Superimposing content from one PDF into another PDF

JAVA

/*
    This file is part of the iText (R) project.
    Copyright (c) 1998-2023 Apryse Group NV
    Authors: Apryse Software.

    For more information, please contact iText Software at this address:
    sales@itextpdf.com
 */
package com.itextpdf.samples.sandbox.stamper;

import com.itextpdf.kernel.pdf.PdfDocument;
import com.itextpdf.kernel.pdf.PdfReader;
import com.itextpdf.kernel.pdf.PdfWriter;
import com.itextpdf.kernel.pdf.canvas.PdfCanvas;
import com.itextpdf.kernel.pdf.xobject.PdfFormXObject;

import java.io.File;

public class SuperImpose {
    public static final String DEST = "./target/sandbox/stamper/super_impose.pdf";
    public static final String[] EXTRA = {
            "./src/main/resources/pdfs/hello.pdf",
            "./src/main/resources/pdfs/base_url.pdf",
            "./src/main/resources/pdfs/state.pdf"
    };
    public static final String SRC = "./src/main/resources/pdfs/primes.pdf";

    public static void main(String[] args) throws Exception {
        File file = new File(DEST);
        file.getParentFile().mkdirs();

        new SuperImpose().manipulatePdf(DEST);
    }

    protected void manipulatePdf(String dest) throws Exception {
        PdfDocument pdfDoc = new PdfDocument(new PdfReader(SRC), new PdfWriter(dest));
        PdfCanvas canvas = new PdfCanvas(pdfDoc.getFirstPage().newContentStreamBefore(),
                pdfDoc.getFirstPage().getResources(), pdfDoc);

        for (String path : EXTRA) {
            PdfDocument srcDoc = new PdfDocument(new PdfReader(path));
            PdfFormXObject page = srcDoc.getFirstPage().copyAsFormXObject(pdfDoc);
            canvas.addXObjectAt(page, 0, 0);
            srcDoc.close();
        }

        pdfDoc.close();
    }
}

C#

using System;
using System.IO;
using iText.Kernel.Pdf;
using iText.Kernel.Pdf.Canvas;
using iText.Kernel.Pdf.Xobject;

namespace iText.Samples.Sandbox.Stamper 
{
    public class SuperImpose 
    {
        public static readonly String DEST = "results/sandbox/stamper/super_impose.pdf";
        public static readonly String SRC = "../../../resources/pdfs/primes.pdf";
        public static readonly String[] EXTRA =
        {       "../../../resources/pdfs/hello.pdf", 
                "../../../resources/pdfs/base_url.pdf", 
                "../../../resources/pdfs/state.pdf"
                
        };
        
        public static void Main(String[] args) 
        {
            FileInfo file = new FileInfo(DEST);
            file.Directory.Create();
            
            new SuperImpose().ManipulatePdf(DEST);
        }

        protected void ManipulatePdf(String dest) 
        {
            PdfDocument pdfDoc = new PdfDocument(new PdfReader(SRC), new PdfWriter(dest));
            PdfCanvas canvas = new PdfCanvas(pdfDoc.GetFirstPage().NewContentStreamBefore(), 
                    pdfDoc.GetFirstPage().GetResources(), pdfDoc);
            
            foreach (String path in EXTRA) 
            {
                PdfDocument srcDoc = new PdfDocument(new PdfReader(path));
                PdfFormXObject page = srcDoc.GetFirstPage().CopyAsFormXObject(pdfDoc);
                canvas.AddXObjectAt(page, 0, 0);
                srcDoc.Close();
            }
            
            pdfDoc.Close();
        }
    }
}