/**
* @param field
* @param llx
* @param lly
* @param urx
* @param ury
*/
public void DrawSignatureAppearences(PdfFormField field, float llx, float lly, float urx, float ury)
{
PdfAppearance tp = PdfAppearance.CreateAppearance(writer, urx - llx, ury - lly);
tp.SetGrayFill(1.0f);
tp.Rectangle(0, 0, urx - llx, ury - lly);
tp.Fill();
tp.SetGrayStroke(0);
tp.SetLineWidth(1);
tp.Rectangle(0.5f, 0.5f, urx - llx - 0.5f, ury - lly - 0.5f);
tp.ClosePathStroke();
tp.SaveState();
tp.Rectangle(1, 1, urx - llx - 2, ury - lly - 2);
tp.Clip();
tp.NewPath();
tp.RestoreState();
field.SetAppearance(PdfAnnotation.APPEARANCE_NORMAL, tp);
}