แสตมป์ในรูปแบบ PDF ผ่าน C#

var inputFile = Path.Combine(dataDir, "AddTextStamp.pdf");
var outputFile = Path.Combine(dataDir, "AddTextStamp_out.pdf");        
var pdfDocument = new Aspose.Pdf.Document(inputFile);
var textStamp = new Aspose.Pdf.TextStamp("Sample Stamp")
{
    Background = true,
    XIndent = 100,
    YIndent = 100,
    Rotate = Aspose.Pdf.Rotation.on90
};

textStamp.TextState.Font = Aspose.Pdf.Text.FontRepository.FindFont("Arial");
textStamp.TextState.FontSize = 14.0F;
textStamp.TextState.FontStyle = Aspose.Pdf.Text.FontStyles.Bold | Aspose.Pdf.Text.FontStyles.Italic;        
textStamp.TextState.ForegroundColor = Aspose.Pdf.Color.Aqua;        
pdfDocument.Pages[1].AddStamp(textStamp);

pdfDocument.Save(outputFile);