thanks davide for your reply i tried above method but its not working the changes are not reflecting at screen
please view my source code and let me know what should i do?
PageContent content = new PageContent();
content.Create();//create content, do not forget.
content.GSSave();
Matrix mat = new Matrix( 1, 1, 100, 500 );
content.GSSetMatrix(mat);
mat.Destroy();
Page page = doc.GetPage(currentpage_num);
Document.DocFont dfont = doc.NewFontCID("DroidSansFallback", 1 |

;//bold and embed in horizontal writing
ResFont rfont = page.AddResFont(dfont);
content.TextBegin();
content.TextSetFont(rfont, 20);//set font and size
content.SetFillColor(0xff9801);
content.SetStrokeColor(0x10);
content.TextSetCharSpace(0);
content.TextSetWordSpace(0.3f);
content.TextSetLeading(20);
content.TextSetRenderMode(2);//fill and stroke
content.TextSetHScale(120);//set horizontal scale
content.DrawText(getDate());
content.TextEnd();
content.GSRestore();
//add content to page
page.AddContent(content, true);
content.Destroy();
PDFView pdf= new PDFView(getApplicationContext());
PDFVPage pdfd= new PDFVPage(doc,currentpage_num);
pdf.vRenderAsync(pdfd);