Clipping pages in an existing 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.geom.Rectangle;
import com.itextpdf.kernel.pdf.PdfDocument;
import com.itextpdf.kernel.pdf.PdfPage;
import com.itextpdf.kernel.pdf.PdfReader;
import com.itextpdf.kernel.pdf.PdfWriter;
import com.itextpdf.kernel.pdf.canvas.PdfCanvas;

import java.io.File;
import java.util.Locale;

public class ClipPdf {
    public static final String DEST = "./target/sandbox/stamper/clip_pdf.pdf";
    public static final String SRC = "./src/main/resources/pdfs/hero.pdf";

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

        new ClipPdf().manipulatePdf(DEST);
    }

    protected void manipulatePdf(String dest) throws Exception {
        PdfDocument pdfDoc = new PdfDocument(new PdfReader(SRC), new PdfWriter(dest));

        for (int p = 1; p <= pdfDoc.getNumberOfPages(); p++) {
            PdfPage page = pdfDoc.getPage(p);
            Rectangle media = page.getCropBox();

            if (media == null) {
                media = page.getMediaBox();
            }
            float llx = media.getX() + 200;
            float lly = media.getY() + 200;
            float w = media.getWidth() - 400;
            float h = media.getHeight() - 400;

            // It's important to write explicit Locale settings, because decimal separator differs in
            // different regions and in PDF only dot is respected
            String command = String.format(Locale.ENGLISH,

                    // re operator constructs a rectangle
                    // W operator - sets the clipping path
                    // n operator - starts a new path
                    // q, Q - operators save and restore the graphics state stack
                    "\nq %.2f %.2f %.2f %.2f re W n\nq\n", llx, lly, w, h);

            // The content, placed on a content stream before, will be rendered before the other content
            // and, therefore, could be understood as a background (bottom "layer")
            PdfPage pdfPage = pdfDoc.getPage(p);
            new PdfCanvas(pdfPage.newContentStreamBefore(), pdfPage.getResources(), pdfDoc)
                    .writeLiteral(command);

            // The content, placed on a content stream after, will be rendered after the other content
            // and, therefore, could be understood as a foreground (top "layer")
            new PdfCanvas(pdfPage.newContentStreamAfter(), pdfPage.getResources(), pdfDoc)
                    .writeLiteral("\nQ\nQ\n");
        }

        pdfDoc.close();
    }
}

C#

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

namespace iText.Samples.Sandbox.Stamper 
{
    public class ClipPdf 
    {
        public static readonly String DEST = "results/sandbox/stamper/clip_pdf.pdf";
        public static readonly String SRC = "../../../resources/pdfs/hero.pdf";

        public static void Main(String[] args) 
        {
            FileInfo file = new FileInfo(DEST);
            file.Directory.Create();
            
            new ClipPdf().ManipulatePdf(DEST);
        }

        protected void ManipulatePdf(String dest) 
        {
            PdfDocument pdfDoc = new PdfDocument(new PdfReader(SRC), new PdfWriter(dest));
            
            for (int p = 1; p <= pdfDoc.GetNumberOfPages(); p++) 
            {
                PdfPage page = pdfDoc.GetPage(p);
                Rectangle media = page.GetCropBox();
                if (media == null) 
                {
                    media = page.GetMediaBox();
                }
                float llx = media.GetX() + 200;
                float lly = media.GetY() + 200;
                float w = media.GetWidth() - 400;
                float h = media.GetHeight() - 400;
                
                // It's important to write explicit Locale settings, because decimal separator differs in
                // different regions and in PDF only dot is respected
                String command = String.Format(System.Globalization.CultureInfo.InvariantCulture, 
                        
                                // re operator constructs a rectangle
                                // W operator - sets the clipping path
                                // n operator - starts a new path
                                // q, Q - operators save and restore the graphics state stack
                                "\nq {0:f} {1:f} {2:f} {3:f} re W n\nq\n", llx, lly, w, h);
                
                //q 200.00 200.00 195.00 442.00 re W n q
                
                // The content, placed on a content stream before, will be rendered before the other content
                // and, therefore, could be understood as a background (bottom "layer")
                PdfPage pdfPage = pdfDoc.GetPage(p);
                new PdfCanvas(pdfPage.NewContentStreamBefore(), pdfPage.GetResources(), pdfDoc)
                        .WriteLiteral(command);
                
                // The content, placed on a content stream after, will be rendered after the other content
                // and, therefore, could be understood as a foreground (top "layer")
                new PdfCanvas(pdfPage.NewContentStreamAfter(), pdfPage.GetResources(), pdfDoc)
                        .WriteLiteral("\nQ\nQ\n");
            }
            
            pdfDoc.Close();
        }
    }
}