[Java] [Apache PDFBox] Create a single page with three different pdf pages

If we want to create a pdf by putting 3 pages side by side, we can use the below approach.

Here we are trying to merge first 2 pages side by side and then, we are merging the third page with this newly created page.

This code is very useful if you are performing comparison between 2 pdf's and want to show the result of that comparison also.

import org.apache.pdfbox.cos.COSDictionary;
import org.apache.pdfbox.cos.COSName;
import org.apache.pdfbox.multipdf.LayerUtility;
import org.apache.pdfbox.multipdf.PDFMergerUtility;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.pdmodel.common.PDRectangle;
import org.apache.pdfbox.pdmodel.graphics.form.PDFormXObject;

import java.awt.geom.AffineTransform;
import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

public class pdfSideBySide {

    public static void mergeFileSideBySide(String file1Path, String file2path, String mergedfilepath,
                                           String mergedfilename, String layername1, String layername2) {
        File pdf1File = new File(file1Path);
        File pdf2File = new File(file2path);
        File outPdfFile = new File(mergedfilepath);
        PDDocument pdf1 = null;
        PDDocument pdf2 = null;
        PDDocument outPdf = null;
        try {
            pdf1 = PDDocument.load(pdf1File);
            pdf2 = PDDocument.load(pdf2File);
            outPdf = new PDDocument();

            // Create output PDF frame
            PDRectangle pdf1Frame = pdf1.getPage(0).getCropBox();
            PDRectangle pdf2Frame = pdf2.getPage(0).getCropBox();
            PDRectangle outPdfFrame = new PDRectangle(pdf1Frame.getWidth()+pdf2Frame.getWidth(), Math.max(pdf1Frame.getHeight(), pdf2Frame.getHeight()));

            // Create output page with calculated frame and add it to the document
            COSDictionary dict = new COSDictionary();
            dict.setItem(COSName.TYPE, COSName.PAGE);
            dict.setItem(COSName.MEDIA_BOX, outPdfFrame);
            dict.setItem(COSName.CROP_BOX, outPdfFrame);
            dict.setItem(COSName.ART_BOX, outPdfFrame);
            PDPage outPdfPage = new PDPage(dict);
            outPdf.addPage(outPdfPage);

            // Source PDF pages has to be imported as form XObjects to be able to insert them at a specific point in the output page
            LayerUtility layerUtility = new LayerUtility(outPdf);
            PDFormXObject formPdf1 = layerUtility.importPageAsForm(pdf1, 0);
            PDFormXObject formPdf2 = layerUtility.importPageAsForm(pdf2, 0);

            // Add form objects to output page
            AffineTransform afLeft = new AffineTransform();
            layerUtility.appendFormAsLayer(outPdfPage, formPdf1, afLeft, layername1);
            AffineTransform afRight = AffineTransform.getTranslateInstance(pdf1Frame.getWidth(), 0.0);
            layerUtility.appendFormAsLayer(outPdfPage, formPdf2, afRight, layername2);
            outPdf.save( outPdfFile + "//" + mergedfilename);

        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (pdf1 != null) pdf1.close();
                if (pdf2 != null) pdf2.close();
                if (outPdf != null) outPdf.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    public static void moveFile(String sourcefilepath, String targetfilepath) throws IOException {
        Path temp = Files.move
                (Paths.get(sourcefilepath),
                        Paths.get(targetfilepath));

        if(temp != null)
        {
            System.out.println("File renamed and moved successfully");
        }
        else
        {
            System.out.println("Failed to move the file");
        }
    }

    private static  void mergePDF(String filepath) throws IOException { ;
        File folder = new File(filepath);
        File[] listOfFiles = folder.listFiles();
        PDFMergerUtility pdfMerger = new PDFMergerUtility();
        pdfMerger.setDestinationFileName(filepath+ "Results.pdf");
        for(File file: listOfFiles) {
            pdfMerger.addSource(file);
        }
        pdfMerger.mergeDocuments(null);
        System.out.println("PDF Documents merged to a single file");
    }

    public static void main(String[] args) throws Exception {
        String file1path = "src//main//resources//RPT_CPSPM_18875164_7469.pdf";
        String file2path = "src//main//resources//sample-pdf-file.pdf";
        String layername1 = "left";
        String layername2 = "right";
        String mergedfilepath = "src//main//resources//";
        String mergedfilename = "abc.pdf";
        String totalMergedfilepath = mergedfilepath+mergedfilename;

        mergeFileSideBySide(file1path,file2path,mergedfilepath,mergedfilename,layername1,layername2);

        String finalReportPath = "src//main//resources//Report//";
        String finalreportname = "finalymegred.pdf";
        String layername3 = "top";
        String layername4 = "bottom";
       Thread.sleep(1000*2);
        mergeFileSideBySide(totalMergedfilepath, "sample-pdf-file.pdf",finalReportPath,
                finalreportname,layername3,layername4);

        mergePDF(finalReportPath);

    }
}