Generate PDF from AdvancedDataGrid in FLEX

This code is used to generate PDF from AdvancedDataGrid in FLEX.
            private function generatePDF():void
            {
                 //ChDg.expandAll();
                //ChDg.height = 1800;
                myPDF = new PDF(Orientation.PORTRAIT, Unit.MM, Size.A4);
                myPDF.setDisplayMode(Display.FULL_PAGE,Layout.SINGLE_PAGE);
                var newPage:Page = new Page(Orientation.PORTRAIT,Unit.MM,Size.A4);
                myPDF.addPage(newPage);
                myPDF.addImage(ChDg,0,0,198,0,"JPG",100,1,"None","FitToPage",true,"");
               
                var bytes:ByteArray = myPDF.save(Method.LOCAL);
                var f:FileReference = new FileReference();
                f.save(bytes,"test.pdf");
            }