C#を使用してPDFファイルに画像スタンプを追加する方法を詳しく紹介します。

PdfDocument doc = new PdfDocument();
doc.LoadFromFile(@"E:\Visual Studio\Sample\template7\sample.pdf");

PdfPageBase page = doc.Pages[0];

PdfRubberStampAnnotation loStamp = new PdfRubberStampAnnotation(new RectangleF(new PointF(-5,-5), new SizeF(60, 60)));

PdfAppearance loApprearance = new PdfAppearance(loStamp);

PdfImage image = PdfImage.FromFile(@"C:\Users\Administrator\Pictures\sample.jpg");

PdfTemplate template = new PdfTemplate(160, 160);
template.Graphics.DrawImage(image, 0, 0);
loApprearance.Normal = template;
loStamp.Appearance = loApprearance;

page.AnnotationsWidget.Add(loStamp);

string output = "ImageStamp.pdf";
doc.SaveToFile(output);

using System;
using System.Drawing;
using System.Windows.Forms;
using Spire.Pdf;
using Spire.Pdf.Annotations;
using Spire.Pdf.Annotations.Appearance;
using Spire.Pdf.Graphics;

namespace addanimagestamptoaPDF_file
{
  public partial class Form1 : Form
  {
    public Form1()
    {
      InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {
      PdfDocument doc = new PdfDocument();
      doc.LoadFromFile(@"E:\Visual Studio\Sample\template7\sample.pdf");
 
      PdfPageBase page = doc.Pages[0];
      
      PdfRubberStampAnnotation loStamp = new PdfRubberStampAnnotation(new RectangleF(new PointF(-5, -5), new SizeF(60, 60)));
      PdfAppearance loApprearance = new PdfAppearance(loStamp);
      PdfImage image = PdfImage.FromFile(@"C:\Users\Administrator\Pictures\sample.jpg");
 
      PdfTemplate template = new PdfTemplate(160, 160);
      template.Graphics.DrawImage(image, 0,0);
      loApprearance.Normal = template;
      loStamp.Appearance = loApprearance;
        
      page.AnnotationsWidget.Add(loStamp);

      string output = "ImageStamp.pdf";
      doc.SaveToFile(output);
  
    }
  }
}