GroupDocs.Signature を使用したスタンプによる署名

using System;
using System.IO;
using System.Drawing;
using GroupDocs.Signature;
using GroupDocs.Signature.Domain;
using GroupDocs.Signature.Options;

string filePath = "sample.pdf";
using (Signature signature = new Signature(filePath))
{
    //コードはここに入力します
}

StampSignOptions options = new StampSignOptions()
{
    Left = 50,
    Top = 150,                    
    Width = 200,
    Height = 200
};

StampLine outerLine = new StampLine();
outerLine.Text = " * European Union ";
outerLine.TextRepeatType = StampTextRepeatType.FullTextRepeat;
outerLine.Font.Size = 12;
outerLine.Height = 22;
outerLine.TextBottomIntent = 6;
outerLine.TextColor = Color.WhiteSmoke;
outerLine.BackgroundColor = Color.DarkSlateBlue;
options.OuterLines.Add(outerLine);
StampLine innerLine = new StampLine();
innerLine.Text = "John Smith";
innerLine.TextColor = Color.MediumVioletRed;
innerLine.Font.Size = 20;
innerLine.Font.Bold = true;
innerLine.Height = 40;
options.InnerLines.Add(innerLine);

string outputFilePath = Path.Combine("Your Document Directory", "SignWithStamp", fileName);
SignResult result = signature.Sign(outputFilePath, options);
Console.WriteLine($"\nSource document signed successfully with {result.Succeeded.Count} signature(s).\nFile saved at {outputFilePath}.");