Wie man die Größe eines Diagramms mit XSSF (Apache POI 3.8)?

package le_package.poi_tests.xssflibrary;

import java.io.*;
import java.text.SimpleDateFormat;
import java.util.Date;

import org.apache.poi.openxml4j.opc.OPCPackage;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Name;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

public class POIReadFile {
    public static void main(String[] args) {
        try
        {           
            String jobName = "I am a job"; 
            String jobParent = "I am your father, Job.";        
            int rowNum = 40;
            int deface = 4;

            //Open Excel as OOXML
            XSSFWorkbook currentWorkbook = new XSSFWorkbook( OPCPackage.open("include/excelTemplate.xlsx"));

            //Get sheet in position 0
            Sheet currentSheet = currentWorkbook.getSheetAt(0);

            //Get sheet name for processing
            String sheetName = currentSheet.getSheetName();

            //Set values for headers
            currentSheet.getRow(1).getCell(0).setCellValue(jobName);            
            currentSheet.getRow(1).getCell(1).setCellValue(jobParent);              

            for (int i=0; i<rowNum; i++)
            {
                //Create row in a given position
                Row newRow = currentSheet.createRow(i+deface);

                //Create cell within row
                Cell newCell0 = newRow.createCell(0);
                Cell newCell1 = newRow.createCell(1);
                Cell newCell2 = newRow.createCell(2);
                String cellDate = "";

                /* Set CellType
                 *  0 - Numeric | 1 - String | 2 - Formula | 3 - Blank | 4 - Boolean | 5 - Error */
                newCell0.setCellType(0);
                cellDate = "3/"+(i+1)+"/2001 00:00:00";

                //Convert text into date
                Date currentCellDate = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss").parse(cellDate);
                //System.out.println(currentCellDate.toString()+"--"+cellDate);

                //Set CellValue
                newCell0.setCellValue(currentCellDate);


                cellDate = "4/"+(i+1)+"/2001 00:00:00"; 
                currentCellDate = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss").parse(cellDate);
                //System.out.println(currentCellDate.toString()+"--"+cellDate);             
                newCell1.setCellType(0);
                newCell1.setCellValue(currentCellDate);

                //setCellFormula sets the formula to be evaluated by excel, it doesn't need to start with '=' 
                newCell2.setCellFormula("A" + (i+deface+1) + "-B" + (i+deface+1));              
            }           

            //Search for named range
            Name rangeCell = currentWorkbook.getName("startRange");         
            //Set new range for named range 
            String reference = sheetName + "!$A$" + ( deface+1 ) + ":$A$" + ( rowNum+deface );          
            //Assigns range value to named range
            rangeCell.setRefersToFormula(reference);

            rangeCell = currentWorkbook.getName("endRange");            
            reference = sheetName + "!$B$"+(deface+1) + ":$B$" + (rowNum+deface);
            rangeCell.setRefersToFormula(reference);            

            rangeCell = currentWorkbook.getName("elapsedTime");
            reference = sheetName + "!$C$"+(deface+1) + ":$C$" + (rowNum+deface);
            rangeCell.setRefersToFormula(reference);

            //Create a fileStream to write into a file
            FileOutputStream newExcelFile = new FileOutputStream(jobName+".xlsx");

            //Write Stream
            currentWorkbook.write(newExcelFile);

            //Close New Excel File
            newExcelFile.close();           
        }
        catch (Exception e)
        {
            System.out.println("AAAAARGH, I was wounded by the following exception!:");
            e.printStackTrace();
            System.out.println("Sorry, your program is dead :(");
        }
    }
}