Я решил проблему.(используя iTextSharp) Вот мой код:
Graphics g = this.CreateGraphics();
bmp = new Bitmap(this.Size.Width, this.Size.Height + 10, g);
Graphics mg = Graphics.FromImage(bmp);
mg.CopyFromScreen(this.Location.X + 20, this.Location.Y + 25 ,40, 47, this.Size);
// Save the screenshot to the specified path that the user has chosen.
bmp.Save("Screenshot.png", ImageFormat.Png);
Document document = new Document();
document.SetMargins(1,1,1,1);
using (var stream = new FileStream("test.pdf", FileMode.Create, FileAccess.Write, FileShare.None))
{
PdfWriter.GetInstance(document, stream);
document.Open();
using (var imageStream = new FileStream("Screenshot.png", FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
{
var image = iTextSharp.text.Image.GetInstance(imageStream);
float maxWidth = document.PageSize.Width - document.LeftMargin - document.RightMargin;
float maxHeight = document.PageSize.Height - document.TopMargin - document.BottomMargin;
if (image.Height > maxHeight || image.Width > maxWidth)
image.ScaleToFit(maxWidth, maxHeight);
document.Add(image);
}
document.Close();
}