ASP.net生成文字圖片

string _FontName = Request["fontname"].ToString();
   int _FontSize = Convert.ToInt16(Request["fontsize"]);
   string _ShowName = Request["str"].ToString();
   
   
   Bitmap objBitmap = null; 
   Graphics g = null ; 
   
   Font stringFont = new Font(_FontName, _FontSize, FontStyle.Bold );
   StringFormat stringFormat = new StringFormat();
   stringFormat.FormatFlags = StringFormatFlags.NoWrap;

   try
   { 
    objBitmap = new Bitmap(1,1);
    g = Graphics.FromImage(objBitmap);
    SizeF stringSize = g.MeasureString(_ShowName, stringFont);
    int nWidth = (int)stringSize.Width; 
    int nHeight = (int)stringSize.Height; 
    g.Dispose(); 
    objBitmap.Dispose();

    objBitmap = new Bitmap(nWidth,nHeight); 
    g = Graphics.FromImage(objBitmap); 
    g.FillRectangle(new SolidBrush(Color.Yellow), new Rectangle(0,0,nWidth,nHeight)); 
    g.TextRenderingHint = TextRenderingHint.AntiAlias;
    g.DrawString(_ShowName, stringFont, new SolidBrush(Color.Black), new PointF(0, 0), stringFormat); 　 
    objBitmap.Save(Response.OutputStream, ImageFormat.Gif); 
   } 
   catch (Exception ee) 
   { 
    Response.Write(ee.ToString()); 
   } 
   finally 
   { 
    if (null != g) g.Dispose(); 
    if (null != objBitmap) objBitmap.Dispose(); 
    Response.End();
   }