDPalette.primaryColor);
    protected final StyleBuilder footerStyle = stl.style(font10).setVerticalTextAlignment(VerticalTextAlignment.MIDDLE).setForegroundColor(FDPalette.secondaryText);
    protected final StyleBuilder colStyle = stl.style(font12).setVerticalTextAlignment(VerticalTextAlignment.MIDDLE);   

    public UI_ReportBuilder3() {        
        try{
            this
            .setTemplate(Templates.reportTemplate)
            .setPageFormat(PageType.A4,PageOrientation.PORTRAIT)
            .setPageMargin(margin(40))
            .pageFooter(
                    cmp.text("Footer").setStyle(footerStyle).setHorizontalTextAlignment(HorizontalTextAlignment.CENTER)
                )
            .title(
                    cmp.horizontalList().add(
                        cmp.text("TITLE").setStyle(mainTitleStyle).setHorizontalTextAlignment(HorizontalTextAlignment.LEFT)
                    )
                    .setFixedHeight(32)
                )
            .summary(
                    cmp.multiPageList(cmp.image(createHeatMap().screenshot())
                        )
                )
            .show()
            ;
        }catch(Exception e){
            e.printStackTrace();
        }
    }


    private org.jzy3d.chart.Chart createHeatMap(){          
        // Define a function to plot
        Mapper mapper = new Mapper() {
            public double f(double x, double y) {
                return 10 * Math.sin(x / 10) * Math.cos(y / 20) * x;
            }
        };

        // Define range and precision for the function to plot
        Range range = new Range(-150, 150);
        int steps = 50;

        // Create a surface drawing that function
        org.jzy3d.plot3d.primitives.Shape surface = Builder.buildOrthonormal(new OrthonormalGrid(range, steps, range, steps), mapper);
        surface.setColorMapper(new ColorMapper(new ColorMapRainbow(), surface.getBounds().getZmin(), surface.getBounds().getZmax(), new org.jzy3d.colors.Color(1, 1, 1, .5f)));
        surface.setFaceDisplayed(true);
        surface.setWireframeDisplayed(false);
        surface.setWireframeColor(org.jzy3d.colors.Color.BLACK);

        // Create a chart and add the surface
        org.jzy3d.chart.Chart chart = new org.jzy3d.chart.Chart(Quality.Advanced);
        chart.getScene().getGraph().add(surface);

        return chart;
    }

}

This code works only if I call the method ChartLauncher.openChart(chart) (consequently opening a frame with the chart displayed in) from createHeatMap() before returning chart, otherwise createHeatMap().screenshot() always returns null. But what if I need to create and export a PDF of this chart without displaying the chart itself in my java application?

NOTE: if possible, I'd prefer to use jzy3d 0.9.0 and not jzy3d 0.9.1 because otherwise I should modify a lot of code already written and tested.